/*
* 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.
*/
package org.apache.shindig.protocol.conversion.xstream;
import java.util.Map;
import java.util.Map.Entry;
import com.google.common.collect.MapMaker;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.mapper.Mapper;
/**
* converts a map to and from the form <container>
* <key>value</key> <key>value</key> <container>.
*/
public class MapConverter extends AbstractCollectionConverter {
/**
* Create a MapConverter that use use the supplied mapper.
*
* @param mapper
* the mapped to base the conversion on.
*/
public MapConverter(Mapper mapper) {
super(mapper);
}
/**
* output the Map in the simplified form.
*
* @param source
* the object to be output
* @param writer
* the writer to use to perform the output.
* @param context
* the context in which to perform the output.
*
* @see com.thoughtworks.xstream.converters.Converter#marshal(java.lang.Object,
* com.thoughtworks.xstream.io.HierarchicalStreamWriter,
* com.thoughtworks.xstream.converters.MarshallingContext)
*/
@Override
public void marshal(Object source, HierarchicalStreamWriter writer,
MarshallingContext context) {
Map<?, ?> map = (Map<?, ?>) source;
for (Entry<?, ?> e : map.entrySet()) {
writer.startNode("entry");
writer.startNode("key");
writer.setValue(String.valueOf(e.getKey()));
writer.endNode();
writer.startNode("value");
context.convertAnother(e.getValue());
writer.endNode();
writer.endNode();
}
}
/**
* Convert a suitably positioned reader stream into a Map object.
*
* @param reader
* the stream reader positioned at the start of the object.
* @param context
* the unmarshalling context.
* @return the object representing the stream.
* @see com.thoughtworks.xstream.converters.Converter#unmarshal(com.thoughtworks.xstream.io.HierarchicalStreamReader,
* com.thoughtworks.xstream.converters.UnmarshallingContext)
*/
@Override
public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
Map<String, Object> m = new MapMaker().makeMap();
reader.moveDown();
while (reader.hasMoreChildren()) {
String key = reader.getNodeName();
if ("entry".equals(key)) {
Object value = null;
reader.moveDown();
String type = reader.getNodeName();
if ("key".equals(type)) {
key = reader.getValue();
} else {
if (reader.hasMoreChildren()) {
value = readItem(reader, context, m);
} else {
value = reader.getValue();
}
}
reader.moveUp();
reader.moveDown();
type = reader.getNodeName();
if ("key".equals(type)) {
key = reader.getValue();
} else {
if (reader.hasMoreChildren()) {
value = readItem(reader, context, m);
} else {
value = reader.getValue();
}
}
m.put(key, value);
reader.moveUp();
} else {
reader.moveDown();
if (reader.hasMoreChildren()) {
m.put(key, readItem(reader, context, m));
} else {
m.put(key, reader.getValue());
}
reader.moveUp();
}
}
reader.moveUp();
return m;
}
/**
* Can this Converter convert the type supplied.
*
* @param clazz
* the type being converted.
* @return true if the type supplied is a form of Map.
* @see com.thoughtworks.xstream.converters.ConverterMatcher#canConvert(java.lang.Class)
*/
@Override
@SuppressWarnings("unchecked")
// API is not generic
public boolean canConvert(Class clazz) {
return Map.class.isAssignableFrom(clazz);
}
}