Java tutorial
/** * Copyright 2013 - 2013 Scott Woodward * * This file is part of RPItems * * RPItems is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * RPItems is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with RPItems. If not, see <http://www.gnu.org/licenses/>. */ package com.scottwoodward.rpitems.items; import java.io.BufferedInputStream; import java.io.DataInput; import java.io.DataInputStream; import java.io.DataOutput; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.util.AbstractList; import java.util.AbstractMap; import java.util.AbstractSet; import java.util.Arrays; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentMap; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; import org.bukkit.Bukkit; import org.bukkit.Material; import org.bukkit.Server; import org.bukkit.inventory.ItemStack; import com.google.common.base.Splitter; import com.google.common.collect.BiMap; import com.google.common.collect.HashBiMap; import com.google.common.collect.Lists; import com.google.common.collect.MapMaker; import com.google.common.io.Closeables; import com.google.common.io.Files; import com.google.common.io.InputSupplier; import com.google.common.io.OutputSupplier; import com.google.common.primitives.Primitives; public class NbtFactory { // Convert between NBT id and the equivalent class in java private static final BiMap<Integer, Class<?>> NBT_CLASS = HashBiMap.create(); private static final BiMap<Integer, NbtType> NBT_ENUM = HashBiMap.create(); /** * Whether or not to enable stream compression. * @author Kristian */ public enum StreamOptions { NO_COMPRESSION, GZIP_COMPRESSION, } private enum NbtType { TAG_END(0, Void.class), TAG_BYTE(1, byte.class), TAG_SHORT(2, short.class), TAG_INT(3, int.class), TAG_LONG( 4, long.class), TAG_FLOAT(5, float.class), TAG_DOUBLE(6, double.class), TAG_BYTE_ARRAY(7, byte[].class), TAG_INT_ARRAY(11, int[].class), TAG_STRING(8, String.class), TAG_LIST(9, List.class), TAG_COMPOUND(10, Map.class); // Unique NBT id public final int id; private NbtType(int id, Class<?> type) { this.id = id; NBT_CLASS.put(id, type); NBT_ENUM.put(id, this); } private String getFieldName() { if (this == TAG_COMPOUND) return "map"; else if (this == TAG_LIST) return "list"; else return "data"; } } // The NBT base class private Class<?> BASE_CLASS; private Class<?> COMPOUND_CLASS; private Class<?> STREAM_TOOLS; private Method NBT_CREATE_TAG; private Method NBT_GET_TYPE; private Field NBT_LIST_TYPE; private final Field[] DATA_FIELD = new Field[12]; // CraftItemStack private Class<?> CRAFT_STACK; private Field CRAFT_HANDLE; private Field STACK_TAG; // Loading/saving compounds private Method LOAD_COMPOUND; private Method SAVE_COMPOUND; // Shared instance private static NbtFactory INSTANCE; /** * Represents a root NBT compound. * <p> * All changes to this map will be reflected in the underlying NBT compound. Values may only be one of the following: * <ul> * <li>Primitive types</li> * <li>{@link java.lang.String String}</li> * <li>{@link NbtList}</li> * <li>{@link NbtCompound}</li> * </ul> * <p> * See also: * <ul> * <li>{@link NbtFactory#createCompound()}</li> * <li>{@link NbtFactory#fromCompound(Object)}</li> * </ul> * @author Kristian */ public final class NbtCompound extends ConvertedMap { private NbtCompound(Object handle) { super(handle, getDataMap(handle)); } // Simplifiying access to each value public Byte getByte(String key, Byte defaultValue) { return containsKey(key) ? (Byte) get(key) : defaultValue; } public Short getShort(String key, Short defaultValue) { return containsKey(key) ? (Short) get(key) : defaultValue; } public Integer getInteger(String key, Integer defaultValue) { return containsKey(key) ? (Integer) get(key) : defaultValue; } public Long getLong(String key, Long defaultValue) { return containsKey(key) ? (Long) get(key) : defaultValue; } public Float getFloat(String key, Float defaultValue) { return containsKey(key) ? (Float) get(key) : defaultValue; } public Double getDouble(String key, Double defaultValue) { return containsKey(key) ? (Double) get(key) : defaultValue; } public String getString(String key, String defaultValue) { return containsKey(key) ? (String) get(key) : defaultValue; } public byte[] getByteArray(String