channels

build.gradle

@@ -57,7 +57,7 @@ plugins {
     id 'com.palantir.git-version'        version '0.13.0'       apply false
     id 'de.undercouch.download'          version '5.0.1'
     id 'com.github.gmazzo.buildconfig'   version '3.0.3'        apply false
-    id "com.diffplug.spotless"           version "6.7.2"
+    id 'com.diffplug.spotless'           version '6.7.2'        apply false
 }
 verifySettingsGradle()
 
@@ -90,7 +90,13 @@ idea {
         downloadSources = true
     }
 }
-apply from: Blowdryer.file('spotless.gradle')
+
+boolean disableSpotless = project.hasProperty("disableSpotless") ? project.disableSpotless.toBoolean() : false
+
+if (!disableSpotless) {
+    apply plugin: 'com.diffplug.spotless'
+    apply from: Blowdryer.file('spotless.gradle')
+}
 
 if(JavaVersion.current() != JavaVersion.VERSION_1_8) {
     throw new GradleException("This project requires Java 8, but it's running on " + JavaVersion.current())

dependencies.gradle

@@ -2,4 +2,5 @@
 
 dependencies {
     compile("com.github.GTNewHorizons:GTNHLib:0.0.1:dev")
+    runtime("com.github.GTNewHorizons:NotEnoughItems:2.2.20-GTNH:dev")
 }

docs/channels.md

@@ -0,0 +1,72 @@
+# Constructable Tool
+
+The convention is to use the stack size of tool stack to pass tier info.
+
+## Channels
+
+When one multi have multiple tiered component that can have interleaving tier, this becomes an obnoxious restriction, as
+one ItemStack cannot have two stack sizes at the same time.
+Here we use the item NBT to bypass this restriction.
+
+Basically, one hologram can contain multiple channels.
+Each channel can be identified with lower case strings and has the value being one positive Java int.
+There will be one and only one master channel and 0 or more sub channel.
+
+When a non-existent sub channel is queried, master channel will be used instead to fill its place.
+
+Structure element designers will usually not need to consider channels, i.e. proceed as if this concept does not exist, unless it must take input from multiple channels.
+
+Multi Designers will consider how to map each channel to each tiered component.
+He will be using `com.gtnewhorizon.structurelib.structure.StructureUtility.withChannel` to direct structure element on which channel to use.
+Conceptually, it will return an ItemStack with the master channel being the value of selected channel.
+In implementation, withChannel will return a new ItemStack with same item, nbt but different stack size.
+
+In any case, it is NOT safe to mutate or query this ItemStack beyond its stack size.
+What information this carries (beyond the stack size) is an implementation detail and should not be relied on.
+__For the future of mankind please do not rely on this.__
+
+### why is this called channel?
+
+IDK man, just give me a better name and I'd do the renaming.
+
+### Example: Multiblock Structure Designer
+
+GT++ Chemical Plant is a multi with 4 distinctly tiered component.
+
+It will use
+* master channel for its outer shell
+* channel `"casing"` for machine casings
+* channel `"pipe"` for pipe casings
+* channel `"coil"` for heating coils
+
+Its structure code will then look like
+```java
+.addElement('a', shellStructureElement())
+.addElement('b', withChannel("casing", machineCasingStructureElement()))
+.addElement('c', withChannel("pipe", pipeCasingStructureElement()))
+.addElement('d', withChannel("coil", coilStructureElement()))
+```
+
+whereas all these structure elements are designed without considering channels whatsoever
+
+### Example: Multi channel input Structure Element
+
+Suppose your hatch element has a required facing and can accept arbitrary meta tile entity, so it will need both meta id and facing input.
+
+
+It will use
+* master channel for its outer shell
+* channel `"casing"` for machine casings
+* channel `"pipe"` for pipe casings
+* channel `"coil"` for heating coils
+
+Its structure code will then look like
+```java
+.addElement('a', shellStructureElement())
+.addElement('b', withChannel("casing", machineCasingStructureElement()))
+.addElement('c', withChannel("pipe", pipeCasingStructureElement()))
+.addElement('d', withChannel("coil", coilStructureElement()))
+```
+
+whereas all these structure elements are designed without considering channels whatsoever
+

docs/walkthrough.md

@@ -0,0 +1,62 @@
+# StructureLib Developer Guide v0.1-SNAPSHOT
+
+## `IStructureDefinition`
+
+`IStructureDefinition` is the structure definition of your multi. You will have one `IStructureDefinition` for each multi.
+
+### Caching?
+
+You will construct this definition once per multi, either at class load or at first call to `getStructureDefinition()`.
+You can use a `ClassValue<IStructureDefinition<?>>` if you have a template for subclass.
+You can also use `StructureUtility.defer()` for simpler cases, but it is slightly less performant as it will allocate new
+objects on each structure check, whereas `ClassValue` will allocate once and cache it onwards.
+
+### Constructing
+
+IStructureDefinition is constructed using `IStructureDefinition#builder()`.
+
+Builder has two main methods
+1. `addShape` is a 2d string array describing the layout of structure. You can optionally use `StructureUtility#transpose()`
+to transpose the array to make the structure look nicer in source code.
+2. `addElement`. It takes a char identifier (mapped to a char in any of `addShape()` calls) and a IStructureElement.
+
+## `IStructureElement`
+
+`IStructureElement` are how you define which block will be accepted.
+They are simple stateless classes. They will rely on the multiblock controller to store any states they need.
+If you don't want to store these transient states in multiblock controller, you can use `StructureUtility#withContext()`
+
+They will usually come from `StructureUtility`.
+There is a vast library of `IStructureElement` there to cover basic needs.
+For more complex usage, you can define your own subclass, e.g. GregTech 5 Unofficial defines `ofHatchAdder()`, `ofCoil()`,
+`ofFrame()` and `buildHatchAdder()` in its `GT_StructureUtility` class.
+
+Here we will detail a few more complex `IStructureElement` that comes with standard library.
+
+### `ofBlocksTiered`
+
+This assumes you have a series of block, e.g. T1 motor, T2 motor, etc. Your multi will accept any of them (__as long as
+player does not mix them (*)__), but would like to know which is used.
+
+(*): Implementation wise, this structure element will only accept a block if its tier is the same as existing tier or
+if existing tier is unset (i.e. value of third argument)
+
+The first argument is tier extractor.
+You will need to provide a function to convert block+meta to a tier.
+This tier cam be an Enum, an Integer, a String, or basically anything.
+It doesn't even have to implement `Comparable`.
+The choice is yours.
+The extractor can return null and will never be passed a null block or an invalid block meta.
+
+The second argument is a list of all blocks you know that you will accept.
+This list is only for hint particle spawning and survival build.
+The hint/autoplace code will choose 1st pair to spawn/place if hologram has [channel data](./channels.md) of 1,
+2nd pair if 2, and so on.
+
+The third argument is the value when the tier has not been set by structure code.
+This means getter (5th argument) will usually return this upon first invocation for each round of structure check.
+
+The fourth argument will notify the multi of a tier change.
+
+The fifth argument is how multi notify the structure element about current tier.
+This is necessary as all structure element are stateless themselves.

src/main/java/com/gtnewhorizon/structurelib/ClientProxy.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
 import com.gtnewhorizon.structurelib.entity.fx.EntityFXBlockHint;
+import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
 import cpw.mods.fml.common.eventhandler.SubscribeEvent;
 import java.util.ArrayList;
@@ -14,6 +15,7 @@ import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiNewChat;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
 import net.minecraft.util.ChatComponentText;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
@@ -149,6 +151,11 @@ public class ClientProxy extends CommonProxy {
         return Minecraft.getMinecraft().theWorld.getTotalWorldTime();
     }
 
