com.ibm.as400.access.CADSPool Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jt400 Show documentation
The Open Source version of the IBM Toolbox for Java
The newest version!
///////////////////////////////////////////////////////////////////////////////
//                                                                             
// JTOpen (IBM Toolbox for Java - OSS version)                                 
//                                                                             
// Filename: CADSPool.java
//                                                                             
// The source code contained herein is licensed under the IBM Public License   
// Version 1.0, which has been approved by the Open Source Initiative.         
// Copyright (C) 1997-2001 International Business Machines Corporation and     
// others. All rights reserved.                                                
//                                                                             
///////////////////////////////////////////////////////////////////////////////

package com.ibm.as400.access;

import java.util.LinkedList;

// This class is used to pool ClientAccessDataStream objects.
final class CADSPool
{
  private static final String copyright = "Copyright (C) 1997-2001 International Business Machines Corporation and others.";

  private ClientAccessDataStream[] streams_ = new ClientAccessDataStream[4];
  // Performance optimization for linkedList of returned data streams.  
  private LinkedList linkedList_ = null;  
  private final Object streamsLock_ = new Object(); //@P1A
  private int searchStart_ = 0; 
  
  public CADSPool() {
    try {
        linkedList_ = new LinkedList(); 
    } catch (Throwable e) {
      // Ignore any errors if the linked list cannot be created
      // this will fall back to the older implemenation
      
    }
  }
  final ClientAccessDataStream getUnusedStream()
  {
    synchronized(streamsLock_) //@P1C
    {
      ClientAccessDataStream returnStream = null; 
      // Use the linked list if available
      if (linkedList_ != null) {
        
        while (linkedList_.size() > 0) {
          returnStream = (ClientAccessDataStream) linkedList_.removeFirst();
          if (returnStream.canUse()) {
            return returnStream; 
          }
          
        }
        
      }
      
      
      int max = streams_.length;
      for (int i= searchStart_; i