key, byte[] defaultValue) { return containsKey(key) ? (byte[]) get(key) : defaultValue; } public int[] getIntegerArray(String key, int[] defaultValue) { return containsKey(key) ? (int[]) get(key) : defaultValue; } /** * Retrieve the list by the given name. * @param key - the name of the list. * @param createNew - whether or not to create a new list if its missing. * @return An existing list, a new list or NULL. */ public NbtList getList(String key, boolean createNew) { NbtList list = (NbtList) get(key); if (list == null) put(key, list = createList()); return list; } /** * Retrieve the map by the given name. * @param key - the name of the map. * @param createNew - whether or not to create a new map if its missing. * @return An existing map, a new map or NULL. */ public NbtCompound getMap(String key, boolean createNew) { return getMap(Arrays.asList(key), createNew); } // Done /** * Set the value of an entry at a given location. * <p> * Every element of the path (except the end) are assumed to be compounds, and will * be created if they are missing. * @param path - the path to the entry. * @param value - the new value of this entry. * @return This compound, for chaining. */ public NbtCompound putPath(String path, Object value) { List<String> entries = getPathElements(path); Map<String, Object> map = getMap(entries.subList(0, entries.size() - 1), true); map.put(entries.get(entries.size() - 1), value); return this; } /** * Retrieve the value of a given entry in the tree. * <p> * Every element of the path (except the end) are assumed to be compounds. The * retrieval operation will be cancelled if any of them are missing. * @param path - path to the entry. * @return The value, or NULL if not found. */ @SuppressWarnings("unchecked") public <T> T getPath(String path) { List<String> entries = getPathElements(path); NbtCompound map = getMap(entries.subList(0, entries.size() - 1), false); if (map != null) { return (T) map.get(entries.get(entries.size() - 1)); } return null; } /** * Save the content of a NBT compound to a stream. * <p> * Use {@link Files#newOutputStreamSupplier(java.io.File)} to provide a stream supplier to a file. * @param stream - the output stream. * @param option - whether or not to compress the output. * @throws IOException If anything went wrong. */ public void saveTo(OutputSupplier<? extends OutputStream> stream, StreamOptions option) throws IOException { saveStream(this, stream, option); } /** * Retrieve a map from a given path. * @param path - path of compounds to look up. * @param createNew - whether or not to create new compounds on the way. * @return The map at this location. */ private NbtCompound getMap(Iterable<String> path, boolean createNew) { NbtCompound current = this; for (String entry : path) { NbtCompound child = (NbtCompound) current.get(entry); if (child == null) { if (!createNew) return null; current.put(entry, child = createCompound()); } current = child; } return current; } /** * Split the path into separate elements. * @param path - the path to split. * @return The elements. */ private List<String> getPathElements(String path) { return Lists.newArrayList(Splitter.on(".").omitEmptyStrings().split(path)); } } /** * Represents a root NBT list. * See also: * <ul> * <li>{@link NbtFactory#createNbtList()}</li> * <li>{@link NbtFactory#fromList(Object)}</li> * </ul> * @author Kristian */ public final class NbtList extends ConvertedList { private NbtList(Object handle) { super(handle, getDataList(handle)); } } /** * Represents an object that provides a view of a native NMS class. * @author Kristian */ public static interface Wrapper { /** * Retrieve the underlying native NBT tag. * @return The underlying NBT. */ public Object getHandle(); } /** * Retrieve or construct a shared NBT factory. * @return The factory. */ private static NbtFactory get() { if (INSTANCE == null) INSTANCE = new NbtFactory(); return INSTANCE; } /** * Construct an instance of the NBT factory by deducing the class of NBTBase. */ private NbtFactory() { if (BASE_CLASS == null) { try { // Keep in mind that I do use hard-coded field names - but it's okay as long as we're dealing // with CraftBukkit or its derivatives. This does not work in MCPC+ however. ClassLoader loader = NbtFactory.class.getClassLoader(); String packageName = getPackageName(); Class<?