eu.numberfour.n4js.resource.OrderedResourceDescriptionsData.java Source code

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Here is the source code for eu.numberfour.n4js.resource.OrderedResourceDescriptionsData.java

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/**
 * Copyright (c) 2016 NumberFour AG.
 * 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:
 *   NumberFour AG - Initial API and implementation
 */
package eu.numberfour.n4js.resource;

import java.util.Map;
import java.util.Set;

import org.eclipse.xtext.naming.QualifiedName;
import org.eclipse.xtext.resource.IEObjectDescription;
import org.eclipse.xtext.resource.IResourceDescription;
import org.eclipse.xtext.resource.IResourceDescriptions;
import org.eclipse.xtext.resource.impl.ResourceDescriptionsData;

import com.google.common.collect.Sets;

/**
 * Customized {@link ResourceDescriptionsData} implementation that keeps the order of indexed elements (
 * {@link IEObjectDescription}) if multiple instances can be associated with the same {@link QualifiedName}.
 */
public class OrderedResourceDescriptionsData extends ResourceDescriptionsData {

    /**
     * Creates a new {@link IResourceDescriptions} implementation that keeps the order of the indexed elements (
     * {@link IEObjectDescription}) if more the one elements belong to the same {@link QualifiedName qualified name}.
     *
     * @param descriptions
     *            the initial subset of {@link IResourceDescription resource description} instances.
     */
    public OrderedResourceDescriptionsData(final Iterable<IResourceDescription> descriptions) {
        super(descriptions);
    }

    @SuppressWarnings("unchecked")
    @Override
    protected void registerDescription(final IResourceDescription description,
            final Map<QualifiedName, Object> target) {

        for (final IEObjectDescription object : description.getExportedObjects()) {
            final QualifiedName lowerCase = object.getName().toLowerCase();
            final Object existing = target.put(lowerCase, description);
            if (existing != null && existing != description) {
                Set<IResourceDescription> set = null;
                if (existing instanceof IResourceDescription) {
                    // The linked hash set is the difference comparing to the super class.
                    set = Sets.newLinkedHashSetWithExpectedSize(2);
                    set.add((IResourceDescription) existing);
                } else {
                    set = (Set<IResourceDescription>) existing;
                }
                set.add(description);
                target.put(lowerCase, set);
            }
        }
    }

}