/*
* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package com.sun.jndi.ldap.pool;
/**
* Represents a description of PooledConnection in Connections.
* Contains a PooledConnection, its state (busy, idle, expired), and idle time.
*
* Any access or update to a descriptor's state is synchronized.
*
* @author Rosanna Lee
*/
final class ConnectionDesc {
private final static boolean debug = Pool.debug;
// Package private because used by Pool.showStats()
static final byte BUSY = (byte)0;
static final byte IDLE = (byte)1;
static final byte EXPIRED = (byte)2;
final private PooledConnection conn;
private byte state = IDLE; // initial state
private long idleSince;
private long useCount = 0; // for stats & debugging only
ConnectionDesc(PooledConnection conn) {
this.conn = conn;
}
ConnectionDesc(PooledConnection conn, boolean use) {
this.conn = conn;
if (use) {
state = BUSY;
++useCount;
}
}
/**
* Two desc are equal if their PooledConnections are the same.
* This is useful when searching for a ConnectionDesc using only its
* PooledConnection.
*/
public boolean equals(Object obj) {
return obj != null
&& obj instanceof ConnectionDesc
&& ((ConnectionDesc)obj).conn == conn;
}
/**
* Hashcode is that of PooledConnection to facilitate
* searching for a ConnectionDesc using only its PooledConnection.
*/
public int hashCode() {
return conn.hashCode();
}
/**
* Changes the state of a ConnectionDesc from BUSY to IDLE and
* records the current time so that we will know how long it has been idle.
* @return true if state change occurred.
*/
synchronized boolean release() {
d("release()");
if (state == BUSY) {
state = IDLE;
idleSince = System.currentTimeMillis();
return true; // Connection released, ready for reuse
} else {
return false; // Connection wasn't busy to begin with
}
}
/**
* If ConnectionDesc is IDLE, change its state to BUSY and return
* its connection.
*
* @return ConnectionDesc's PooledConnection if it was idle; null otherwise.
*/
synchronized PooledConnection tryUse() {
d("tryUse()");
if (state == IDLE) {
state = BUSY;
++useCount;
return conn;
}
return null;
}
/**
* If ConnectionDesc is IDLE and has expired, close the corresponding
* PooledConnection.
*
* @param threshold a connection that has been idle before this time
* have expired.
*
* @return true if entry is idle and has expired; false otherwise.
*/
synchronized boolean expire(long threshold) {
if (state == IDLE && idleSince < threshold) {
d("expire(): expired");
state = EXPIRED;
conn.closeConnection(); // Close real connection
return true; // Expiration successful
} else {
d("expire(): not expired");
return false; // Expiration did not occur
}
}
public String toString() {
return conn.toString() + " " +
(state == BUSY ? "busy" : (state == IDLE ? "idle" : "expired"));
}
// Used by Pool.showStats()
int getState() {
return state;
}
// Used by Pool.showStats()
long getUseCount() {
return useCount;
}
private void d(String msg) {
if (debug) {
System.err.println("ConnectionDesc." + msg + " " + toString());
}
}
}