> offlinePlayer = loader.loadClass(packageName + ".CraftOfflinePlayer"); // Prepare NBT COMPOUND_CLASS = getMethod(0, Modifier.STATIC, offlinePlayer, "getData").getReturnType(); BASE_CLASS = COMPOUND_CLASS.getSuperclass(); NBT_GET_TYPE = getMethod(0, Modifier.STATIC, BASE_CLASS, "getTypeId"); NBT_CREATE_TAG = getMethod(Modifier.STATIC, 0, BASE_CLASS, "createTag", byte.class); // Prepare CraftItemStack CRAFT_STACK = loader.loadClass(packageName + ".inventory.CraftItemStack"); CRAFT_HANDLE = getField(null, CRAFT_STACK, "handle"); STACK_TAG = getField(null, CRAFT_HANDLE.getType(), "tag"); // Loading/saving STREAM_TOOLS = loader.loadClass(BASE_CLASS.getPackage().getName() + ".NBTCompressedStreamTools"); LOAD_COMPOUND = getMethod(Modifier.STATIC, 0, STREAM_TOOLS, null, DataInput.class); SAVE_COMPOUND = getMethod(Modifier.STATIC, 0, STREAM_TOOLS, null, BASE_CLASS, DataOutput.class); } catch (ClassNotFoundException e) { throw new IllegalStateException("Unable to find offline player.", e); } } } private String getPackageName() { Server server = Bukkit.getServer(); String name = server != null ? server.getClass().getPackage().getName() : null; if (name != null && name.contains("craftbukkit")) { return name; } else { // Fallback return "org.bukkit.craftbukkit.v1_7_R1"; } } @SuppressWarnings("unchecked") private Map<String, Object> getDataMap(Object handle) { return (Map<String, Object>) getFieldValue(getDataField(NbtType.TAG_COMPOUND, handle), handle); } @SuppressWarnings("unchecked") private List<Object> getDataList(Object handle) { return (List<Object>) getFieldValue(getDataField(NbtType.TAG_LIST, handle), handle); } /** * Construct a new NBT list of an unspecified type. * @return The NBT list. */ public static NbtList createList(Object... content) { return createList(Arrays.asList(content)); } /** * Construct a new NBT list of an unspecified type. * @return The NBT list. */ public static NbtList createList(Iterable<? extends Object> iterable) { NbtList list = get().new NbtList(INSTANCE.createNbtTag(NbtType.TAG_LIST, null)); // Add the content as well for (Object obj : iterable) list.add(obj); return list; } /** * Construct a new NBT compound. * <p> * Use {@link NbtCompound#asMap()} to modify it. * @return The NBT compound. */ public static NbtCompound createCompound() { return get().new NbtCompound(INSTANCE.createNbtTag(NbtType.TAG_COMPOUND, null)); } /** * Construct a new NBT wrapper from a list. * @param nmsList - the NBT list. * @return The wrapper. */ public static NbtList fromList(Object nmsList) { return get().new NbtList(nmsList); } /** * Load the content of a file from a stream. * <p> * Use {@link Files#newInputStreamSupplier(java.io.File)} to provide a stream from a file. * @param stream - the stream supplier. * @param option - whether or not to decompress the input stream. * @return The decoded NBT compound. * @throws IOException If anything went wrong. */ public static NbtCompound fromStream(InputSupplier<? extends InputStream> stream, StreamOptions option) throws IOException { InputStream input = null; DataInputStream data = null; try { input = stream.getInput(); data = new DataInputStream(new BufferedInputStream( option == StreamOptions.GZIP_COMPRESSION ? new GZIPInputStream(input) : input)); return fromCompound(invokeMethod(get().LOAD_COMPOUND, null, data)); } finally { if (data != null) Closeables.closeQuietly(data); if (input != null) Closeables.closeQuietly(input); } } /** * Save the content of a NBT compound to a stream. * <p> * Use {@link Files#newOutputStreamSupplier(java.io.File)} to provide a stream supplier to a file. * @param source - the NBT compound to save. * @param stream - the stream. * @param option - whether or not to compress the output. * @throws IOException If anything went wrong. */ public static void saveStream(NbtCompound source, OutputSupplier<? extends OutputStream> stream, StreamOptions option) throws IOException { OutputStream output = null; DataOutputStream data = null; try { output = stream.getOutput(); data = new DataOutputStream( option == StreamOptions.GZIP_COMPRESSION ? new