org.waveprotocol.box.server.persistence.migration.DeltaMigrator.java Source code

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Here is the source code for org.waveprotocol.box.server.persistence.migration.DeltaMigrator.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.waveprotocol.box.server.persistence.migration;

import com.google.common.collect.ImmutableSet;

import org.waveprotocol.box.common.ExceptionalIterator;
import org.waveprotocol.box.server.persistence.PersistenceException;
import org.waveprotocol.box.server.waveserver.DeltaStore;
import org.waveprotocol.box.server.waveserver.DeltaStore.DeltasAccess;
import org.waveprotocol.box.server.waveserver.WaveletDeltaRecord;
import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.id.WaveletId;
import org.waveprotocol.wave.model.id.WaveletName;
import org.waveprotocol.wave.model.version.HashedVersion;
import org.waveprotocol.wave.util.logging.Log;

import java.io.IOException;
import java.util.ArrayList;

/**
 *
 * An utility class to copy all deltas between storages. Already existing Waves
 * in the target store wont be changed.
 *
 * It is NOT an incremental process.
 *
 * @author pablojan@gmail.com (Pablo Ojanguren)
 *
 */
public class DeltaMigrator {

    private static final Log LOG = Log.get(DeltaMigrator.class);

    protected DeltaStore sourceStore = null;
    protected DeltaStore targetStore = null;

    public DeltaMigrator(DeltaStore sourceStore, DeltaStore targetStore) {
        this.sourceStore = sourceStore;
        this.targetStore = targetStore;
    }

    public void run() {

        LOG.info("Starting Wave migration from " + sourceStore.getClass().getSimpleName() + " to "
                + targetStore.getClass().getSimpleName());

        long startTime = System.currentTimeMillis();

        try {

            ExceptionalIterator<WaveId, PersistenceException> srcItr = sourceStore.getWaveIdIterator();

            // Waves
            while (srcItr.hasNext()) {

                WaveId waveId = srcItr.next();

                ImmutableSet<WaveletId> waveletIds = sourceStore.lookup(waveId);

                if (!targetStore.lookup(waveId).isEmpty()) {
                    LOG.info("Skipping Wave because it's found in target store : " + waveId.toString());
                    continue;
                }

                LOG.info("Migrating Wave : " + waveId.toString() + " with " + waveletIds.size() + " wavelets");

                int waveletsTotal = waveletIds.size();
                int waveletsCount = 0;

                // Wavelets
                for (WaveletId waveletId : waveletIds) {

                    waveletsCount++;

                    LOG.info("Migrating wavelet " + waveletsCount + "/" + waveletsTotal + " : "
                            + waveletId.toString());

                    DeltasAccess sourceDeltas = sourceStore.open(WaveletName.of(waveId, waveletId));
                    DeltasAccess targetDeltas = targetStore.open(WaveletName.of(waveId, waveletId));

                    // Get all deltas from last version to initial version (0): reverse
                    // order
                    int deltasCount = 0;

                    ArrayList<WaveletDeltaRecord> deltas = new ArrayList<WaveletDeltaRecord>();
                    HashedVersion deltaResultingVersion = sourceDeltas.getEndVersion();

                    // Deltas
                    while (deltaResultingVersion != null && deltaResultingVersion.getVersion() != 0) {
                        deltasCount++;
                        WaveletDeltaRecord deltaRecord = sourceDeltas
                                .getDeltaByEndVersion(deltaResultingVersion.getVersion());
                        deltas.add(deltaRecord);
                        // get the previous delta, this is the appliedAt
                        deltaResultingVersion = deltaRecord.getAppliedAtVersion();
                    }
                    LOG.info("Appending " + deltasCount + "deltas to target");
                    targetDeltas.append(deltas);
                }
            } // While Waves

            long endTime = System.currentTimeMillis();

            LOG.info("Migration completed. Total time = " + (endTime - startTime) + "ms");

        } catch (PersistenceException e) {

            throw new RuntimeException(e);

        } catch (IOException e) {

            throw new RuntimeException(e);

        }

    }

}