+    @Override
+    public void uploadChannels(ItemStack trigger) {
+        StructureLib.net.sendToServer(new SetChannelDataMessage(trigger));
+    }
+
     private static class HintParticleInfo {
         private final int x, y, z;
         private final List<EntityFXBlockHint> owner;

src/main/java/com/gtnewhorizon/structurelib/CommonProxy.java

@@ -5,6 +5,7 @@ import cpw.mods.fml.common.event.FMLPreInitializationEvent;
 import net.minecraft.block.Block;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
@@ -48,4 +49,6 @@ public class CommonProxy {
     public long getOverworldTime() {
         return MinecraftServer.getServer().getEntityWorld().getTotalWorldTime();
     }
+
+    public void uploadChannels(ItemStack trigger) {}
 }

src/main/java/com/gtnewhorizon/structurelib/GuiHandler.java

@@ -0,0 +1,23 @@
+package com.gtnewhorizon.structurelib;
+
+import com.gtnewhorizon.structurelib.gui.GuiScreenConfigureChannels;
+import cpw.mods.fml.common.network.IGuiHandler;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.world.World;
+
+public class GuiHandler implements IGuiHandler {
+    @Override
+    public Object getServerGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
+        return null;
+    }
+
+    @Override
+    public Object getClientGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
+        switch (ID) {
+            case 0:
+                return new GuiScreenConfigureChannels(player.inventory.getStackInSlot(x));
+            default:
+                return null;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/StructureLib.java

@@ -1,15 +1,18 @@
 package com.gtnewhorizon.structurelib;
 
 import com.gtnewhorizon.structurelib.block.BlockHint;
+import com.gtnewhorizon.structurelib.command.CommandConfigureChannels;
 import com.gtnewhorizon.structurelib.item.ItemBlockHint;
 import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
 import com.gtnewhorizon.structurelib.item.ItemFrontRotationTool;
 import com.gtnewhorizon.structurelib.net.AlignmentMessage;
+import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
 import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
 import com.gtnewhorizon.structurelib.util.XSTR;
 import cpw.mods.fml.common.Mod;
 import cpw.mods.fml.common.SidedProxy;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+import cpw.mods.fml.common.event.FMLServerStartingEvent;
 import cpw.mods.fml.common.network.NetworkRegistry;
 import cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper;
 import cpw.mods.fml.common.registry.GameRegistry;
@@ -49,10 +52,14 @@ public class StructureLib {
                 AlignmentMessage.ServerHandler.class, AlignmentMessage.AlignmentQuery.class, 0, Side.SERVER);
         net.registerMessage(AlignmentMessage.ClientHandler.class, AlignmentMessage.AlignmentData.class, 1, Side.CLIENT);
         net.registerMessage(UpdateHintParticleMessage.Handler.class, UpdateHintParticleMessage.class, 2, Side.CLIENT);
+        net.registerMessage(SetChannelDataMessage.Handler.class, SetChannelDataMessage.class, 3, Side.SERVER);
     }
 
     public static final XSTR RANDOM = new XSTR();
 
+    @Mod.Instance
+    static StructureLib INSTANCE;
+
     static Block blockHint;
     static Item itemBlockHint;
     static Item itemFrontRotationTool;
@@ -76,6 +83,12 @@ public class StructureLib {
                 itemConstructableTrigger = new ItemConstructableTrigger(),
                 itemConstructableTrigger.getUnlocalizedName());
         proxy.preInit(e);
+        NetworkRegistry.INSTANCE.registerGuiHandler(instance(), new GuiHandler());
+    }
+
+    @Mod.EventHandler
+    public void serverStarting(FMLServerStartingEvent e) {
+        e.registerServerCommand(new CommandConfigureChannels());
     }
 
     public static void addClientSideChatMessages(String... messages) {
@@ -93,4 +106,12 @@ public class StructureLib {
     public static long getOverworldTime() {
         return proxy.getOverworldTime();
     }
+
+    public static StructureLib instance() {
+        return INSTANCE;
+    }
+
+    public CommonProxy proxy() {
+        return proxy;
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/ChannelDataAccessor.java

@@ -0,0 +1,109 @@
+package com.gtnewhorizon.structurelib.alignment.constructable;
+
+import java.util.Locale;
+import java.util.Map.Entry;
+import java.util.stream.Stream;
+
+import com.gtnewhorizon.structurelib.StructureLib;
+import net.minecraft.init.Items;
+import net.minecraft.item.ItemStack;
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraftforge.common.util.Constants.NBT;
+import org.apache.commons.lang3.tuple.ImmutablePair;
+
+
+import static com.gtnewhorizon.structurelib.util.MiscUtils.getTagKeys;
+import static net.minecraftforge.common.util.Constants.NBT.TAG_COMPOUND;
+
+public class ChannelDataAccessor {
+    private static final String SECONDARY_HINT_TAG = "channels";
+
+    private ChannelDataAccessor() {}
+
+    public static ItemStack withChannel(ItemStack masterStack, String channel) {
+        if (channel == null || channel.isEmpty()) throw new IllegalArgumentException();
+        if (StructureLib.DEBUG_MODE && !channel.toLowerCase(Locale.ROOT).equals(channel))
+            throw new IllegalArgumentException("Channel name can be lower case ONLY");
+        if (!masterStack.hasTagCompound()
+                || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
+                || !masterStack
+                        .stackTagCompound
+                        .getCompoundTag(SECONDARY_HINT_TAG)
+                        .hasKey(channel, NBT.TAG_INT)) return masterStack;
+        ItemStack ret = new ItemStack(
+                masterStack.getItem(),
+                masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).getInteger(channel),
+                Items.feather.getDamage(masterStack));
+        ret.setTagCompound(masterStack.stackTagCompound);
+        return ret;
+    }
+
+    public static boolean hasSubChannel(ItemStack masterStack) {
+        return masterStack.hasTagCompound() && masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND);
+    }
+
+    public static boolean hasSubChannel(ItemStack masterStack, String channel) {
+        if (StructureLib.DEBUG_MODE && !channel.toLowerCase(Locale.ROOT).equals(channel))
+            throw new IllegalArgumentException("Channel name can be lower case ONLY");
+        return !channel.isEmpty()
+                && masterStack.hasTagCompound()
+                && masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
+                && masterStack
+                        .stackTagCompound
+                        .getCompoundTag(SECONDARY_HINT_TAG)
+                        .hasKey(channel, NBT.TAG_INT);
+    }
+
+    public static int getChannelData(ItemStack masterStack, String channel) {
+        if (channel == null || channel.isEmpty()) throw new IllegalArgumentException();
+        if (StructureLib.DEBUG_MODE && !channel.toLowerCase(Locale.ROOT).equals(channel))
+            throw new IllegalArgumentException("Channel name can be lower case ONLY");
+        if (!masterStack.hasTagCompound()
+                || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
+                || !masterStack
+                        .stackTagCompound
+                        .getCompoundTag(SECONDARY_HINT_TAG)
+                        .hasKey(channel, NBT.TAG_INT)) return masterStack.stackSize;
+        return masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).getInteger(channel);
+    }
+
+    public static void setChannelData(ItemStack masterStack, String channel, int data) {
+        if (channel == null || channel.isEmpty()) throw new IllegalArgumentException();
+        if (StructureLib.DEBUG_MODE && !channel.toLowerCase(Locale.ROOT).equals(channel))
+            throw new IllegalArgumentException("Channel name can be lower case ONLY");
+        if (data <= 0) throw new IllegalArgumentException();
+        if (masterStack.stackTagCompound == null) masterStack.stackTagCompound = new NBTTagCompound();
+        NBTTagCompound main = masterStack.stackTagCompound;
+        if (!main.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)) main.setTag(SECONDARY_HINT_TAG, new NBTTagCompound());
+        main.getCompoundTag(SECONDARY_HINT_TAG).setInteger(channel, data);
+    }
+
+    public static void unsetChannelData(ItemStack masterStack, String channel) {
+        if (channel == null || channel.isEmpty()) throw new IllegalArgumentException();
+        if (StructureLib.DEBUG_MODE && !channel.toLowerCase(Locale.ROOT).equals(channel))
+            throw new IllegalArgumentException("Channel name can be lower case ONLY");
+        if (masterStack.stackTagCompound == null) masterStack.stackTagCompound = new NBTTagCompound();
+        NBTTagCompound main = masterStack.stackTagCompound;
+        if (!main.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)) main.setTag(SECONDARY_HINT_TAG, new NBTTagCompound());
+        NBTTagCompound tag = main.getCompoundTag(SECONDARY_HINT_TAG);
+        tag.removeTag(channel);
+        if (tag.hasNoTags()) main.removeTag(SECONDARY_HINT_TAG);
+        if (main.hasNoTags()) masterStack.stackTagCompound = null;
+    }
+
+    public static void wipeChannelData(ItemStack masterStack) {
+        if (masterStack.stackTagCompound != null) masterStack.stackTagCompound.removeTag(SECONDARY_HINT_TAG);
+    }
+
+    public static Stream<Entry<String, Integer>> iterateChannelData(ItemStack masterStack) {
+        if (!hasSubChannel(masterStack)) return Stream.empty();
+        NBTTagCompound tag = masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG);
+        return getTagKeys(tag).stream().map(s -> new ImmutablePair<>(s, tag.getInteger(s)));
+    }
+
+    public static int countChannelData(ItemStack masterStack) {
+        if (!hasSubChannel(masterStack)) return 0;
+        NBTTagCompound tag = masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG);
+        return tag.func_150296_c().size();
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/command/CommandConfigureChannels.java

