/*
* Copyright 2014 Pnambic Computing
*
* 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 com.google.devtools.depan.eclipse.persist;
import com.google.devtools.depan.eclipse.plugins.SourcePlugin;
import com.google.devtools.depan.eclipse.plugins.SourcePluginRegistry;
import com.google.devtools.depan.model.RelationshipSet;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
/**
* {@code XStream} converter to handle {@code RelationshipSet}s.
* In order to facilitate selection, etc., make sure that all built-in
* relation sets use the same instance.
*
* TODO: Provide a real relation set registry that include user defined
* relation sets to avoid aliases and duplicate definitions.
*
* @author <a href="mailto:leeca@google.com">Lee Carver</a>
*/
public class RelSetConverter implements Converter {
private static final String RELATION_SET_TAG = "relation-set";
// Attribute names
private static final String REL_SET = "rel-set";
private static final String PLUGIN_ID = "plugin-id";
public RelSetConverter() {
}
public static void configXStream(XStream xstream) {
xstream.aliasType(RELATION_SET_TAG, RelSetConverter.class);
xstream.registerConverter(new RelSetConverter());
}
@Override
@SuppressWarnings("rawtypes") // Parent type uses raw type Class
public boolean canConvert(Class type) {
return RelationshipSet.class.isAssignableFrom(type);
}
@Override
public void marshal(Object source, HierarchicalStreamWriter writer,
MarshallingContext context) {
RelationshipSet relSet = (RelationshipSet) source;
SourcePlugin plugin = findBuiltIn(relSet);
if (null != plugin) {
String entryId = SourcePluginRegistry.getInstance().getPluginId(plugin);
writer.addAttribute(PLUGIN_ID, entryId);
writer.addAttribute(REL_SET, relSet.getName());
}
}
@Override
public Object unmarshal(HierarchicalStreamReader reader,
UnmarshallingContext context) {
try {
String pluginId = reader.getAttribute(PLUGIN_ID);
String relSetName = reader.getAttribute(REL_SET);
if ((null != pluginId) && (null != relSetName)) {
SourcePlugin plugin = SourcePluginRegistry.getSourcePlugin(pluginId);
if (null == plugin) {
return null;
}
for (RelationshipSet builtIn : plugin.getBuiltinRelationshipSets()) {
if (relSetName.equals(builtIn.getName())) {
return builtIn;
}
}
}
return null;
} catch (RuntimeException err) {
err.printStackTrace();
throw err;
}
}
private SourcePlugin findBuiltIn(RelationshipSet relSet) {
// Populate the list viewer with all known relations.
for (SourcePlugin plugin : SourcePluginRegistry.getInstances()) {
for (RelationshipSet builtIn : plugin.getBuiltinRelationshipSets()) {
if (builtIn == relSet) {
return plugin;
}
}
}
return null;
}
}