/*
* Copyright (C) 2005 Alfresco, Inc.
*
* Licensed under the Mozilla Public License version 1.1
* with a permitted attribution clause. You may obtain a
* copy of the License at
*
* http://www.alfresco.org/legal/license.txt
*
* 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.alfresco.filesys.server.oncrpc;
import java.util.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Rpc Packet Pool Class
*
* <p>Contains a pool of small and large RpcPacket objects for use by multi-threaded RPC servers.
*
* @author GKSpencer
*/
public class RpcPacketPool {
// Debug logging
private static final Log logger = LogFactory.getLog(RpcPacketPool.class);
// Constants
//
// Default small/large packet sizes
public static final int DefaultSmallSize = 512;
public static final int DefaultLargeSize = 32768;
public static final int DefaultSmallLimit = -1; // no allocation limit
public static final int DefaultLargeLimit = -1; // " " "
// Small/large packet lists
private Vector m_smallPackets;
private Vector m_largePackets;
// Small packet size and maximum allowed packets
private int m_smallPktSize;
private int m_smallPktLimit;
// Large packet size and maximum allowed packets
private int m_largePktSize;
private int m_largePktLimit;
// Count of allocated small/large packets
private int m_smallPktCount;
private int m_largePktCount;
/**
* Default constructor
*/
public RpcPacketPool()
{
// Create the small/large packet lists
m_smallPackets = new Vector();
m_largePackets = new Vector();
// Set the packet sizes/limits
m_smallPktSize = DefaultSmallSize;
m_smallPktLimit = DefaultSmallLimit;
m_largePktSize = DefaultLargeSize;
m_largePktLimit = DefaultLargeLimit;
}
/**
* Class constructor
*
* @param smallSize int
* @param smallLimit int
* @param largeSize int
* @param largeLimit int
*/
public RpcPacketPool(int smallSize, int smallLimit, int largeSize, int largeLimit)
{
// Create the small/large packet lists
m_smallPackets = new Vector();
m_largePackets = new Vector();
// Save the packet sizes/limits
m_smallPktSize = smallSize;
m_smallPktLimit = smallLimit;
m_largePktSize = largeSize;
m_largePktLimit = largeLimit;
}
/**
* Class constructor
*
* @param largeSize int
* @param largeLimit int
*/
public RpcPacketPool(int largeSize, int largeLimit)
{
// Create the small/large packet lists
m_smallPackets = new Vector();
m_largePackets = new Vector();
// Save the packet sizes/limits
m_smallPktSize = DefaultSmallSize;
m_smallPktLimit = largeLimit;
m_largePktSize = largeSize;
m_largePktLimit = largeLimit;
}
/**
* Return the small packet size
*
* @return int
*/
public final int getSmallPacketSize()
{
return m_smallPktSize;
}
/**
* Return the count of allocated small packets
*
* @return int
*/
public final int getSmallPacketCount()
{
return m_smallPktCount;
}
/**
* Return the small packet allocation limit
*
* @return int
*/
public final int getSmallPacketAllocationLimit()
{
return m_smallPktLimit;
}
/**
* Return the count of available large packets
*
* @return int
*/
public final int availableLargePackets()
{
return m_largePackets.size();
}
/**
* Return the large packet size
*
* @return int
*/
public final int getLargePacketSize()
{
return m_largePktSize;
}
/**
* Return the count of allocated large packets
*
* @return int
*/
public final int getLargePacketCount()
{
return m_largePktCount;
}
/**
* Return the large packet allocation limit
*
* @return int
*/
public final int getLargePacketAllocationLimit()
{
return m_largePktLimit;
}
/**
* Return the count of available small packets
*
* @return int
*/
public final int availableSmallPackets()
{
return m_smallPackets.size();
}
/**
* Allocate a packet from the packet pool
*
* @param reqSize int
* @return RpcPacket
*/
public final RpcPacket allocatePacket(int reqSize)
{