@@ -0,0 +1,121 @@
+package com.gtnewhorizon.structurelib.command;
+
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import net.minecraft.command.CommandBase;
+import net.minecraft.command.ICommandSender;
+import net.minecraft.command.WrongUsageException;
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.ChatComponentText;
+import net.minecraft.util.ChatComponentTranslation;
+
+public class CommandConfigureChannels extends CommandBase {
+    @Override
+    public String getCommandName() {
+        return "sl_channel";
+    }
+
+    @Override
+    public String getCommandUsage(ICommandSender p_71518_1_) {
+        return "/sl_channel <wipe/getall>\n" + "/sl_channel <get/unset> <channel name>\n"
+                + "/sl_channel <set> <channel name> <value>\n"
+                + "<channel name> can have space in it. <value> must be positive integer";
+    }
+
+    @Override
+    public int getRequiredPermissionLevel() {
+        return 0;
+    }
+
+    @Override
+    public List<?> addTabCompletionOptions(ICommandSender p_71516_1_, String[] p_71516_2_) {
+        if (p_71516_2_.length == 1)
+            return getListOfStringsMatchingLastWord(p_71516_2_, "get", "set", "unset", "wipe", "getall");
+        return null;
+    }
+
+    @Override
+    public void processCommand(ICommandSender sender, String[] args) {
+        if (args.length == 0) throw new WrongUsageException(getCommandUsage(sender));
+
+        if (!(sender instanceof EntityPlayerMP)) throw new WrongUsageException("must be a player");
+
+        EntityPlayerMP player = (EntityPlayerMP) sender;
+
+        ItemStack heldItem = player.getHeldItem();
+        if (heldItem == null || !(heldItem.getItem() instanceof ItemConstructableTrigger)) {
+            throw new WrongUsageException("must hold a hologram");
+        }
+
+        String channel;
+
+        switch (args[0]) {
+            case "getall":
+                if (!ChannelDataAccessor.hasSubChannel(heldItem)) {
+                    sender.addChatMessage(new ChatComponentText("No subchannel"));
+                } else {
+                    sender.addChatMessage(new ChatComponentTranslation(
+                            "item.structurelib.constructableTrigger.desc.lshift.0",
+                            ChannelDataAccessor.countChannelData(heldItem)));
+                    ChannelDataAccessor.iterateChannelData(heldItem)
+                            .map(e -> e.getKey() + ": " + e.getValue())
+                            .map(ChatComponentText::new)
+                            .forEach(player::addChatMessage);
+                }
+                return;
+            case "wipe":
+                ChannelDataAccessor.wipeChannelData(heldItem);
+                return;
+            case "get":
+            case "unset":
+                if (args.length < 2) throw new WrongUsageException(getCommandUsage(sender));
+                channel =
+                        args.length == 2 ? args[1] : Arrays.stream(args).skip(1).collect(Collectors.joining());
+                break;
+            case "set":
+                if (args.length < 3) throw new WrongUsageException(getCommandUsage(sender));
+                channel = args.length == 3
+                        ? args[1]
+                        : Arrays.stream(args).skip(1).limit(args.length - 2).collect(Collectors.joining());
+                break;
+            default:
+                throw new WrongUsageException(getCommandUsage(sender));
+        }
+
+        switch (args[0]) {
+            case "get":
+                if (ChannelDataAccessor.hasSubChannel(heldItem, channel))
+                    sender.addChatMessage(new ChatComponentText(
+                            channel + " value: " + ChannelDataAccessor.getChannelData(heldItem, channel)));
+                else sender.addChatMessage(new ChatComponentText(channel + " value: N/A"));
+                break;
+            case "clear":
+                if (ChannelDataAccessor.hasSubChannel(heldItem, channel))
+                    sender.addChatMessage(new ChatComponentText(channel + " no value"));
+                else {
+                    ChannelDataAccessor.unsetChannelData(heldItem, channel);
+                    sender.addChatMessage(new ChatComponentText(channel + " cleared"));
+                    player.inventoryContainer.detectAndSendChanges();
+                }
+                break;
+            case "set":
+                int value;
+                try {
+                    value = Integer.parseInt(args[args.length - 1]);
+                } catch (NumberFormatException e) {
+                    throw new WrongUsageException("%s not a valid value", args[args.length - 1]);
+                }
+
+                if (value <= 0) throw new WrongUsageException("%s not a valid value", args[args.length - 1]);
+
+                ChannelDataAccessor.setChannelData(heldItem, channel, value);
+                player.inventoryContainer.detectAndSendChanges();
+                sender.addChatMessage(new ChatComponentText(channel + " value: " + value));
+                break;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScreenConfigureChannels.java