GZIPOutputStream(output) : output); invokeMethod(get().SAVE_COMPOUND, null, source.getHandle(), data); } finally { if (data != null) Closeables.closeQuietly(data); if (output != null) Closeables.closeQuietly(output); } } /** * Construct a new NBT wrapper from a compound. * @param nmsCompound - the NBT compund. * @return The wrapper. */ public static NbtCompound fromCompound(Object nmsCompound) { return get().new NbtCompound(nmsCompound); } /** * Set the NBT compound tag of a given item stack. * <p> * The item stack must be a wrapper for a CraftItemStack. Use * {@link MinecraftReflection#getBukkitItemStack(ItemStack)} if not. * @param stack - the item stack, cannot be air. * @param compound - the new NBT compound, or NULL to remove it. * @throws IllegalArgumentException If the stack is not a CraftItemStack, or it represents air. */ public static void setItemTag(ItemStack stack, NbtCompound compound) { checkItemStack(stack); Object nms = getFieldValue(get().CRAFT_HANDLE, stack); // Now update the tag compound setFieldValue(get().STACK_TAG, nms, compound.getHandle()); } /** * Construct a wrapper for an NBT tag stored (in memory) in an item stack. This is where * auxillary data such as enchanting, name and lore is stored. It does not include items * material, damage value or count. * <p> * The item stack must be a wrapper for a CraftItemStack. * @param stack - the item stack. * @return A wrapper for its NBT tag. */ public static NbtCompound fromItemTag(ItemStack stack) { checkItemStack(stack); Object nms = getFieldValue(get().CRAFT_HANDLE, stack); Object tag = getFieldValue(get().STACK_TAG, nms); // Create the tag if it doesn't exist if (tag == null) { NbtCompound compound = createCompound(); setItemTag(stack, compound); return compound; } return fromCompound(tag); } /** * Retrieve a CraftItemStack version of the stack. * @param stack - the stack to convert. * @return The CraftItemStack version. */ public static ItemStack getCraftItemStack(ItemStack stack) { // Any need to convert? if (stack == null || get().CRAFT_STACK.isAssignableFrom(stack.getClass())) return stack; try { // Call the private constructor Constructor<?> caller = INSTANCE.CRAFT_STACK.getDeclaredConstructor(ItemStack.class); caller.setAccessible(true); return (ItemStack) caller.newInstance(stack); } catch (Exception e) { throw new IllegalStateException("Unable to convert " + stack + " + to a CraftItemStack."); } } /** * Ensure that the given stack can store arbitrary NBT information. * @param stack - the stack to check. */ private static void checkItemStack(ItemStack stack) { if (stack == null) throw new IllegalArgumentException("Stack cannot be NULL."); if (!get().CRAFT_STACK.isAssignableFrom(stack.getClass())) throw new IllegalArgumentException("Stack must be a CraftItemStack."); if (stack.getType() == Material.AIR) throw new IllegalArgumentException("ItemStacks representing air cannot store NMS information."); } /** * Convert wrapped List and Map objects into their respective NBT counterparts. * @param name - the name of the NBT element to create. * @param value - the value of the element to create. Can be a List or a Map. * @return The NBT element. */ private Object unwrapValue(Object value) { if (value == null) return null; if (value instanceof Wrapper) { return ((Wrapper) value).getHandle(); } else if (value instanceof List) { throw new IllegalArgumentException("Can only insert a WrappedList."); } else if (value instanceof Map) { throw new IllegalArgumentException("Can only insert a WrappedCompound."); } else { return createNbtTag(getPrimitiveType(value), value); } } /** * Convert a given NBT element to a primitive wrapper or List/Map equivalent. * <p> * All changes to any mutable objects will be reflected in the underlying NBT element(s). * @param nms - the NBT element. * @return The wrapper equivalent. */ private Object wrapNative(Object nms) { if (nms == null) return null; if (BASE_CLASS.isAssignableFrom(nms.getClass())) { final NbtType type = getNbtType(nms); // Handle the different types switch (type) { case TAG_COMPOUND: return new NbtCompound(nms); case TAG_LIST: return new NbtList(nms); default: return getFieldValue(getDataField(type, nms), nms); } } throw new IllegalArgumentException("Unexpected type: " + nms); } /** * Construct