org.elasticsearch.cluster.AbstractNamedDiffable Maven / Gradle / Ivy
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.cluster;
import org.elasticsearch.Version;
import org.elasticsearch.common.io.stream.NamedWriteable;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.core.Nullable;
import java.io.IOException;
/**
* Abstract diffable object with simple diffs implementation that sends the entire object if object has changed or
* nothing is object remained the same. Comparing to AbstractDiffable, this class also works with NamedWriteables
*/
public abstract class AbstractNamedDiffable> implements Diffable, NamedWriteable {
@Override
public Diff diff(T previousState) {
if (this.get().equals(previousState)) {
return new CompleteNamedDiff<>(previousState.getWriteableName(), previousState.getMinimalSupportedVersion());
} else {
return new CompleteNamedDiff<>(get());
}
}
public static > NamedDiff readDiffFrom(Class tClass, String name, StreamInput in)
throws IOException {
return new CompleteNamedDiff<>(tClass, name, in);
}
private static class CompleteNamedDiff> implements NamedDiff {
@Nullable
private final T part;
private final String name;
/**
* A non-null value is only required for write operation, if the diff was just read from the stream the version
* is unnecessary.
*/
@Nullable
private final Version minimalSupportedVersion;
/**
* Creates simple diff with changes
*/
CompleteNamedDiff(T part) {
this.part = part;
this.name = part.getWriteableName();
this.minimalSupportedVersion = part.getMinimalSupportedVersion();
}
/**
* Creates simple diff without changes
*/
CompleteNamedDiff(String name, Version minimalSupportedVersion) {
this.part = null;
this.name = name;
this.minimalSupportedVersion = minimalSupportedVersion;
}
/**
* Read simple diff from the stream
*/
CompleteNamedDiff(Class tClass, String name, StreamInput in) throws IOException {
if (in.readBoolean()) {
this.part = in.readNamedWriteable(tClass, name);
this.minimalSupportedVersion = part.getMinimalSupportedVersion();
} else {
this.part = null;
this.minimalSupportedVersion = null; // We just read this diff, so it's not going to be written
}
this.name = name;
}
@Override
public void writeTo(StreamOutput out) throws IOException {
assert minimalSupportedVersion != null : "shouldn't be called on diff that was de-serialized from the stream";
if (part != null) {
out.writeBoolean(true);
part.writeTo(out);
} else {
out.writeBoolean(false);
}
}
@Override
public T apply(T part) {
if (this.part != null) {
return this.part;
} else {
return part;
}
}
@Override
public String getWriteableName() {
return name;
}
@Override
public Version getMinimalSupportedVersion() {
assert minimalSupportedVersion != null : "shouldn't be called on the diff that was de-serialized from the stream";
return minimalSupportedVersion;
}
}
@SuppressWarnings("unchecked")
public T get() {
return (T) this;
}
}