@@ -0,0 +1,378 @@
+package com.gtnewhorizon.structurelib.gui;
+
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.gui.GuiScrollableList.IGuiScreen;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.gui.GuiTextField;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.resources.I18n;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.EnumChatFormatting;
+import net.minecraft.util.ResourceLocation;
+import org.apache.commons.lang3.StringUtils;
+import org.lwjgl.input.Keyboard;
+import org.lwjgl.input.Mouse;
+import org.lwjgl.opengl.GL11;
+
+public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen {
+    private static final int KEY_MAX_WIDTH = 50;
+    private final ItemStack trigger;
+    private final GuiChannelsList list;
+    private GuiTextField key, value;
+    protected int guiTop, guiLeft;
+
+    public GuiScreenConfigureChannels(ItemStack trigger) {
+        this.trigger = trigger;
+        list = new GuiChannelsList(152, 100, 12, 12, 14);
+        list.addSelectionListener((list, selectedIndex) -> {
+            Entry<String, Integer> e = list.getElementAt(selectedIndex);
+            key.setText(e.getKey());
+            value.setText(e.getValue().toString());
+            updateButtons();
+        });
+    }
+
+    @Override
+    public void initGui() {
+        super.initGui();
+        // so you can keep holding backspace to delete a long sequence of chars
+        Keyboard.enableRepeatEvents(true);
+
+        guiLeft = (this.width - this.getXSize()) / 2;
+        guiTop = (this.height - this.getYSize()) / 2;
+
+        key = new GuiTextField(fontRendererObj, guiLeft + 45, guiTop + 119, 151 + 12 - 45, 12) {
+            @Override
+            public void writeText(String text) {
+                // force lower case
+                super.writeText(text.toLowerCase(Locale.ROOT));
+                updateButtons();
+            }
+
+            @Override
+            public void mouseClicked(int p_146192_1_, int p_146192_2_, int p_146192_3_) {
+                super.mouseClicked(p_146192_1_, p_146192_2_, p_146192_3_);
+                boolean flag = p_146192_1_ >= this.xPosition
+                        && p_146192_1_ < this.xPosition + this.width
+                        && p_146192_2_ >= this.yPosition
+                        && p_146192_2_ < this.yPosition + this.height;
+                if (flag && p_146192_3_ == 1) {
+                    key.setText("");
+                    value.setText("");
+                }
+            }
+
+            @Override
+            public void setText(String p_146180_1_) {
+                super.setText(p_146180_1_);
+                updateButtons();
+            }
+        };
+        value = new GuiTextField(fontRendererObj, guiLeft + 45, guiTop + 139, 151 + 12 - 45, 12) {
+            @Override
+            public void writeText(String text) {
+                // ignore write requests containing non digit characters.
+                // we don't accept decimals or negative numbers, so we can safely use isDigit instead of something more
+                // advanced
+                // use codePoints() in case someone pasted an emoji by mistake
+                if (text != null && text.codePoints().allMatch(Character::isDigit)) {
+                    super.writeText(text);
+                    updateButtons();
+                }
+            }
+
+            @Override
+            public void setFocused(boolean p_146195_1_) {
+                if (!p_146195_1_ && isFocused()) {
+                    int result;
+                    try {
+                        result = Math.max(Integer.parseInt(getText()), 1);
+                    } catch (NumberFormatException e) {
+                        result = 1;
+                    }
+                    setText(String.valueOf(result));
+                }
+                super.setFocused(p_146195_1_);
+            }
+
+            @Override
+            public void mouseClicked(int p_146192_1_, int p_146192_2_, int p_146192_3_) {
+                super.mouseClicked(p_146192_1_, p_146192_2_, p_146192_3_);
+                boolean flag = p_146192_1_ >= this.xPosition
+                        && p_146192_1_ < this.xPosition + this.width
+                        && p_146192_2_ >= this.yPosition
+                        && p_146192_2_ < this.yPosition + this.height;
+                if (flag && p_146192_3_ == 1) {
+                    setText("");
+                }
+            }
+
+            @Override
+            public void setText(String p_146180_1_) {
+                super.setText(p_146180_1_);
+                updateButtons();
+            }
+        };
+
+        list.onGuiInit(this);
+
+        addButton(new GuiButton(
+                0, guiLeft + 12, guiTop + 157, 47, 20, I18n.format("item.structurelib.constructableTrigger.gui.add")));
+        addButton(new GuiButton(
+                1,
+                guiLeft + 65,
+                guiTop + 157,
+                47,
+                20,
+                I18n.format("item.structurelib.constructableTrigger.gui.unset")));
+        addButton(new GuiButton(
+                2,
+                guiLeft + 118,
+                guiTop + 157,
+                47,
+                20,
+                I18n.format("item.structurelib.constructableTrigger.gui.wipe")));
+
+        updateButtons();
+    }
+
+    @Override
+    public int getGuiLeft() {
+        return guiLeft;
+    }
+
+    @Override
+    public int getGuiTop() {
+        return guiTop;
+    }
+
+    @Override
+    public int getXSize() {
+        return 176;
+    }
+
+    @Override
+    public int getYSize() {
+        return 188;
+    }
+
+    @Override
+    public void addButton(GuiButton button) {
+        getButtonList().add(button);
+    }
+
+    @Override
+    public void removeButton(GuiButton button) {
+        getButtonList().remove(button);
+    }
+
+    @Override
+    public int getOverlayOffsetX() {
+        return 0;
+    }
+
+    @Override
+    public void doActionPerformed(GuiButton but) {
+        actionPerformed(but);
+    }
+
+    @SuppressWarnings("unchecked")
+    private List<GuiButton> getButtonList() {
+        return buttonList;
+    }
+
+    @Override
+    public void handleMouseInput() {
+        int delta = Mouse.getEventDWheel();
+        if (delta != 0) list.handleDWheel(delta);
+        super.handleMouseInput();
+    }
+
+    @Override
+    protected void mouseClicked(int mX, int mY, int button) {
+        key.mouseClicked(mX, mY, button);
+        value.mouseClicked(mX, mY, button);
+        super.mouseClicked(mX, mY, button);
+    }
+
+    @Override
+    protected void keyTyped(char aChar, int aKey) {
+        if (key.textboxKeyTyped(aChar, aKey)) {
+            updateButtons();
+            return;
+        }
+        if (value.textboxKeyTyped(aChar, aKey)) return;
+        super.keyTyped(aChar, aKey);
+    }
+
+    private void updateButtons() {
+        // this will be called from setText of key and value. NEVER UPDATE THE VALUE OF THESE HERE OR GET A
+        // STACKOVERFLOW!
+        boolean existing = ChannelDataAccessor.hasSubChannel(trigger, key.getText());
+        getButtonList().get(0).displayString = existing
+                ? I18n.format("item.structurelib.constructableTrigger.gui.set")
+                : I18n.format("item.structurelib.constructableTrigger.gui.add");
+        getButtonList().get(0).enabled = !StringUtils.isBlank(value.getText());
+        getButtonList().get(1).enabled = existing && !StringUtils.isBlank(value.getText());
+    }
+
+    private int getValue() {
+        try {
+            return Integer.parseInt(value.getText());
+        } catch (NumberFormatException e) {
+            return -1;
+        }
+    }
+
+    @Override
+    protected void actionPerformed(GuiButton btn) {
+        if (btn == null) return;
+        switch (btn.id) {
+            case 0:
+                int value = getValue();
+                if (value <= 0) return;
+                ChannelDataAccessor.setChannelData(trigger, key.getText(), value);
+                break;
+            case 1:
+                ChannelDataAccessor.unsetChannelData(trigger, key.getText());
+                break;
+            case 2:
+                ChannelDataAccessor.wipeChannelData(trigger);
+                break;
+        }
+        super.actionPerformed(btn);
+    }
+
+    @Override
+    public void onGuiClosed() {
+        super.onGuiClosed();
+        Keyboard.enableRepeatEvents(false);
+        StructureLib.instance().proxy().uploadChannels(trigger);
+    }
+
+    @Override
+    public void updateScreen() {
+        super.updateScreen();
+        key.updateCursorCounter();
+        value.updateCursorCounter();
+    }
+
+    @Override
+    public boolean doesGuiPauseGame() {
+        return false;
+    }
+
+    @Override
+    public void drawScreen(int mX, int mY, float partialTick) {
+        mc.renderEngine.bindTexture(new ResourceLocation("structurelib", "textures/gui/channels.png"));
+        int topLeftX = (this.width - this.getXSize()) / 2;
+        int topLeftY = (this.height - this.getYSize()) / 2;
+        drawTexturedModalRect(topLeftX, topLeftY, 0, 0, getXSize(), getYSize());
+        super.drawScreen(mX, mY, partialTick);
+        list.drawScreen(mX, mY, partialTick);
+        fontRendererObj.drawString(
+                I18n.format("item.structurelib.constructableTrigger.gui.key"), guiLeft + 12, guiTop + 122, 0);
+        key.drawTextBox();
+        fontRendererObj.drawString(
+                I18n.format("item.structurelib.constructableTrigger.gui.value"), guiLeft + 12, guiTop + 142, 0);
+        value.drawTextBox();
+    }
+
+    private class GuiChannelsList extends GuiScrollableList<Entry<String, Integer>> {
+        private List<Entry<String, Integer>> cache;
+
+        public GuiChannelsList(int width, int height, int originX, int originY, int slotHeight) {
+            super(width, height, originX, originY, slotHeight);
+        }
+
+        @Override
+        public Entry<String, Integer> getElementAt(int index) {
+            return ChannelDataAccessor.iterateChannelData(trigger)
+                    .sorted()
+                    .skip(index)
+                    .findFirst()
+                    .orElse(null);
+        }
+
+        @Override
+        public int getNumElements() {
+            return ChannelDataAccessor.countChannelData(trigger);
+        }
+
+        @Override
+        protected boolean elementClicked(int elementIndex, boolean doubleClick, int mXRelative, int mYRelative) {
+            if (mXRelative >= margin + 1
+                    && mXRelative <= margin + 5
+                    && mYRelative >= margin / 2 + 1
+                    && mYRelative <= margin / 2 + 5) {
+                Entry<String, Integer> e = getElementAt(elementIndex);
+                if (e != null) {
+                    ChannelDataAccessor.unsetChannelData(trigger, e.getKey());
+                    return false;
+                }
+            }
+            return super.elementClicked(elementIndex, doubleClick, mXRelative, mYRelative);
+        }
+
+        @Override
+        protected void prepareDrawElements() {
+            cache = ChannelDataAccessor.iterateChannelData(trigger).sorted().collect(Collectors.toList());
+        }
+
+        @Override
+        protected void drawElement(
+                int elementIndex, int x, int y, int height, Tessellator tessellator, boolean isHovering) {
+            if (elementIndex < 0 || elementIndex >= cache.size()) {
+                return;
+            }
+            Entry<String, Integer> e = cache.get(elementIndex);
+            if (e == null) return;
+            if (elementIndex > 0) {
+                // args x1, x2, y1, color
+                drawHorizontalLine(minX + 1, maxX - 1, y - 2, 0xffaaaaaa);
+            }
+            int keyMaxWidth = KEY_MAX_WIDTH * 2;
+            if (isHovering) {
+                mc.renderEngine.bindTexture(new ResourceLocation("structurelib", "textures/gui/channels.png"));
+                GL11.glColor4f(1, 1, 1, 1);
+                drawTexturedModalRect(x + margin + 1, y + margin / 2 + 1, 251, 251, 5, 5);
+            }
+            fontRendererObj.drawString(trim(e.getKey(), keyMaxWidth - 9), x + margin + 8, y + margin / 2, 0xffffff);
+            int valueX = x + margin + keyMaxWidth + margin;
+            fontRendererObj.drawString(trim(e.getValue().toString(), maxX - valueX), valueX, y + margin / 2, 0xffffff);
+        }
+
+        @Override
+        public void drawScreen(int mX, int mY, float partialTick) {
+            super.drawScreen(mX, mY, partialTick);
+            // args x1, y1, y2, color
+            drawVerticalLine(minX + margin + margin / 2 + KEY_MAX_WIDTH * 2, minY + 1, maxY - 1, 0xffaaaaaa);
+        }
+
+        public String trim(String e, int keyMaxWidth) {
+            // TODO optimize this to not create a billion string, or maybe cache this
+            String s = fontRendererObj.trimStringToWidth(e, keyMaxWidth);
+            if (s.length() != e.length()) {
+                StringBuilder buffer =
+                        new StringBuilder(s).deleteCharAt(s.length() - 1).append("...");
+                while ((s = fontRendererObj.trimStringToWidth(buffer.toString(), keyMaxWidth)).length()
+                        != buffer.length())
+                    // drop last original char
+                    buffer.deleteCharAt(s.length() - 4);
+                do {
+                    buffer.append('.');
+                } while (fontRendererObj.getStringWidth(buffer.toString()) <= keyMaxWidth);
+                s = buffer.deleteCharAt(s.length() - 1)
+                        .insert(s.length() - 3, EnumChatFormatting.GRAY)
+                        .toString();
+            }
+            return s;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScrollableList.java

