content: /*
   *  This file is part of AndroidIDE.
   *
   *  AndroidIDE is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
   *  (at your option) any later version.
   *
   *  AndroidIDE 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 for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * reserved comment block
   * DO NOT REMOVE OR ALTER!
   */
  /*
   * Copyright 1999-2004 The Apache Software Foundation.
   *
   * Licensed 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.
   */
  /*
   * $Id: ObjectPool.java,v 1.2.4.1 2005/09/15 08:15:50 suresh_emailid Exp $
   */
  package jaxp.sun.org.apache.xml.internal.utils;
  
  import java.util.ArrayList;
  
  import jaxp.sun.org.apache.xml.internal.res.XMLErrorResources;
  import jaxp.sun.org.apache.xml.internal.res.XMLMessages;
  import jaxp.sun.org.apache.xalan.internal.utils.ObjectFactory;
  
  
  /**
   * Pool of object of a given type to pick from to help memory usage
   * @xsl.usage internal
   */
  public class ObjectPool implements java.io.Serializable
  {
      static final long serialVersionUID = -8519013691660936643L;
  
    /** Type of objects in this pool.
     *  @serial          */
    private final Class objectType;
  
    /** Stack of given objects this points to.
     *  @serial          */
    private final ArrayList freeStack;
  
    /**
     * Constructor ObjectPool
     *
     * @param type Type of objects for this pool
     */
    public ObjectPool(Class type)
    {
      objectType = type;
      freeStack = new ArrayList();
    }
  
    /**
     * Constructor ObjectPool
     *
     * @param className Fully qualified name of the type of objects for this pool.
     */
    public ObjectPool(String className)
    {
      try
      {
        objectType = ObjectFactory.findProviderClass(className, true);
      }
      catch(ClassNotFoundException cnfe)
      {
        throw new WrappedRuntimeException(cnfe);
      }
      freeStack = new ArrayList();
    }
  
  
    /**
     * Constructor ObjectPool
     *
     *
     * @param type Type of objects for this pool
     * @param size Size of vector to allocate
     */
    public ObjectPool(Class type, int size)
    {
      objectType = type;
      freeStack = new ArrayList(size);
    }
  
    /**
     * Constructor ObjectPool
     *
     */
    public ObjectPool()
    {
      objectType = null;
      freeStack = new ArrayList();
    }
  
    /**
     * Get an instance of the given object in this pool if available
     *
     *
     * @return an instance of the given object if available or null
     */
    public synchronized Object getInstanceIfFree()
    {
  
      // Check if the pool is empty.
      if (!freeStack.isEmpty())
      {
  
        // Remove object from end of free pool.
        Object result = freeStack.remove(freeStack.size() - 1);
        return result;
      }
  
      return null;
    }
  
    /**
     * Get an instance of the given object in this pool
     *
     *
     * @return An instance of the given object
     */
    public synchronized Object getInstance()
    {
  
      // Check if the pool is empty.
      if (freeStack.isEmpty())
      {
  
        // Create a new object if so.
        try
        {
          return objectType.newInstance();
        }
        catch (InstantiationException ex){}
        catch (IllegalAccessException ex){}
  
        // Throw unchecked exception for error in pool configuration.
        throw new RuntimeException(XMLMessages.createXMLMessage(XMLErrorResources.ER_EXCEPTION_CREATING_POOL, null)); //"exception creating new instance for pool");
      }
      else
      {
  
        // Remove object from end of free pool.
        Object result = freeStack.remove(freeStack.size() - 1);
        return result;
      }
    }
  
    /**
     * Add an instance of the given object to the pool
     *
     *
     * @param obj Object to add.
     */
    public synchronized void freeInstance(Object obj)
    {
  
      // Make sure the object is of the correct type.
      // Remove safety.  -sb
      // if (objectType.isInstance(obj))
      // {
      freeStack.add(obj);
      // }
      // else
      // {
      //  throw new IllegalArgumentException("argument type invalid for pool");
      // }
    }
  }
  