/**
* Copyright 2010 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 org.waveprotocol.box.server.persistence.memory;
import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;
import com.google.protobuf.InvalidProtocolBufferException;
import org.waveprotocol.box.server.waveserver.ByteStringMessage;
import org.waveprotocol.box.server.waveserver.WaveletDeltaRecord;
import org.waveprotocol.box.server.waveserver.DeltaStore.DeltasAccess;
import org.waveprotocol.wave.federation.Proto.ProtocolAppliedWaveletDelta;
import org.waveprotocol.wave.model.id.WaveletName;
import org.waveprotocol.wave.model.operation.wave.TransformedWaveletDelta;
import org.waveprotocol.wave.model.version.HashedVersion;
import java.util.Collection;
import java.util.Map;
/**
* An in-memory implementation of DeltasAccess
*
* @author josephg@google.com (Joseph Gentle)
*/
public class MemoryDeltaCollection implements DeltasAccess {
private final Map<Long, WaveletDeltaRecord> deltas = Maps.newHashMap();
private final Map<Long, WaveletDeltaRecord> endDeltas = Maps.newHashMap();
private final WaveletName waveletName;
private HashedVersion endVersion = null;
public MemoryDeltaCollection(WaveletName waveletName) {
Preconditions.checkNotNull(waveletName);
this.waveletName = waveletName;
}
@Override
public boolean isEmpty() {
return deltas.isEmpty();
}
@Override
public WaveletName getWaveletName() {
return waveletName;
}
@Override
public HashedVersion getEndVersion() {
return endVersion;
}
@Override
public WaveletDeltaRecord getDelta(long version) {
return deltas.get(version);
}
@Override
public WaveletDeltaRecord getDeltaByEndVersion(long version) {
return endDeltas.get(version);
}
@Override
public HashedVersion getAppliedAtVersion(long version) throws InvalidProtocolBufferException {
WaveletDeltaRecord delta = getDelta(version);
return (delta != null) ? delta.getAppliedAtVersion() : null;
}
@Override
public HashedVersion getResultingVersion(long version) {
WaveletDeltaRecord delta = getDelta(version);
return (delta != null) ? delta.transformed.getResultingVersion() : null;
}
@Override
public ByteStringMessage<ProtocolAppliedWaveletDelta> getAppliedDelta(long version) {
WaveletDeltaRecord delta = getDelta(version);
return (delta != null) ? delta.applied : null;
}
@Override
public TransformedWaveletDelta getTransformedDelta(long version) {
WaveletDeltaRecord delta = getDelta(version);
return (delta != null) ? delta.transformed : null;
}
@Override
public void close() {
// Does nothing.
}
@Override
public void append(Collection<WaveletDeltaRecord> newDeltas) {
for (WaveletDeltaRecord delta : newDeltas) {
// Before: ... | D |
// start end
// After: ... | D | D + 1 |
// start end
long startVersion = delta.transformed.getAppliedAtVersion();
Preconditions.checkState(
(startVersion == 0 && endVersion == null) ||
(startVersion == endVersion.getVersion()));
deltas.put(startVersion, delta);
endVersion = delta.transformed.getResultingVersion();
endDeltas.put(endVersion.getVersion(), delta);
}
}
}