org.eclipse.emf.compare.ide.utils.StorageURIConverter.java Source code

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Here is the source code for org.eclipse.emf.compare.ide.utils.StorageURIConverter.java

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/*******************************************************************************
 * Copyright (c) 2011, 2015 Obeo.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.emf.compare.ide.utils;

import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.eclipse.core.resources.IStorage;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.compare.ide.internal.utils.URIStorage;
import org.eclipse.emf.compare.utils.DelegatingURIConverter;
import org.eclipse.emf.ecore.resource.URIConverter;
import org.eclipse.emf.ecore.resource.URIHandler;

/**
 * This implementation of an URI converter will keep track of the storages from which it created input
 * streams.
 * 
 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 */
public class StorageURIConverter extends DelegatingURIConverter {
    /** Keeps references towards the revisions that we've loaded through this URI converter. */
    private Set<IStorage> loadedRevisions;

    /**
     * Constructs our uri converter given its delegate.
     * 
     * @param delegate
     *            The delegate URI Converter.
     */
    public StorageURIConverter(URIConverter delegate) {
        super(delegate);
        this.loadedRevisions = Sets.newSetFromMap(new ConcurrentHashMap<IStorage, Boolean>());
    }

    /**
     * Allows clients of this API to retrieve the set of revisions that were loaded while resolving the
     * resource set on which this converter is installed.
     * 
     * @return The set of revisions loaded through this converter.
     */
    public Set<IStorage> getLoadedRevisions() {
        return loadedRevisions;
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.eclipse.emf.compare.utils.DelegatingURIConverter#createInputStream(org.eclipse.emf.common.util.URI,
     *      java.util.Map)
     */
    @Override
    public InputStream createInputStream(URI uri, Map<?, ?> options) throws IOException {
        final URI normalizedURI = normalize(uri);
        final URIHandler handler = getURIHandler(normalizedURI);
        // Only keep track of the loaded resource if it's a platform:/resource.
        // Resources loaded from plugins don't need to be part of our final logical model.
        if (uri.isPlatformResource()) {
            getLoadedRevisions().add(createStorage(uri, handler, this));
        }

        final Map<Object, Object> actualOptions = Maps.newLinkedHashMap();
        actualOptions.put(URIConverter.OPTION_URI_CONVERTER, this);
        if (options != null) {
            actualOptions.putAll(options);
        }
        return handler.createInputStream(normalizedURI, actualOptions);
    }

    /**
     * Creates a new IStorage for the given URI.
     * 
     * @param uri
     *            The uri for which we need a storage.
     * @param handler
     *            The URI handler that can be used to retrieve this URI's contents.
     * @param converter
     *            The URI converter from which this storage was created.
     * @return The newly created IStorage.
     */
    protected IStorage createStorage(URI uri, URIHandler handler, URIConverter converter) {
        return new URIStorage(uri, handler, converter);
    }
}