org.elasticsearch.common.io.stream.VersionedNamedWriteable Maven / Gradle / Ivy

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Elasticsearch subproject :server

There is a newer version: 8.13.4

/*
 * 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.common.io.stream;

import org.elasticsearch.Version;
import org.elasticsearch.common.collect.ImmutableOpenMap;

import java.io.IOException;

/**
 * A {@link NamedWriteable} that has a minimum version associated with it.
 */
public interface VersionedNamedWriteable extends NamedWriteable {

    /**
     * Returns the name of the writeable object
     */
    String getWriteableName();

    /**
     * The minimal version of the recipient this object can be sent to
     */
    Version getMinimalSupportedVersion();

    /**
     * Tests whether or not the custom should be serialized. The criteria is the output stream must be at least the minimum supported
     * version of the custom. That is, we only serialize customs to clients than can understand the custom based on the version of the
     * client.
     *
     * @param out    the output stream
     * @param custom the custom to serialize
     * @param     the type of the custom
     * @return true if the custom should be serialized and false otherwise
     */
    static  boolean shouldSerialize(final StreamOutput out, final T custom) {
        return out.getVersion().onOrAfter(custom.getMinimalSupportedVersion());
    }

    /**
     * Writes all those values in the given map to {@code out} that pass the version check in {@link #shouldSerialize} as a list.
     *
     * @param out     stream to write to
     * @param customs map of customs
     * @param      type of customs in map
     */
    static  void writeVersionedWritables(StreamOutput out, ImmutableOpenMap customs)
        throws IOException {
        // filter out custom states not supported by the other node
        int numberOfCustoms = 0;
        for (final T value : customs.values()) {
            if (shouldSerialize(out, value)) {
                numberOfCustoms++;
            }
        }
        out.writeVInt(numberOfCustoms);
        for (final T value : customs.values()) {
            if (shouldSerialize(out, value)) {
                out.writeNamedWriteable(value);
            }
        }
    }
}