a new NMS NBT tag initialized with the given value. * @param type - the NBT type. * @param value - the value, or NULL to keep the original value. * @return The created tag. */ private Object createNbtTag(NbtType type, Object value) { Object tag = invokeMethod(NBT_CREATE_TAG, null, (byte) type.id); if (value != null) { setFieldValue(getDataField(type, tag), tag, value); } return tag; } /** * Retrieve the field where the NBT class stores its value. * @param type - the NBT type. * @param nms - the NBT class instance. * @return The corresponding field. */ private Field getDataField(NbtType type, Object nms) { if (DATA_FIELD[type.id] == null) DATA_FIELD[type.id] = getField(nms, null, type.getFieldName()); return DATA_FIELD[type.id]; } /** * Retrieve the NBT type from a given NMS NBT tag. * @param nms - the native NBT tag. * @return The corresponding type. */ private NbtType getNbtType(Object nms) { int type = (Byte) invokeMethod(NBT_GET_TYPE, nms); return NBT_ENUM.get(type); } /** * Retrieve the nearest NBT type for a given primitive type. * @param primitive - the primitive type. * @return The corresponding type. */ private NbtType getPrimitiveType(Object primitive) { NbtType type = NBT_ENUM.get(NBT_CLASS.inverse().get(Primitives.unwrap(primitive.getClass()))); // Display the illegal value at least if (type == null) throw new IllegalArgumentException( String.format("Illegal type: %s (%s)", primitive.getClass(), primitive)); return type; } /** * Invoke a method on the given target instance using the provided parameters. * @param method - the method to invoke. * @param target - the target. * @param params - the parameters to supply. * @return The result of the method. */ private static Object invokeMethod(Method method, Object target, Object... params) { try { return method.invoke(target, params); } catch (Exception e) { throw new RuntimeException("Unable to invoke method " + method + " for " + target, e); } } private static void setFieldValue(Field field, Object target, Object value) { try { field.set(target, value); } catch (Exception e) { throw new RuntimeException("Unable to set " + field + " for " + target, e); } } private static Object getFieldValue(Field field, Object target) { try { return field.get(target); } catch (Exception e) { throw new RuntimeException("Unable to retrieve " + field + " for " + target, e); } } /** * Search for the first publically and privately defined method of the given name and parameter count. * @param requireMod - modifiers that are required. * @param bannedMod - modifiers that are banned. * @param clazz - a class to start with. * @param methodName - the method name, or NULL to skip. * @param params - the expected parameters. * @return The first method by this name. * @throws IllegalStateException If we cannot find this method. */ private static Method getMethod(int requireMod, int bannedMod, Class<?> clazz, String methodName, Class<?>... params) { for (Method method : clazz.getDeclaredMethods()) { // Limitation: Doesn't handle overloads if ((method.getModifiers() & requireMod) == requireMod && (method.getModifiers() & bannedMod) == 0 && (methodName == null || method.getName().equals(methodName)) && Arrays.equals(method.getParameterTypes(), params)) { method.setAccessible(true); return method; } } // Search in every superclass if (clazz.getSuperclass() != null) return getMethod(requireMod, bannedMod, clazz.getSuperclass(), methodName, params); throw new IllegalStateException( String.format("Unable to find method %s (%s).", methodName, Arrays.asList(params))); } /** * Search for the first publically and privately defined field of the given name. * @param instance - an instance of the class with the field. * @param clazz - an optional class to start with, or NULL to deduce it from instance. * @param fieldName - the field name. * @return The first field by this name. * @throws IllegalStateException If we cannot find this field. */ private static Field getField(Object instance, Class<?