ItemSerialization.java

package de.kumpelblase2.remoteentities.utilities;

import java.io.*;
import java.lang.reflect.Method;
import net.minecraft.server.v1_7_R1.*;
import org.bukkit.craftbukkit.v1_7_R1.inventory.CraftInventoryCustom;
import org.bukkit.craftbukkit.v1_7_R1.inventory.CraftItemStack;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder;

/**
 * Made by Comprehenix.
 * Code can be found at: https://gist.github.com/aadnk/8138345
 */
public class ItemSerialization {

	private static Method WRITE_NBT;
	private static Method READ_NBT;

	/**
	 * Serializes an inventory to a encoded string.
	 *
	 * @param inventory The inventory to serialize
	 * @return          serialized string
	 */
	public static String toString(Inventory inventory) {
		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		DataOutputStream dataOutput = new DataOutputStream(outputStream);
		NBTTagList itemList = new NBTTagList();

		// Save every element in the list
		for (int i = 0; i < inventory.getSize(); i++) {
			NBTTagCompound outputObject = new NBTTagCompound();
			CraftItemStack craft = getCraftVersion(inventory.getItem(i));

			// Convert the item stack to a NBT compound
			if (craft != null)
				CraftItemStack.asNMSCopy(craft).save(outputObject);
			itemList.add(outputObject);
		}

		// Now save the list
		writeNbt(itemList, dataOutput);

		// Serialize that array
		return Base64Coder.encodeLines(outputStream.toByteArray());
	}

	/**
	 * Deserializes an inventory from a string
	 *
	 * @param data  String to deserialize
	 * @return      Deserialized inventory
	 */
	public static Inventory fromString(String data) {
		ByteArrayInputStream inputStream = new ByteArrayInputStream(Base64Coder.decodeLines(data));
		NBTTagList itemList = (NBTTagList) readNbt(new DataInputStream(inputStream), 0);
		Inventory inventory = new CraftInventoryCustom(null, itemList.size());

		for (int i = 0; i < itemList.size(); i++) {
			NBTTagCompound inputObject = itemList.get(i);

			if (!inputObject.isEmpty()) {
				inventory.setItem(i, CraftItemStack.asCraftMirror(
						net.minecraft.server.v1_7_R1.ItemStack.createStack(inputObject)));
			}
		}

		// Serialize that array
		return inventory;
	}

	private static void writeNbt(NBTBase base, DataOutput output) {
		if (WRITE_NBT == null) {
			try {
				WRITE_NBT = NBTCompressedStreamTools.class.getDeclaredMethod("a", NBTBase.class, DataOutput.class);
				WRITE_NBT.setAccessible(true);
			} catch (Exception e) {
				throw new IllegalStateException("Unable to find private write method.", e);
			}
		}

		try {
			WRITE_NBT.invoke(null, base, output);
		} catch (Exception e) {
			throw new IllegalArgumentException("Unable to write " + base + " to " + output, e);
		}
	}

	private static NBTBase readNbt(DataInput input, int level) {
		if (READ_NBT == null) {
			try {
				READ_NBT = NBTCompressedStreamTools.class.getDeclaredMethod("a", DataInput.class, int.class);
				READ_NBT.setAccessible(true);
			} catch (Exception e) {
				throw new IllegalStateException("Unable to find private read method.", e);
			}
		}

		try {
			return (NBTBase) READ_NBT.invoke(null, input, level);
		} catch (Exception e) {
			throw new IllegalArgumentException("Unable to read from " + input, e);
		}
	}

	private static CraftItemStack getCraftVersion(ItemStack stack) {
		if (stack instanceof CraftItemStack)
			return (CraftItemStack) stack;
		else if (stack != null)
			return CraftItemStack.asCraftCopy(stack);
		else
			return null;
	}
}