/**
* 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.wave.model.version;
import org.waveprotocol.wave.model.util.Base64DecoderException;
import org.waveprotocol.wave.model.util.CharBase64;
import org.waveprotocol.wave.model.util.Serializer;
/**
* A serializer for wavelet hashed versions. Represents them as
* pair-encoded strings: [version]:[hash base64]
*
* @author anorth@google.com (Alex North)
*/
public final class HashedVersionSerializer {
private static final byte[] EMPTY = new byte[0];
/**
* Singleton instance
*/
public static final Serializer<HashedVersion> INSTANCE = new Serializer<HashedVersion>() {
@Override
public HashedVersion fromString(String s) {
return fromString(s, null);
}
@Override
public HashedVersion fromString(String s, HashedVersion defaultValue) {
if (null == s) {
return defaultValue;
}
String[] pair = s.split(":", 2);
long v = Long.parseLong(pair[0]);
byte[] h = EMPTY;
if (pair.length == 2) {
try {
h = CharBase64.decode(pair[1]);
} catch (Base64DecoderException e) {
throw new IllegalArgumentException("Invalid base64 hash: '" + pair[1] + "'");
}
}
return HashedVersion.of(v, h);
}
@Override
public String toString(HashedVersion x) {
return (x != null) ? (x.getVersion() + ":" + CharBase64.encode(x.getHistoryHash())) : null;
}
};
private HashedVersionSerializer() {}
}