> clazz, String fieldName) { if (clazz == null) clazz = instance.getClass(); // Ignore access rules for (Field field : clazz.getDeclaredFields()) { if (field.getName().equals(fieldName)) { field.setAccessible(true); return field; } } // Recursively fild the correct field if (clazz.getSuperclass() != null) return getField(instance, clazz.getSuperclass(), fieldName); throw new IllegalStateException("Unable to find field " + fieldName + " in " + instance); } /** * Represents a class for caching wrappers. * @author Kristian */ private final class CachedNativeWrapper { // Don't recreate wrapper objects private final ConcurrentMap<Object, Object> cache = new MapMaker().weakKeys().makeMap(); public Object wrap(Object value) { Object current = cache.get(value); if (current == null) { current = wrapNative(value); // Only cache composite objects if (current instanceof ConvertedMap || current instanceof ConvertedList) { cache.put(value, current); } } return current; } } /** * Represents a map that wraps another map and automatically * converts entries of its type and another exposed type. * @author Kristian */ private class ConvertedMap extends AbstractMap<String, Object> implements Wrapper { private final Object handle; private final Map<String, Object> original; private final CachedNativeWrapper cache = new CachedNativeWrapper(); public ConvertedMap(Object handle, Map<String, Object> original) { this.handle = handle; this.original = original; } // For converting back and forth protected Object wrapOutgoing(Object value) { return cache.wrap(value); } protected Object unwrapIncoming(Object wrapped) { return unwrapValue(wrapped); } // Modification @Override public Object put(String key, Object value) { return wrapOutgoing(original.put((String) key, unwrapIncoming(value))); } // Performance @Override public Object get(Object key) { return wrapOutgoing(original.get(key)); } @Override public Object remove(Object key) { return wrapOutgoing(original.remove(key)); } @Override public boolean containsKey(Object key) { return original.containsKey(key); } @Override public Set<Entry<String, Object>> entrySet() { return new AbstractSet<Entry<String, Object>>() { @Override public boolean add(Entry<String, Object> e) { String key = e.getKey(); Object value = e.getValue(); original.put(key, unwrapIncoming(value)); return true; } @Override public int size() { return original.size(); } @Override public Iterator<Entry<String, Object>> iterator() { return ConvertedMap.this.iterator(); } }; } private Iterator<Entry<String, Object>> iterator() { final Iterator<Entry<String, Object>> proxy = original.entrySet().iterator(); return new Iterator<Entry<String, Object>>() { @Override public boolean hasNext() { return proxy.hasNext(); } @Override public Entry<String, Object> next() { Entry<String, Object> entry = proxy.next(); return new SimpleEntry<String, Object>(entry.getKey(), wrapOutgoing(entry.getValue())); } @Override public void remove() { proxy.remove(); } }; } @Override public Object getHandle() { return handle; } } /** * Represents a list that wraps another list and converts elements * of its type and another exposed type. * @author Kristian */ private class ConvertedList extends AbstractList<Object> implements Wrapper { private final Object handle; private final List<Object> original; private final CachedNativeWrapper cache = new CachedNativeWrapper(); public ConvertedList(Object handle, List<Object> original) { if (NBT_LIST_TYPE == null) NBT_LIST_TYPE = getField(handle, null, "type"); this.handle = handle; this.original = original; } protected Object wrapOutgoing(Object value) { return cache.wrap(value); } protected Object unwrapIncoming(Object wrapped) { return unwrapValue(wrapped); } @Override public Object get(int index) { return wrapOutgoing(original.get(index)); } @Override public int size() { return original.size(); } @Override public Object set(int index, Object element) { return wrapOutgoing(original.set(index, unwrapIncoming(element))); } @Override public void add(int index, Object element) { Object nbt = unwrapIncoming(element); // Set the list type if its the first element if (size() == 0) setFieldValue(NBT_LIST_TYPE, handle, (byte) getNbtType(nbt).id); original.add(index, nbt); } @Override public Object remove(int index) { return wrapOutgoing(original.remove(index)); } @Override public boolean remove(Object o) { return original.remove(unwrapIncoming(o)); } @Override public Object getHandle() { return handle; } } }