package org.apache.tika.io.json;
/*
* 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.lang.reflect.Type;
import java.util.Arrays;
import org.apache.tika.metadata.Metadata;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
public class JsonMetadataSerializer implements JsonSerializer<Metadata> {
/**
*
* @param metadata
* @param type
* @param context
* @return JsonObject with key/value(s) pairs or JsonNull if metadata is null.
*/
@Override
public JsonElement serialize(Metadata metadata, Type type, JsonSerializationContext context) {
if (metadata == null){
return new JsonNull();
}
String[] names = getNames(metadata);
if (names == null) {
return new JsonNull();
}
JsonObject root = new JsonObject();
for (String n : names) {
String[] vals = metadata.getValues(n);
if (vals == null) {
//silently skip?
continue;
}
if (vals.length == 1) {
root.addProperty(n, vals[0]);
} else {
JsonArray jArr = new JsonArray();
for (int i = 0; i < vals.length; i++) {
jArr.add(new JsonPrimitive(vals[i]));
}
root.add(n, jArr);
}
}
return root;
}
/**
* Override to get a custom sort order
* or to filter names.
*
* @param metadata
* @return
*/
protected String[] getNames(Metadata metadata) {
String[] names = metadata.names();
Arrays.sort(names);
return names;
}
}