src/java/org/apache/commons/pool/PoolableObjectFactory.java

/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//pool/src/java/org/apache/commons/pool/PoolableObjectFactory.java,v 1.1 2001/04/14 16:40:53 rwaldhoff Exp $
 * $Revision: 1.1 $
 * $Date: 2001/04/14 16:40:53 $
 *
 * ====================================================================
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 * The Apache Software License, Version 1.1
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package org.apache.commons.pool;

/**
 * A simple interface defining life-cycle methods for
 * <tt>Object</tt>s to be used in an
 * {@link ObjectPool <tt>ObjectPool</tt>}.
 * <p>
 * By contract, when an {@link ObjectPool <tt>ObjectPool</tt>}
 * delegates to a <tt>PoolableObjectFactory</tt>,
 * <ol>
 *  <li>
 *   {@link #makeObject <tt>makeObject</tt>} is called whenever a new <tt>Object</tt>
 *   is needed.
 *  </li>
 *  <li>
 *   {@link #activateObject(java.lang.Object) <tt>activateObject</tt>} is invoked
 *   on every <tt>Object</tt> before it is returned from the
 *   {@link ObjectPool}, and before it is {@link #validateObject validated}.
 *  </li>
 *  <li>
 *   {@link #passivateObject(java.lang.Object) <tt>passivateObject</tt>} is invoked
 *   on every <tt>Object</tt> when it is returned to the
 *   {@link ObjectPool <tt>ObjectPool</tt>}.
 *  </li>
 *  <li>
 *   {@link #destroyObject(java.lang.Object) <tt>destroyObject</tt>} is invoked
 *   on every <tt>Object</tt> when it is being "dropped" from the
 *   {@link ObjectPool <tt>ObjectPool</tt>} (whether due to the response from
 *   {@link #validateObject(java.lang.Object) <tt>validateObject</tt>}, or
 *   for reasons specific to the {@link ObjectPool <tt>ObjectPool</tt>} implementation.)
 *  </li>
 *  <li>
 *   {@link #validateObject(java.lang.Object) <tt>validateObject</tt>} is invoked
 *   in an implementation-specific fashion to determine if an <tt>Object</tt>
 *   is still valid to be returned by the {@link ObjectPool <tt>ObjectPool</tt>}.
 *   It will only be invoked on an {@link #activateObject(java.lang.Object) "activated"}
 *   <tt>Object</tt>.
 *  </li>
 * </ol>
 *
 *
 * @author Rodney Waldhoff
 * @version $Id: PoolableObjectFactory.java,v 1.1 2001/04/14 16:40:53 rwaldhoff Exp $
 *
 * @see ObjectPool
 */
public interface PoolableObjectFactory {
  /**
   * Creates an Object that can be returned by the pool.
   * @return an Object that can be returned by the pool.
   */
  public abstract Object makeObject();

  /**
   * Destroys an Object no longer needed by the pool.
   * @param obj the <tt>Object</tt> to be destroyed
   */
  public abstract void destroyObject(Object obj);

  /**
   * Ensures that the Object is safe to be returned by the pool.
   * Returns <tt>false</tt> if this object should be destroyed.
   * @param obj the <tt>Object</tt> to be validated
   * @return <tt>false</tt> if this <i>obj</i> is not valid and should
   *         be dropped from the pool, <tt>true</tt> otherwise.
   */
  public abstract boolean validateObject(Object obj);

  /**
   * Reinitialize an Object to be returned by the pool.
   * @param obj the <tt>Object</tt> to be activated
   */
  public abstract void activateObject(Object obj);

  /**
   * Uninitialize an Object to be returned to the pool.
   * @param obj the <tt>Object</tt> to be passivated
   */
  public abstract void passivateObject(Object obj);
}