/**
* 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.wave.model.wave.undo;
import org.waveprotocol.wave.model.operation.wave.AddParticipant;
import org.waveprotocol.wave.model.operation.wave.NoOp;
import org.waveprotocol.wave.model.operation.wave.RemoveParticipant;
import org.waveprotocol.wave.model.operation.wave.VersionUpdateOp;
import org.waveprotocol.wave.model.operation.wave.WaveletBlipOperation;
import org.waveprotocol.wave.model.operation.wave.WaveletOperation;
/**
* Utility methods.
*
*/
final class OpUtils {
private OpUtils() {
}
/**
* Returns true iff the wavelet operation is considered a no-op as far as undo
* is concerned.
*
* @param op
*/
static boolean isNoop(WaveletOperation op) {
if (op instanceof VersionUpdateOp || op instanceof NoOp) {
return true;
} else if (op instanceof AddParticipant || op instanceof RemoveParticipant
|| op instanceof WaveletBlipOperation) {
return false;
} else {
// This happens when the op parameter is a non-core subclass of
// WaveletOperation, not supported by wave.
throw new RuntimeException("Unhandled op:" + op.getClass());
}
}
}