@@ -0,0 +1,443 @@
+package com.gtnewhorizon.structurelib.gui;
+
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.ScaledResolution;
+import net.minecraft.client.renderer.Tessellator;
+import org.lwjgl.input.Mouse;
+import org.lwjgl.opengl.GL11;
+
+/**
+ * Shamelessly stolen from EnderCore, with some amount of edit to fit in one file. Original code from CrazyPants.
+ * <p>
+ * As the code has been released into public domain, it is now LGPL as part of this library as a whole.
+ * You can go to EnderCore's repository to obtain a public domain copy though
+ *
+ * Major edits
+ * <ul>
+ *     <li>Separate dwheel handling to handleDWheel. The next event calls often cause the mouse click event to
+ *     not fire on other widgets</li>
+ *     <li>scrollbar are now rendered within width</li>
+ *     <li>added prepareDrawElements</li>
+ * </ul>
+ *
+ * @author CrazyPants
+ * @author glee8e
+ */
+public abstract class GuiScrollableList<T> {
+    protected final int slotHeight;
+    private final Minecraft mc = Minecraft.getMinecraft();
+    protected int originX;
+    protected int originY;
+    protected int width;
+    protected int height;
+    protected int minY;
+    protected int maxY;
+    protected int minX;
+    protected int maxX;
+    protected int mouseX;
+    protected int mouseY;
+    protected int selectedIndex = -1;
+    protected int margin = 4;
+    protected List<ListSelectionListener<T>> listeners = new CopyOnWriteArrayList<>();
+    private int scrollUpButtonID;
+    private int scrollDownButtonID;
+    private float initialClickY = -2.0F;
+    private float scrollMultiplier;
+    private float amountScrolled;
+    private long lastClickedTime;
+
+    private boolean showSelectionBox = true;
+
+    public GuiScrollableList(int width, int height, int originX, int originY, int slotHeight) {
+        this.width = width;
+        this.height = height;
+        this.originX = originX;
+        this.originY = originY;
+        this.slotHeight = slotHeight;
+
+        minY = originY;
+        maxY = minY + height;
+        minX = originX;
+        maxX = minX + width;
+    }
+
+    public void onGuiInit(IGuiScreen gui) {
+        minY = originY + gui.getGuiTop();
+        maxY = minY + height;
+        minX = originX + gui.getGuiLeft();
+        maxX = minX + width;
+    }
+
+    public void addSelectionListener(ListSelectionListener<T> listener) {
+        listeners.add(listener);
+    }
+
+    public void removeSelectionListener(ListSelectionListener<T> listener) {
+        listeners.remove(listener);
+    }
+
+    public T getSelectedElement() {
+        return getElementAt(selectedIndex);
+    }
+
+    public void setSelection(T selection) {
+        setSelection(getIndexOf(selection));
+    }
+
+    public void setSelection(int index) {
+        if (index == selectedIndex) {
+            return;
+        }
+        selectedIndex = index;
+        for (ListSelectionListener<T> listener : listeners) {
+            listener.selectionChanged(this, selectedIndex);
+        }
+    }
+
+    public int getIndexOf(T element) {
+        if (element == null) {
+            return -1;
+        }
+        for (int i = 0; i < getNumElements(); i++) {
+            if (element.equals(getElementAt(i))) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    public abstract T getElementAt(int index);
+
+    public abstract int getNumElements();
+
+    protected abstract void drawElement(
+            int elementIndex, int x, int y, int height, Tessellator tessellator, boolean isHovering);
+
+    protected boolean elementClicked(int elementIndex, boolean doubleClick, int mXRelative, int mYRelative) {
+        return true;
+    }
+
+    public void setShowSelectionBox(boolean val) {
+        showSelectionBox = val;
+    }
+
+    protected int getContentHeight() {
+        return getNumElements() * slotHeight;
+    }
+
+    public void setScrollButtonIds(int scrollUpButtonID, int scrollDownButtonID) {
+        this.scrollUpButtonID = scrollUpButtonID;
+        this.scrollDownButtonID = scrollDownButtonID;
+    }
+
+    private void clampScrollToBounds() {
+        int i = getContentOverhang();
+        if (i < 0) {
+            i *= -1;
+        }
+        if (amountScrolled < 0.0F) {
+            amountScrolled = 0.0F;
+        }
+        if (amountScrolled > i) {
+            amountScrolled = i;
+        }
+    }
+
+    public int getContentOverhang() {
+        return getContentHeight() - (height - margin);
+    }
+
+    public void actionPerformed(GuiButton b) {
+        if (b.enabled) {
+            if (b.id == scrollUpButtonID) {
+                amountScrolled -= slotHeight * 2 / 3;
+                initialClickY = -2.0F;
+                clampScrollToBounds();
+            } else if (b.id == scrollDownButtonID) {
+                amountScrolled += slotHeight * 2 / 3;
+                initialClickY = -2.0F;
+                clampScrollToBounds();
+            }
+        }
+    }
+
+    /**
+     * draws the slot to the screen, pass in mouse's current x and y and partial
+     * ticks
+     */
+    public void drawScreen(int mX, int mY, float partialTick) {
+        this.mouseX = mX;
+        this.mouseY = mY;
+
+        processMouseEvents();
+
+        if (getContentOverhang() > 0) maxX = minX + width - 6;
+        else maxX = minX + width;
+
+        clampScrollToBounds();
+
+        GL11.glDisable(GL11.GL_LIGHTING);
+        GL11.glDisable(GL11.GL_FOG);
+
+        ScaledResolution sr = new ScaledResolution(mc, mc.displayWidth, mc.displayHeight);
+        int sx = minX * sr.getScaleFactor();
+        int sw = width * sr.getScaleFactor();
+        int sy = mc.displayHeight - (maxY * sr.getScaleFactor());
+        int sh = height * sr.getScaleFactor();
+        GL11.glEnable(GL11.GL_SCISSOR_TEST);
+        GL11.glScissor(sx, sy, sw, sh);
+
+        Tessellator tessellator = Tessellator.instance;
+        drawContainerBackground(tessellator);
+
+        int amountScrolled = (int) this.amountScrolled;
+        int contentYOffset = this.minY + margin - amountScrolled;
+
+        boolean hoveringPrecondition = mX >= minX && mX <= maxX && mY >= minY && mY <= maxY;
+
+        prepareDrawElements();
+
+        for (int i = 0; i < getNumElements(); ++i) {
+
+            int elementY = contentYOffset + i * this.slotHeight;
+            int slotHeight = this.slotHeight - margin;
+
+            if (elementY <= maxY && elementY + slotHeight >= minY) {
+
+                if (showSelectionBox && i == selectedIndex) {
+                    GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
+                    GL11.glDisable(GL11.GL_TEXTURE_2D);
+                    tessellator.startDrawingQuads();
+                    tessellator.setColorOpaque_I(8421504);
+                    tessellator.addVertexWithUV(minX, elementY + slotHeight + 2, 0.0D, 0.0D, 1.0D);
+                    tessellator.addVertexWithUV(maxX, elementY + slotHeight + 2, 0.0D, 1.0D, 1.0D);
+                    tessellator.addVertexWithUV(maxX, elementY - 2, 0.0D, 1.0D, 0.0D);
+                    tessellator.addVertexWithUV(minX, elementY - 2, 0.0D, 0.0D, 0.0D);
+                    tessellator.setColorOpaque_I(0);
+                    tessellator.addVertexWithUV(minX + 1, elementY + slotHeight + 1, 0.0D, 0.0D, 1.0D);
+                    tessellator.addVertexWithUV(maxX - 1, elementY + slotHeight + 1, 0.0D, 1.0D, 1.0D);
+                    tessellator.addVertexWithUV(maxX - 1, elementY - 1, 0.0D, 1.0D, 0.0D);
+                    tessellator.addVertexWithUV(minX + 1, elementY - 1, 0.0D, 0.0D, 0.0D);
+                    tessellator.draw();
+                    GL11.glEnable(GL11.GL_TEXTURE_2D);
+                }
+
+                boolean isHovering = hoveringPrecondition && elementY - 2 <= mY && mY < elementY + slotHeight + 2;
+                drawElement(i, minX, elementY, slotHeight, tessellator, isHovering);
+            }
+        }
+
