/*
* Copyright 2009 Google Inc.
*
* 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.editors.GraphDocument;
import com.google.devtools.depan.eclipse.editors.GraphModelReference;
import com.google.devtools.depan.eclipse.editors.ResourceCache;
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;
import com.thoughtworks.xstream.mapper.Mapper;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;
/**
* Custom {@code XStream} converter for {@code GraphModelReference}s.
* This serializes only the file name, and reconstitutes the {@code GraphModel}
* by reading the file contents on loads.
*
* @author <a href="mailto:leeca@google.com">Lee Carver</a>
*/
public class GraphModelReferenceConverter implements Converter {
public static final String GRAPH_REF_TAG = "graph-ref";
public GraphModelReferenceConverter(Mapper mapper) {
}
@Override
@SuppressWarnings("rawtypes") // Parent type uses raw type Class
public boolean canConvert(Class type) {
return GraphModelReference.class.equals(type);
}
/**
* Simply output the workspace relative name for the referenced GraphModel.
*/
@Override
public void marshal(Object source, HierarchicalStreamWriter writer,
MarshallingContext context) {
GraphModelReference graphRef = (GraphModelReference) source;
context.convertAnother(graphRef.getLocation().getFullPath().toString());
}
/**
* {@inheritDoc}
* <p>
* This implementation reads in the workspace-relative name of the dependency
* graph file, and then tries to load that file as the graph model.
*
* @see EdgeConverter#unmarshal(HierarchicalStreamReader, UnmarshallingContext)
*/
@Override
public Object unmarshal(
HierarchicalStreamReader reader, UnmarshallingContext context) {
IFile graphFile = unmarshallGraphLocation(context);
GraphDocument graph = ResourceCache.fetchGraphDocument(graphFile);
return new GraphModelReference(graphFile, graph);
}
/**
* @param graphPath
* @return
*/
private IFile unmarshallGraphLocation(UnmarshallingContext context) {
String graphPath = (String) context.convertAnother(null, String.class);
if (null == graphPath) {
throw new RuntimeException("Missing location for dependencies");
}
IResource graphRsrc = ResourcesPlugin.getWorkspace().getRoot()
.findMember(graphPath);
if (null == graphRsrc) {
throw new RuntimeException(
"Can't locate resource " + graphPath + " for dependency information");
}
if (!(graphRsrc instanceof IFile)) {
throw new RuntimeException("Resource " + graphPath + " is not a file");
}
return (IFile) graphRsrc;
}
}