// Check if the packet should come from the small or large packet list
RpcPacket pkt = null;
if (reqSize <= m_smallPktSize)
{
// Allocate a packet from the small packet list
pkt = allocateSmallPacket();
// DEBUG
if (logger.isDebugEnabled())
logger.debug("RpcPacketPool Allocated (small) " + pkt.getBuffer() + ", len=" + pkt.getBuffer().length
+ ", list=" + m_smallPackets.size() + "/" + m_smallPktLimit);
} else
{
// Allocate a packet from the large packet list
pkt = allocateLargePacket();
// DEBUG
if (logger.isDebugEnabled())
logger.debug("RpcPacketPool Allocated (large) " + pkt.getBuffer() + ", len=" + pkt.getBuffer().length
+ ", list=" + m_largePackets.size() + "/" + m_largePktLimit);
}
// Return the allocated packet
return pkt;
}
/**
* Release an RPC packet back to the pool
*
* @param pkt RpcPacket
*/
public final void releasePacket(RpcPacket pkt)
{
// Check if the packet should be released to the small or large list
if (pkt.getBuffer().length >= m_largePktSize)
{
// Release the packet to the large packet list
synchronized (m_largePackets)
{
// Add the packet back to the free list
m_largePackets.addElement(pkt);
// Signal any waiting threads that there are packets available
m_largePackets.notify();
// DEBUG
if (logger.isDebugEnabled())
logger.debug("RpcPacketPool Released (large) " + pkt.getBuffer() + ", len="
+ pkt.getBuffer().length + ", list=" + m_largePackets.size());
}
} else
{
// Release the packet to the small packet list
synchronized (m_smallPackets)
{
// Add the packet back to the free list
m_smallPackets.addElement(pkt);
// Signal any waiting threads that there are packets available
m_smallPackets.notify();
// DEBUG
if (logger.isDebugEnabled())
logger.debug("RpcPacketPool Released (small) " + pkt.getBuffer() + ", len="
+ pkt.getBuffer().length);
}
}
}
/**
* Allocate, or create, a small RPC packet
*
* @return RpcPacket
*/
private final RpcPacket allocateSmallPacket()
{
RpcPacket pkt = null;
synchronized (m_smallPackets)
{
// Check if there is a packet available from the small packet list
if (m_smallPackets.size() > 0)
{
// Remove a packet from the head of the free list
pkt = (RpcPacket) m_smallPackets.elementAt(0);
m_smallPackets.removeElementAt(0);
} else if (m_smallPktLimit == -1 || m_smallPktCount < m_smallPktLimit)
{
// Allocate a new packet
pkt = new RpcPacket(m_smallPktSize, this);
m_smallPktCount++;
} else
{
// Wait for a packet to be released to the small packet list
try
{
// Wait for a packet
m_smallPackets.wait();
// Try to get the packet from the small packet list again
if (m_smallPackets.size() > 0)
{
// Remove a packet from the head of the free list
pkt = (RpcPacket) m_smallPackets.elementAt(0);
m_smallPackets.removeElementAt(0);
}
} catch (InterruptedException ex)
{
}
}
}
// Return the allocated packet
return pkt;
}
/**
* Allocate, or create, a large RPC packet
*
* @return RpcPacket
*/
private final RpcPacket allocateLargePacket()
{
RpcPacket pkt = null;
synchronized (m_largePackets)
{
// Check if there is a packet available from the large packet list
if (m_largePackets.size() > 0)
{
// Remove a packet from the head of the free list
pkt = (RpcPacket) m_largePackets.elementAt(0);
m_largePackets.removeElementAt(0);
} else if (m_largePktLimit == -1 || m_largePktCount < m_largePktLimit)
{
// Allocate a new packet
pkt = new RpcPacket(m_largePktSize, this);
m_largePktCount++;
} else
{
// Wait for a packet to be released to the large packet list
try
{
// Wait for a packet
m_largePackets.wait();
// Try to get the packet from the large packet list again
if (m_largePackets.size() > 0)
{
// Remove a packet from the head of the free list
pkt = (RpcPacket) m_largePackets.elementAt(0);
m_largePackets.removeElementAt(0);
}
} catch (InterruptedException ex)
{
}
}
}
// Return the allocated packet
return pkt;
}
}