+        GL11.glDisable(GL11.GL_SCISSOR_TEST);
+
+        GL11.glDisable(GL11.GL_DEPTH_TEST);
+        GL11.glEnable(GL11.GL_BLEND);
+        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
+        GL11.glDisable(GL11.GL_ALPHA_TEST);
+        GL11.glShadeModel(GL11.GL_SMOOTH);
+        GL11.glDisable(GL11.GL_TEXTURE_2D);
+
+        tessellator.startDrawingQuads();
+        tessellator.setColorRGBA_I(0, 0);
+        tessellator.addVertexWithUV(this.minX, this.minY + margin, 0.0D, 0.0D, 1.0D);
+        tessellator.addVertexWithUV(this.maxX, this.minY + margin, 0.0D, 1.0D, 1.0D);
+        tessellator.setColorRGBA_I(0, 255);
+        tessellator.addVertexWithUV(this.maxX, this.minY, 0.0D, 1.0D, 0.0D);
+        tessellator.addVertexWithUV(this.minX, this.minY, 0.0D, 0.0D, 0.0D);
+        tessellator.draw();
+        tessellator.startDrawingQuads();
+        tessellator.setColorRGBA_I(0, 255);
+        tessellator.addVertexWithUV(this.minX, this.maxY, 0.0D, 0.0D, 1.0D);
+        tessellator.addVertexWithUV(this.maxX, this.maxY, 0.0D, 1.0D, 1.0D);
+        tessellator.setColorRGBA_I(0, 0);
+        tessellator.addVertexWithUV(this.maxX, this.maxY - margin, 0.0D, 1.0D, 0.0D);
+        tessellator.addVertexWithUV(this.minX, this.maxY - margin, 0.0D, 0.0D, 0.0D);
+        tessellator.draw();
+
+        renderScrollBar(tessellator);
+
+        GL11.glEnable(GL11.GL_TEXTURE_2D);
+        GL11.glShadeModel(GL11.GL_FLAT);
+        GL11.glEnable(GL11.GL_ALPHA_TEST);
+        GL11.glDisable(GL11.GL_BLEND);
+    }
+
+    protected void prepareDrawElements() {}
+
+    protected void renderScrollBar(Tessellator tessellator) {
+
+        int contentHeightOverBounds = getContentOverhang();
+        if (contentHeightOverBounds > 0) {
+
+            int clear = (maxY - minY) * (maxY - minY) / getContentHeight();
+
+            if (clear < 32) {
+                clear = 32;
+            }
+
+            if (clear > maxY - minY - 8) {
+                clear = maxY - minY - 8;
+            }
+
+            int y = (int) this.amountScrolled * (maxY - minY - clear) / contentHeightOverBounds + minY;
+            if (y < minY) {
+                y = minY;
+            }
+
+            GL11.glDisable(GL11.GL_TEXTURE_2D);
+            int scrollBarMinX = getScrollBarX();
+            int scrollBarMaxX = scrollBarMinX + 6;
+            tessellator.startDrawingQuads();
+
+            tessellator.setColorRGBA_I(0, 255);
+            tessellator.addVertexWithUV(scrollBarMinX, maxY, 0.0D, 0.0D, 1.0D);
+            tessellator.addVertexWithUV(scrollBarMaxX, maxY, 0.0D, 1.0D, 1.0D);
+            tessellator.addVertexWithUV(scrollBarMaxX, minY, 0.0D, 1.0D, 0.0D);
+            tessellator.addVertexWithUV(scrollBarMinX, minY, 0.0D, 0.0D, 0.0D);
+
+            tessellator.setColorRGBA_F(0.3f, 0.3f, 0.3f, 1);
+            tessellator.addVertexWithUV(scrollBarMinX, (y + clear), 0.0D, 0.0D, 1.0D);
+            tessellator.addVertexWithUV(scrollBarMaxX, (y + clear), 0.0D, 1.0D, 1.0D);
+            tessellator.addVertexWithUV(scrollBarMaxX, y, 0.0D, 1.0D, 0.0D);
+            tessellator.addVertexWithUV(scrollBarMinX, y, 0.0D, 0.0D, 0.0D);
+
+            tessellator.setColorRGBA_F(0.7f, 0.7f, 0.7f, 1);
+            tessellator.addVertexWithUV(scrollBarMinX, (y + clear - 1), 0.0D, 0.0D, 1.0D);
+            tessellator.addVertexWithUV((scrollBarMaxX - 1), (y + clear - 1), 0.0D, 1.0D, 1.0D);
+            tessellator.addVertexWithUV((scrollBarMaxX - 1), y, 0.0D, 1.0D, 0.0D);
+            tessellator.addVertexWithUV(scrollBarMinX, y, 0.0D, 0.0D, 0.0D);
+
+            tessellator.draw();
+            GL11.glEnable(GL11.GL_TEXTURE_2D);
+        }
+    }
+
+    private void processMouseEvents() {
+        if (Mouse.isButtonDown(0)) {
+            processMouseBown();
+        } else {
+            initialClickY = -1.0F;
+        }
+    }
+
+    public void handleDWheel(int mouseWheelDelta) {
+        if (!Mouse.isButtonDown(0)) {
+            if (mouseWheelDelta > 0) {
+                amountScrolled -= slotHeight / 2;
+            } else /* if (mouseWheelDelta < 0) */ {
+                amountScrolled += slotHeight / 2;
+            }
+        }
+    }
+
+    private void processMouseBown() {
+        int contentHeightOverBounds;
+        if (initialClickY == -1.0F) {
+
+            if (mouseY >= minY && mouseY <= maxY && mouseX >= minX && mouseX <= maxX + 6) {
+
+                boolean clickInBounds = true;
+
+                int y = mouseY - minY + (int) amountScrolled - margin;
+                int mouseOverElement = y / slotHeight;
+
+                if (mouseX >= minX
+                        && mouseX <= maxX
+                        && mouseOverElement >= 0
+                        && y >= 0
+                        && mouseOverElement < getNumElements()) {
+                    boolean doubleClick =
+                            mouseOverElement == selectedIndex && Minecraft.getSystemTime() - lastClickedTime < 250L;
+                    if (elementClicked(
+                            mouseOverElement, doubleClick, mouseX - minX, y - slotHeight * mouseOverElement)) {
+                        setSelection(mouseOverElement);
+                        lastClickedTime = Minecraft.getSystemTime();
+                    }
+                } else if (mouseX >= minX && mouseX <= maxX && y < 0) {
+                    clickInBounds = false;
+                }
+
+                int scrollBarMinX = getScrollBarX();
+                int scrollBarMaxX = scrollBarMinX + 6;
+                if (mouseX >= scrollBarMinX && mouseX <= scrollBarMaxX) {
+
+                    scrollMultiplier = -1.0F;
+                    contentHeightOverBounds = getContentOverhang();
+
+                    if (contentHeightOverBounds < 1) {
+                        contentHeightOverBounds = 1;
+                    }
+
+                    int empty = (int) ((float) ((maxY - minY) * (maxY - minY)) / (float) getContentHeight());
+                    if (empty < 32) {
+                        empty = 32;
+                    }
+                    if (empty > maxY - minY - 8) {
+                        empty = maxY - minY - 8;
+                    }
+                    scrollMultiplier /= (float) (maxY - minY - empty) / (float) contentHeightOverBounds;
+
+                } else {
+                    scrollMultiplier = 1.0F;
+                }
+
+                if (clickInBounds) {
+                    initialClickY = mouseY;
+                } else {
+                    initialClickY = -2.0F;
+                }
+
+            } else {
+                initialClickY = -2.0F;
+            }
+
+        } else if (initialClickY >= 0.0F) {
+            // Scrolling
+            amountScrolled -= (mouseY - initialClickY) * scrollMultiplier;
+            initialClickY = mouseY;
+        }
+    }
+
+    protected int getScrollBarX() {
+        return maxX;
+    }
+
+    protected void drawContainerBackground(Tessellator tess) {
+        GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
+        GL11.glDisable(GL11.GL_TEXTURE_2D);
+        tess.startDrawingQuads();
+        tess.setColorOpaque_I(2105376);
+        tess.addVertex(minX, maxY, 0.0D);
+        tess.addVertex(maxX, maxY, 0.0D);
+        tess.addVertex(maxX, minY, 0.0D);
+        tess.addVertex(minX, minY, 0.0D);
+        tess.draw();
+        GL11.glEnable(GL11.GL_TEXTURE_2D);
+    }
+
+    public interface IGuiScreen {
+
+        int getGuiLeft();
+
+        int getGuiTop();
+
+        int getXSize();
+
+        int getYSize();
+
+        void addButton(GuiButton button);
+
+        void removeButton(GuiButton button);
+
+        int getOverlayOffsetX();
+
+        void doActionPerformed(GuiButton but);
+    }
+
+    public interface ListSelectionListener<T> {
+
+        void selectionChanged(GuiScrollableList<T> list, int selectedIndex);
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/item/ItemConstructableTrigger.java

