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/*-*- mode: Java; tab-width:8 -*-*/

package io.soluble.pjb.bridge.http;

/*
 * Copyright (C) 2003-2007 Jost Boekemeier
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import io.soluble.pjb.bridge.Util;

/**
 * A connection pool. Example:

* * ConnectionPool pool = new ConnectionPool("127.0.0.1", 8080, 20, 5000, new IOFactory());
* ConnectionPool.Connection conn = pool.openConnection();
* InputStream in = conn.getInputStream();
* OutputStream out = conn.getOutputStream();
* ...
* in.close();
* out.close();
* ...
* pool.destroy();
*
*

Instead of using delegation (decorator pattern), it is possible to pass a factory * which may create custom In- and OutputStreams. Example:

* * new ConnectionPool(..., new IOFactory() {
*   public InputStream getInputStream() {
*     return new DefaultInputStream() {
*       ...
*     }
*   }
* }
*
*

* * @author jostb */ public class FCGIConnectionPool { private int limit; private long timeout; private int connections = 0; private List freeList = new LinkedList(); private List connectionList = new LinkedList(); private FCGIIOFactory factory; private int maxRequests; private FCGIConnectionFactory channelName; /** * Represents the connection kept by the pool. * * @author jostb */ public final class Connection { protected int ostate, state; // bit0: input closed, bit1: output closed protected FCGIConnectionFactory channelName; protected FCGIConnection channel; private FCGIConnectionOutputStream outputStream; private FCGIConnectionInputStream inputStream; private boolean isClosed; private FCGIIOFactory factory; private int maxRequests; private int counter; protected void reset() { this.state = this.ostate = 0; } protected void init() { inputStream = null; outputStream = null; counter = maxRequests; reset(); } protected Connection reopen() throws FCGIConnectException { if (isClosed) this.channel = factory.connect(channelName); this.isClosed = false; return this; } protected Connection(FCGIConnectionFactory channelName, int maxRequests, FCGIIOFactory factory) { this.channelName = channelName; this.factory = factory; this.isClosed = true; this.maxRequests = maxRequests; init(); } /** * Set the closed/abort flag for this connection */ public void setIsClosed() { isClosed = true; } protected void close() throws FCGIConnectException { // PHP child terminated: mark as closed, so that reopen() can allocate // a new connection for the new PHP child if (maxRequests > 0 && --counter == 0) isClosed = true; if (isClosed) { destroy(); init(); } closeConnection(this); } private void destroy() { try { channel.close(); } catch (IOException e) {/*ignore*/} } /** * Returns the OutputStream associated with this connection. * * @return The output stream. * @throws FCGIConnectionException */ public OutputStream getOutputStream() throws FCGIConnectionException { if (outputStream != null) return outputStream; FCGIConnectionOutputStream outputStream = (FCGIConnectionOutputStream) factory.createOutputStream(); outputStream.setConnection(this); ostate |= 2; return outputStream; } /** * Returns the InputStream associated with this connection. * * @return The input stream. * @throws FCGIConnectionException */ public InputStream getInputStream() throws FCGIConnectionException { if (inputStream != null) return inputStream; FCGIConnectionInputStream inputStream = (FCGIConnectionInputStream) factory.createInputStream(); inputStream.setConnection(this); ostate |= 1; return inputStream; } } /** * Create a new connection pool. * * @param channelName The channel name * @param limit The max. number of physical connections * @param maxRequests * @param factory A factory for creating In- and OutputStreams. * @throws FCGIConnectException * @see FCGIIOFactory */ private FCGIConnectionPool(FCGIConnectionFactory channelName, int limit, int maxRequests, FCGIIOFactory factory) throws FCGIConnectException { if (Util.logLevel > 3) Util.logDebug("Creating new connection pool for: " + channelName); this.channelName = channelName; this.limit = limit; this.factory = factory; this.maxRequests = maxRequests; this.timeout = -1; channelName.test(); } /** * Create a new connection pool. * * @param channelName The channel name * @param limit The max. number of physical connections * @param maxRequests * @param factory A factory for creating In- and OutputStreams. * @param timeout The pool timeout in milliseconds. * @throws FCGIConnectException * @see FCGIIOFactory */ public FCGIConnectionPool(FCGIConnectionFactory channelName, int limit, int maxRequests, FCGIIOFactory factory, long timeout) throws FCGIConnectException { this(channelName, limit, maxRequests, factory); this.timeout = timeout; } /* helper for openConnection() */ private Connection createNewConnection() { Connection connection = new Connection(channelName, maxRequests, factory); connectionList.add(connection); connections++; return connection; } /** * Opens a connection to the back end. * * @return The connection * @throws InterruptedException * @throws FCGIConnectException */ public synchronized Connection openConnection() throws InterruptedException, FCGIConnectException { Connection connection; if (freeList.isEmpty() && connections < limit) { connection = createNewConnection(); } else { while (freeList.isEmpty()) { if (timeout > 0) { long t1 = System.currentTimeMillis(); wait(timeout); long t2 = System.currentTimeMillis(); long t = t2 - t1; if (t >= timeout) throw new FCGIConnectException(new IOException("pool timeout " + timeout + " exceeded: " + t)); } else { wait(); } } connection = (Connection) freeList.remove(0); connection.reset(); } return connection.reopen(); } private synchronized void closeConnection(Connection connection) { freeList.add(connection); notify(); } /** * Destroy the connection pool. *

* It releases all physical connections. */ public synchronized void destroy() { for (Iterator ii = connectionList.iterator(); ii.hasNext(); ) { Connection connection = (Connection) ii.next(); connection.destroy(); } if (channelName != null) channelName.destroy(); } }





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