org.apache.jxtadoop.ipc.ConnectionHeader.java Source code

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Here is the source code for org.apache.jxtadoop.ipc.ConnectionHeader.java

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/**
 * 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.jxtadoop.ipc;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.jxtadoop.io.Text;

import org.apache.jxtadoop.io.Writable;
import org.apache.jxtadoop.security.UnixUserGroupInformation;
import org.apache.jxtadoop.security.UserGroupInformation;

/**
 * The IPC connection header sent by the client to the server
 * on connection establishment.
 */
public class ConnectionHeader implements Writable {
    public static final Log LOG = LogFactory.getLog(ConnectionHeader.class);

    private String protocol;
    private UserGroupInformation ugi = new UnixUserGroupInformation();

    public ConnectionHeader() {
    }

    /**
     * Create a new {@link ConnectionHeader} with the given <code>protocol</code>
     * and {@link UserGroupInformation}. 
     * @param protocol protocol used for communication between the IPC client
     *                 and the server
     * @param ugi {@link UserGroupInformation} of the client communicating with
     *            the server
     */
    public ConnectionHeader(String protocol, UserGroupInformation ugi) {
        this.protocol = protocol;
        this.ugi = ugi;
    }

    public void readFields(DataInput in) throws IOException {
        protocol = Text.readString(in);
        if (protocol.isEmpty()) {
            protocol = null;
        }

        boolean ugiPresent = in.readBoolean();
        if (ugiPresent) {
            ugi.readFields(in);
        } else {
            ugi = null;
        }
    }

    public void write(DataOutput out) throws IOException {
        Text.writeString(out, (protocol == null) ? "" : protocol);
        if (ugi != null) {
            out.writeBoolean(true);
            ugi.write(out);
        } else {
            out.writeBoolean(false);
        }
    }

    public String getProtocol() {
        return protocol;
    }

    public UserGroupInformation getUgi() {
        return ugi;
    }

    public String toString() {
        return protocol + "-" + ugi;
    }
}