@@ -3,8 +3,10 @@ package com.gtnewhorizon.structurelib.item;
 import static com.gtnewhorizon.structurelib.StructureLibAPI.MOD_ID;
 import static net.minecraft.util.EnumChatFormatting.BLUE;
 import static net.minecraft.util.StatCollector.translateToLocal;
+import static net.minecraft.util.StatCollector.translateToLocalFormatted;
 
 import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
 import com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility;
 import java.util.List;
 import net.minecraft.entity.Entity;
@@ -13,6 +15,7 @@ import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.world.World;
+import org.lwjgl.input.Keyboard;
 
 public class ItemConstructableTrigger extends Item {
     public ItemConstructableTrigger() {
@@ -21,6 +24,13 @@ public class ItemConstructableTrigger extends Item {
         setCreativeTab(StructureLib.creativeTab);
     }
 
+    @Override
+    public ItemStack onItemRightClick(ItemStack stack, World world, EntityPlayer player) {
+        if (world.isRemote && getMovingObjectPositionFromPlayer(world, player, true) == null)
+            player.openGui(StructureLib.instance(), 0, world, player.inventory.currentItem, 0, 0);
+        return super.onItemRightClick(stack, world, player);
+    }
+
     @Override
     public boolean onItemUseFirst(
             ItemStack stack,
@@ -39,19 +49,31 @@ public class ItemConstructableTrigger extends Item {
     @SuppressWarnings("unchecked")
     @Override
     public void addInformation(ItemStack aStack, EntityPlayer ep, List aList, boolean boo) {
-        aList.add(
-                translateToLocal("item.structurelib.constructableTrigger.desc.0")); // Triggers Constructable Interface
-        aList.add(BLUE
-                + translateToLocal(
-                        "item.structurelib.constructableTrigger.desc.1")); // Shows multiblock construction details,
-        aList.add(BLUE
-                + translateToLocal(
-                        "item.structurelib.constructableTrigger.desc.2")); // just Use on a multiblock controller.
-        aList.add(BLUE
-                + translateToLocal(
-                        "item.structurelib.constructableTrigger.desc.3")); // (Sneak Use in creative to build)
-        aList.add(BLUE
-                + translateToLocal("item.structurelib.constructableTrigger.desc.4")); // Quantity affects tier/mode/type
+        if (Keyboard.isKeyDown(Keyboard.KEY_LSHIFT)) {
+            aList.add(translateToLocalFormatted(
+                    "item.structurelib.constructableTrigger.desc.lshift.0",
+                    ChannelDataAccessor.countChannelData(aStack)));
+            ChannelDataAccessor.iterateChannelData(aStack)
+                    .map(e -> e.getKey() + ": " + e.getValue())
+                    .forEach(aList::add);
+        } else {
+            aList.add(translateToLocal(
+                    "item.structurelib.constructableTrigger.desc.0")); // Triggers Constructable Interface
+            aList.add(BLUE
+                    + translateToLocal(
+                            "item.structurelib.constructableTrigger.desc.1")); // Shows multiblock construction details,
+            aList.add(BLUE
+                    + translateToLocal(
+                            "item.structurelib.constructableTrigger.desc.2")); // just Use on a multiblock controller.
+            aList.add(BLUE
+                    + translateToLocal(
+                            "item.structurelib.constructableTrigger.desc.3")); // (Sneak Use in creative to build)
+            aList.add(BLUE
+                    + translateToLocal(
+                            "item.structurelib.constructableTrigger.desc.4")); // Quantity affects tier/mode/type
+            if (ChannelDataAccessor.hasSubChannel(aStack))
+                aList.add(translateToLocal("item.structurelib.constructableTrigger.desc.5"));
+        }
     }
 
