/*
* 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.apache.flink.core.io;
import org.apache.flink.annotation.Internal;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import java.io.IOException;
import java.util.Arrays;
/**
* This is the abstract base class for {@link IOReadableWritable} which allows to differentiate between serialization
* versions. Concrete subclasses should typically override the {@link #write(DataOutputView)} and
* {@link #read(DataInputView)}, thereby calling super to ensure version checking.
*/
@Internal
public abstract class VersionedIOReadableWritable implements IOReadableWritable, Versioned {
private int readVersion = Integer.MIN_VALUE;
@Override
public void write(DataOutputView out) throws IOException {
out.writeInt(getVersion());
}
@Override
public void read(DataInputView in) throws IOException {
this.readVersion = in.readInt();
resolveVersionRead(readVersion);
}
/**
* Returns the found serialization version. If this instance was not read from serialized bytes
* but simply instantiated, then the current version is returned.
*
* @return the read serialization version, or the current version if the instance was not read from bytes.
*/
public int getReadVersion() {
return (readVersion == Integer.MIN_VALUE) ? getVersion() : readVersion;
}
/**
* Returns the compatible version values.
*
* <p>By default, the base implementation recognizes only the current version (identified by {@link #getVersion()})
* as compatible. This method can be used as a hook and may be overridden to identify more compatible versions.
*
* @return an array of integers representing the compatible version values.
*/
public int[] getCompatibleVersions() {
return new int[] {getVersion()};
}
private void resolveVersionRead(int readVersion) throws VersionMismatchException {
int[] compatibleVersions = getCompatibleVersions();
for (int compatibleVersion : compatibleVersions) {
if (compatibleVersion == readVersion) {
return;
}
}
throw new VersionMismatchException(
"Incompatible version: found " + readVersion + ", compatible versions are " + Arrays.toString(compatibleVersions));
}
}