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Java example source code file (BasicManagedEntity.java)

This example source code file (BasicManagedEntity.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java tags/keywords

basicmanagedentity, connectionreleasetrigger, eofsensorwatcher, httpentitywrapper, illegalargumentexception, inputstream, io, ioexception, managedclientconnection, notthreadsafe, outputstream, override

The BasicManagedEntity.java example source code

/*
 * $Revision $
 * ====================================================================
 *
 *  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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.conn;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.http.annotation.NotThreadSafe;

import org.apache.http.HttpEntity;
import org.apache.http.entity.HttpEntityWrapper;

/**
 * An entity that releases a {@link ManagedClientConnection connection}.
 * A {@link ManagedClientConnection} will
 * typically <i>not return a managed entity, but you can replace
 * the unmanaged entity in the response with a managed one.
 *
 * @since 4.0
 */
@NotThreadSafe
public class BasicManagedEntity extends HttpEntityWrapper
    implements ConnectionReleaseTrigger, EofSensorWatcher {

    /** The connection to release. */
    protected ManagedClientConnection managedConn;

    /** Whether to keep the connection alive. */
    protected final boolean attemptReuse;

    /**
     * Creates a new managed entity that can release a connection.
     *
     * @param entity    the entity of which to wrap the content.
     *                  Note that the argument entity can no longer be used
     *                  afterwards, since the content will be taken by this
     *                  managed entity.
     * @param conn      the connection to release
     * @param reuse     whether the connection should be re-used
     */
    public BasicManagedEntity(HttpEntity entity,
                              ManagedClientConnection conn,
                              boolean reuse) {
        super(entity);

        if (conn == null)
            throw new IllegalArgumentException
                ("Connection may not be null.");

        this.managedConn = conn;
        this.attemptReuse = reuse;
    }

    @Override
    public boolean isRepeatable() {
        return false;
    }

    @Override
    public InputStream getContent() throws IOException {
        return new EofSensorInputStream(wrappedEntity.getContent(), this);
    }

    @Override
    public void consumeContent() throws IOException {
        if (managedConn == null)
            return;

        try {
            if (attemptReuse) {
                // this will not trigger a callback from EofSensorInputStream
                wrappedEntity.consumeContent();
                managedConn.markReusable();
            }
        } finally {
            releaseManagedConnection();
        }
    }

    @Override
    public void writeTo(final OutputStream outstream) throws IOException {
        super.writeTo(outstream);
        consumeContent();
    }

    public void releaseConnection() throws IOException {
        this.consumeContent();
    }

    public void abortConnection() throws IOException {

        if (managedConn != null) {
            try {
                managedConn.abortConnection();
            } finally {
                managedConn = null;
            }
        }
    }

    public boolean eofDetected(InputStream wrapped) throws IOException {
        try {
            if (attemptReuse && (managedConn != null)) {
                // there may be some cleanup required, such as
                // reading trailers after the response body:
                wrapped.close();
                managedConn.markReusable();
            }
        } finally {
            releaseManagedConnection();
        }
        return false;
    }

    public boolean streamClosed(InputStream wrapped) throws IOException {
        try {
            if (attemptReuse && (managedConn != null)) {
                // this assumes that closing the stream will
                // consume the remainder of the response body:
                wrapped.close();
                managedConn.markReusable();
            }
        } finally {
            releaseManagedConnection();
        }
        return false;
    }

    public boolean streamAbort(InputStream wrapped) throws IOException {
        if (managedConn != null) {
            managedConn.abortConnection();
        }
        return false;
    }

    /**
     * Releases the connection gracefully.
     * The connection attribute will be nullified.
     * Subsequent invocations are no-ops.
     *
     * @throws IOException      in case of an IO problem.
     *         The connection attribute will be nullified anyway.
     */
    protected void releaseManagedConnection()
        throws IOException {

        if (managedConn != null) {
            try {
                managedConn.releaseConnection();
            } finally {
                managedConn = null;
            }
        }
    }

}

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