Header.java

/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.transport;

import org.opensearch.Version;
import org.opensearch.common.annotation.PublicApi;
import org.opensearch.common.collect.Tuple;
import org.opensearch.common.util.concurrent.ThreadContext;
import org.opensearch.core.common.io.stream.StreamInput;

import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

/**
 * Transport Header
 *
 * @opensearch.api
 */
@PublicApi(since = "1.0.0")
public class Header {

    private static final String RESPONSE_NAME = "NO_ACTION_NAME_FOR_RESPONSES";

    private final int networkMessageSize;
    private final Version version;
    private final long requestId;
    private final byte status;
    // These are directly set by tests
    String actionName;
    Tuple<Map<String, String>, Map<String, Set<String>>> headers;
    Set<String> features;

    Header(int networkMessageSize, long requestId, byte status, Version version) {
        this.networkMessageSize = networkMessageSize;
        this.version = version;
        this.requestId = requestId;
        this.status = status;
    }

    public int getNetworkMessageSize() {
        return networkMessageSize;
    }

    Version getVersion() {
        return version;
    }

    long getRequestId() {
        return requestId;
    }

    byte getStatus() {
        return status;
    }

    boolean isRequest() {
        return TransportStatus.isRequest(status);
    }

    boolean isResponse() {
        return TransportStatus.isRequest(status) == false;
    }

    boolean isError() {
        return TransportStatus.isError(status);
    }

    boolean isHandshake() {
        return TransportStatus.isHandshake(status);
    }

    boolean isCompressed() {
        return TransportStatus.isCompress(status);
    }

    public String getActionName() {
        return actionName;
    }

    boolean needsToReadVariableHeader() {
        return headers == null;
    }

    public Set<String> getFeatures() {
        return features;
    }

    Tuple<Map<String, String>, Map<String, Set<String>>> getHeaders() {
        return headers;
    }

    void finishParsingHeader(StreamInput input) throws IOException {
        this.headers = ThreadContext.readHeadersFromStream(input);

        if (isRequest()) {
            final String[] featuresFound = input.readStringArray();
            if (featuresFound.length == 0) {
                features = Collections.emptySet();
            } else {
                features = Collections.unmodifiableSet(new TreeSet<>(Arrays.asList(featuresFound)));
            }
            this.actionName = input.readString();
        } else {
            this.actionName = RESPONSE_NAME;
        }
    }

    @Override
    public String toString() {
        return "Header{"
            + networkMessageSize
            + "}{"
            + version
            + "}{"
            + requestId
            + "}{"
            + isRequest()
            + "}{"
            + isError()
            + "}{"
            + isHandshake()
            + "}{"
            + isCompressed()
            + "}{"
            + actionName
            + "}";
    }
}