     @Override

src/main/java/com/gtnewhorizon/structurelib/net/SetChannelDataMessage.java

@@ -0,0 +1,67 @@
+package com.gtnewhorizon.structurelib.net;
+
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
+import cpw.mods.fml.common.network.ByteBufUtils;
+import cpw.mods.fml.common.network.simpleimpl.IMessage;
+import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
+import cpw.mods.fml.common.network.simpleimpl.MessageContext;
+import io.netty.buffer.ByteBuf;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
+import org.apache.commons.lang3.tuple.Pair;
+
+public class SetChannelDataMessage implements IMessage {
+    private List<Map.Entry<String, Integer>> data = new ArrayList<>();
+
+    public SetChannelDataMessage() {}
+
+    public SetChannelDataMessage(ItemStack trigger) {
+        ChannelDataAccessor.iterateChannelData(trigger).forEach(data::add);
+    }
+
+    @Override
+    public void fromBytes(ByteBuf buf) {
+        data.clear();
+        int size = ByteBufUtils.readVarShort(buf);
+        for (int i = 0; i < size; i++) {
+            data.add(Pair.of(ByteBufUtils.readUTF8String(buf), ByteBufUtils.readVarInt(buf, 4)));
+        }
+    }
+
+    @Override
+    public void toBytes(ByteBuf buf) {
+        ByteBufUtils.writeVarShort(buf, data.size());
+        for (Entry<String, Integer> e : data) {
+            ByteBufUtils.writeUTF8String(buf, e.getKey());
+            ByteBufUtils.writeVarInt(buf, e.getValue(), 4);
+        }
+    }
+
+    public static class Handler implements IMessageHandler<SetChannelDataMessage, IMessage> {
+        @Override
+        public IMessage onMessage(SetChannelDataMessage message, MessageContext ctx) {
+            EntityPlayerMP player = ctx.getServerHandler().playerEntity;
+            ItemStack heldItem = player.getHeldItem();
+            if (heldItem != null && heldItem.getItem() instanceof ItemConstructableTrigger) {
+                ChannelDataAccessor.wipeChannelData(heldItem);
+                for (Entry<String, Integer> e : message.data) {
+                    ChannelDataAccessor.setChannelData(heldItem, e.getKey(), e.getValue());
+                }
+                // since this is a set all channel request from the client, we would assume client already know
+                // what this would look like on the client, so no sync
+            } else {
+                StructureLib.LOGGER.warn(
+                        "{} trying to set channel data on {}, which is not a hologram projector!",
+                        player.getUniqueID(),
+                        heldItem);
+            }
+            return null;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/structure/StructureUtility.java

@@ -5,6 +5,7 @@ import static java.lang.Integer.MIN_VALUE;
 
 import com.gtnewhorizon.structurelib.StructureLib;
 import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
 import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
 import com.gtnewhorizon.structurelib.structure.IStructureElement.PlaceResult;
 import com.gtnewhorizon.structurelib.structure.adders.IBlockAdder;
@@ -1895,6 +1896,42 @@ public class StructureUtility {
 
     // endregion
 
+    // region channels
+
+    /**
+     * See channels.md in docs folder
+     */
+    public static <T> IStructureElement<T> withChannel(String channel, IStructureElement<T> backing) {
+        return new IStructureElement<T>() {
+            public boolean check(T t, World world, int x, int y, int z) {
+                return backing.check(t, world, x, y, z);
+            }
+
+            public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return backing.spawnHint(t, world, x, y, z, ChannelDataAccessor.withChannel(trigger, channel));
+            }
+
+            public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return backing.placeBlock(t, world, x, y, z, ChannelDataAccessor.withChannel(trigger, channel));
+            }
+
+            public PlaceResult survivalPlaceBlock(
+                    T t,
+                    World world,
+                    int x,
+                    int y,
+                    int z,
+                    ItemStack trigger,
+                    IItemSource s,
+                    EntityPlayerMP actor,
+                    Consumer<IChatComponent> chatter) {
+                return backing.survivalPlaceBlock(
+                        t, world, x, y, z, ChannelDataAccessor.withChannel(trigger, channel), s, actor, chatter);
+            }
+        };
+    }
+    // endregion
+
     /**
      * Used internally, to generate skips for structure definitions
      */

src/main/resources/assets/structurelib/lang/en_US.lang

@@ -26,7 +26,15 @@ item.structurelib.constructableTrigger.desc.1=Shows multiblock construction sche
 item.structurelib.constructableTrigger.desc.2=use on the multiblock controller.
 item.structurelib.constructableTrigger.desc.3=(Sneak use on controller to build)
 item.structurelib.constructableTrigger.desc.4=Quantity of schematics in item stack affects tier/mode/type
+item.structurelib.constructableTrigger.desc.5=Hold §l[LSHIFT]§r to display channel data
+item.structurelib.constructableTrigger.desc.lshift.0=Contain %d sub channel.
 item.structurelib.constructableTrigger.too_fast=Please wait %d ticks before another autoplace...
+item.structurelib.constructableTrigger.gui.key=Key:
+item.structurelib.constructableTrigger.gui.value=Value:
+item.structurelib.constructableTrigger.gui.add=Add
+item.structurelib.constructableTrigger.gui.set=Set
+item.structurelib.constructableTrigger.gui.unset=Unset
+item.structurelib.constructableTrigger.gui.wipe=§4Wipe
 
 structurelib.autoplace.built_stat=Built %s blocks
 structurelib.autoplace.complete=§aThis multiblock has completed!

src/main/resources/assets/structurelib/lang/zh_CN.lang

@@ -26,8 +26,17 @@ item.structurelib.constructableTrigger.desc.1=只能在多方块主机上使用
 item.structurelib.constructableTrigger.desc.2=结构的示意图。 (译者注：请搭高使用)
 item.structurelib.constructableTrigger.desc.3= (潜行右键可以直接完成搭建)
 item.structurelib.constructableTrigger.desc.4=此物品堆叠数量会影响显示的机器等级/模式/类型
+item.structurelib.constructableTrigger.desc.5=按下 §l[左SHIFT]§r 以显示子信道
+item.structurelib.constructableTrigger.desc.lshift.0=包含 %d 个子信道
 item.structurelib.constructableTrigger.too_fast=请在下一次自动搭建前等待%dtick...
+item.structurelib.constructableTrigger.gui.key=信道名:
+item.structurelib.constructableTrigger.gui.value=值:
+item.structurelib.constructableTrigger.gui.add=添加
+item.structurelib.constructableTrigger.gui.set=替换
+item.structurelib.constructableTrigger.gui.unset=删除
+item.structurelib.constructableTrigger.gui.wipe=§4全部清空
 
+structurelib.autoplace.built_stat=已放置 %s 个方块
 structurelib.autoplace.complete=§a这个多方块结构已经完成自动搭建！
 structurelib.autoplace.error.not_enabled=§c这个多方块结构不支持在生存模式下自动搭建！
 structurelib.autoplace.error.no_simple_block=§c建议放置§r%s§c，但没有找到它