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 *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *  This code is free software; you can redistribute it and/or modify it
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 *  published by the Free Software Foundation.  Oracle designates this
 *  particular file as subject to the "Classpath" exception as provided
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 * 
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 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  version 2 for more details (a copy is included in the LICENSE file that
 *  accompanied this code).
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package org.graalvm.visualvm.core.snapshot;

import org.graalvm.visualvm.core.datasource.DataSource;
import org.graalvm.visualvm.core.datasource.descriptor.DataSourceDescriptor;
import org.graalvm.visualvm.core.datasource.descriptor.DataSourceDescriptorFactory;
import org.graalvm.visualvm.core.model.AbstractModelProvider;

/**
 * Toplevel node Snapshots in Applications window.
 *
 * @author Jiri Sedlacek
 */
public final class SnapshotsContainer extends DataSource {

    private static SnapshotsContainer sharedInstance;

    /**
     * Returns singleton instance of SnapshotsContainer.
     *
     * @return singleton instance of SnapshotsContainer.
     */
    public static synchronized SnapshotsContainer sharedInstance() {
        if (sharedInstance == null) sharedInstance = new SnapshotsContainer();
        return sharedInstance;
    }


    private SnapshotsContainer() {
        DataSourceDescriptorFactory.getDefault().registerProvider(
            new AbstractModelProvider<DataSourceDescriptor,DataSource>() {
                public DataSourceDescriptor createModelFor(DataSource ds) {
                    if (SnapshotsContainer.sharedInstance().equals(ds))
                        return new SnapshotsContainerDescriptor();
                    else return null;
                }
            }
        );
        DataSource.ROOT.getRepository().addDataSource(this);
    }

}
