Java tutorial
/* * Copyright 2014 MovingBlocks * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.terasology.logic.behavior.asset; import com.google.common.base.Charsets; import com.google.common.collect.Maps; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.JsonSyntaxException; import com.google.gson.TypeAdapter; import com.google.gson.TypeAdapterFactory; import com.google.gson.reflect.TypeToken; import com.google.gson.stream.JsonReader; import com.google.gson.stream.JsonToken; import com.google.gson.stream.JsonWriter; import org.terasology.utilities.Assets; import org.terasology.assets.ResourceUrn; import org.terasology.assets.format.AbstractAssetFileFormat; import org.terasology.assets.format.AssetDataFile; import org.terasology.assets.module.annotations.RegisterAssetFileFormat; import org.terasology.engine.ComponentFieldUri; import org.terasology.logic.behavior.tree.LookupNode; import org.terasology.logic.behavior.tree.Node; import org.terasology.reflection.metadata.ClassMetadata; import org.terasology.registry.CoreRegistry; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.NotSerializableException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.util.List; import java.util.Map; /** * Loader for behavior assets. Can also save assets into json format. * <br><br> * If there are both, Nodes and Renderables tree, both are loaded/saved. To ensure, the nodes get associated to * the correct renderable, additional ids are introduced (only in the json file). * <br><br> * */ @RegisterAssetFileFormat public class BehaviorTreeFormat extends AbstractAssetFileFormat<BehaviorTreeData> { private BehaviorTreeGson treeGson = new BehaviorTreeGson(); public BehaviorTreeFormat() { super("behavior"); } public void save(OutputStream stream, BehaviorTreeData data) throws IOException { try (JsonWriter write = new JsonWriter(new OutputStreamWriter(stream, Charsets.UTF_8))) { write.setIndent(" "); write.beginObject().name("model"); treeGson.saveTree(write, data.getRoot()); write.endObject(); } } @Override public BehaviorTreeData load(ResourceUrn resourceUrn, List<AssetDataFile> list) throws IOException { NodesClassLibrary nodesClassLibrary = CoreRegistry.get(NodesClassLibrary.class); if (nodesClassLibrary == null) { throw new IOException("Could not load behavior tree, NodeClassLibrary not available"); } try (InputStream stream = list.get(0).openStream()) { return load(stream); } } public BehaviorTreeData load(InputStream stream) throws IOException { BehaviorTreeData data = new BehaviorTreeData(); try (JsonReader reader = new JsonReader(new InputStreamReader(stream, Charsets.UTF_8))) { reader.setLenient(true); reader.beginObject(); nextName(reader, "model"); data.setRoot(treeGson.loadTree(reader)); reader.endObject(); } catch (JsonSyntaxException e) { throw new IOException("Cannot load tree! " + e.getMessage(), e); } return data; } private String nextName(JsonReader in, String expectedName) throws IOException { String name = in.nextName(); if (!expectedName.equals(name)) { throw new RuntimeException(expectedName + " expected!"); } return name; } private final class BehaviorTreeGson { private int currentId; private Map<Node, Integer> nodeIds = Maps.newHashMap(); private Map<Integer, Node> idNodes = Maps.newHashMap(); private Gson gsonNode; private BehaviorTreeGson() { gsonNode = new GsonBuilder().setPrettyPrinting() .registerTypeAdapterFactory(new NodeTypeAdapterFactory()) .registerTypeAdapter(BehaviorTree.class, new BehaviorTreeTypeAdapterFactory()) .registerTypeAdapter(ComponentFieldUri.class, new ComponentFieldUriAdapterFactory()).create(); } public Node loadTree(JsonReader reader) { resetIds(); return gsonNode.fromJson(reader, Node.class); } public void saveTree(JsonWriter writer, Node root) { resetIds(); gsonNode.toJson(root, Node.class, writer); } public Node getNode(int id) { return idNodes.get(id); } public int getId(Node node) { return nodeIds.get(node); } private void resetIds() { idNodes.clear(); nodeIds.clear(); currentId = 0; } private class NodeTypeAdapterFactory implements TypeAdapterFactory { @Override public <T> TypeAdapter<T> create(final Gson gson, TypeToken<T> type) { final TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type); return new TypeAdapter<T>() { private NodesClassLibrary nodesClassLibrary = CoreRegistry.get(NodesClassLibrary.class); @Override public void write(JsonWriter out, T value) throws IOException { if (value instanceof Node) { Node node = (Node) value; ClassMetadata<?, ?> metadata = nodesClassLibrary.getMetadata(node.getClass()); if (metadata != null) { out.beginObject(); idNodes.put(currentId, node); nodeIds.put(node, currentId); TypeAdapter<T> delegateAdapter = getDelegateAdapter(value.getClass()); String metadataVal = metadata.getUri().toString(); out.name("nodeType").value(metadataVal).name("nodeId").value(currentId); currentId++; out.name("node"); delegateAdapter.write(out, value); out.endObject(); } else { delegate.write(out, null); } } else { delegate.write(out, value); } } @Override public T read(JsonReader in) throws IOException { if (in.peek() == JsonToken.BEGIN_OBJECT) { in.beginObject(); nextName(in, "nodeType"); String nodeType = in.nextString(); ClassMetadata<? extends Node, ?> classMetadata = CoreRegistry .get(NodesClassLibrary.class).resolve(nodeType); nextName(in, "nodeId"); int id = in.nextInt(); nextName(in, "node"); if (classMetadata != null) { TypeAdapter<T> delegateAdapter = getDelegateAdapter(classMetadata.getType()); Node result; if (classMetadata.getType() == LookupNode.class) { result = classMetadata.newInstance(); in.beginObject(); nextName(in, "tree"); String uri = in.nextString(); ((LookupNode) result).tree = Assets.get(uri, BehaviorTree.class).orElse(null); in.endObject(); } else { result = (Node) delegateAdapter.read(in); } idNodes.put(id, result); nodeIds.put(result, id); in.endObject(); return (T) result; } else { throw new NotSerializableException(nodeType); } } else { return delegate.read(in); } } private TypeAdapter<T> getDelegateAdapter(Class<?> cls) { return (TypeAdapter<T>) gson.getDelegateAdapter(NodeTypeAdapterFactory.this, TypeToken.get(cls)); } }; } } private class BehaviorTreeTypeAdapterFactory extends TypeAdapter<BehaviorTree> { @Override public void write(JsonWriter out, BehaviorTree value) throws IOException { if (value == null) { out.value(""); } else { out.value(value.getUrn().toString()); } } @Override public BehaviorTree read(JsonReader in) throws IOException { String uri = in.nextString(); if (uri != null && uri.length() > 0) { return Assets.get(in.nextString(), BehaviorTree.class).orElse(null); } else { return null; } } } private class ComponentFieldUriAdapterFactory extends TypeAdapter<ComponentFieldUri> { @Override public void write(JsonWriter out, ComponentFieldUri value) throws IOException { if (value == null) { out.value(""); } else { out.value(value.toString()); } } @Override public ComponentFieldUri read(JsonReader in) throws IOException { String uri = in.nextString(); if (uri != null && uri.length() > 0) { return new ComponentFieldUri(uri); } else { return null; } } } } }