Java tutorial
package org.apache.tika.metadata.serialization; /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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. */ import java.util.Arrays; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import org.apache.tika.metadata.Metadata; public class JsonMetadataBase { static Gson defaultInit() { GsonBuilder builder = new GsonBuilder(); builder.registerTypeHierarchyAdapter(Metadata.class, new JsonMetadataSerializer()); builder.registerTypeHierarchyAdapter(Metadata.class, new JsonMetadataDeserializer()); return builder.create(); } static Gson prettyInit() { GsonBuilder builder = new GsonBuilder(); builder.registerTypeHierarchyAdapter(Metadata.class, new SortedJsonMetadataSerializer()); builder.registerTypeHierarchyAdapter(Metadata.class, new JsonMetadataDeserializer()); builder.setPrettyPrinting(); return builder.create(); } private static class SortedJsonMetadataSerializer extends JsonMetadataSerializer { @Override public String[] getNames(Metadata m) { String[] names = m.names(); Arrays.sort(names, new PrettyMetadataKeyComparator()); return names; } } }