abstractsearchlistener.java

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/*
*  Copyright (c) 2001 Sun Microsystems, Inc.  All rights
*  reserved.
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*  1. Redistributions of source code must retain the above copyright
*  notice, this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright
*  notice, this list of conditions and the following disclaimer in
*  the documentation and/or other materials provided with the
*  distribution.
*
*  3. The end-user documentation included with the redistribution,
*  if any, must include the following acknowledgment:
*  "This product includes software developed by the
*  Sun Microsystems, Inc. for Project JXTA."
*  Alternately, this acknowledgment may appear in the software itself,
*  if and wherever such third-party acknowledgments normally appear.
*
*  4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA"
*  must not be used to endorse or promote products derived from this
*  software without prior written permission. For written
*  permission, please contact Project JXTA at http://www.jxta.org.
*
*  5. Products derived from this software may not be called "JXTA",
*  nor may "JXTA" appear in their name, without prior written
*  permission of Sun.
*
*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
*  DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
*  ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
*  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
*  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
*  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
*  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
*  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
*  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
*  SUCH DAMAGE.
*  ====================================================================
*
*  This software consists of voluntary contributions made by many
*  individuals on behalf of Project JXTA.  For more
*  information on Project JXTA, please see
*  <http://www.jxta.org/>.
*
*  This license is based on the BSD license adopted by the Apache Foundation.
*
*  $Id: AbstractSearchListener.java,v 1.2 2006/05/17 23:23:01 nano Exp $
*/

package net.jxta.myjxta.search;

import net.jxta.myjxta.util.objectmodel.JxtaNode;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

/**
 *
 * @version $Id: AbstractSearchListener.java,v 1.2 2006/05/17 23:23:01 nano Exp $
 *
 * @author james todd [gonzo at jxta dot org]
 */

public abstract class AbstractSearchListener
    implements SearchListener {

    /** The list of JxtaNode instance discovered by this listener */
    private List<Object> nodes = null;

    /** 
    * Add a new JxtaNode to the registered SearchListener 
    * 
    * @param node the JxtaNode to add 
    */
    public abstract void add(JxtaNode node);

    /**
     * Add a list of JxtaNode instances to the registered SearchListener.
     * This implementation iterates through the list and 
     * calls {@link #add(JxtaNode) add} for each element.
     *
     * @param node the list of JxtaNode instances to add
     */
    public void add(List nodes) {
        for (Iterator i = nodes != null ?
                          nodes.iterator() : Collections.EMPTY_LIST.iterator();
                i.hasNext(); ) {
            add((JxtaNode)i.next());
        }
    }

    /** 
     * Inform the registered listener that the search was
     * terminated. This instance clears its cache, i.e.
     * {@link #nodes nodes}.
     */
    public void terminate() {
        if (this.nodes != null) {
            this.nodes.clear();
        }
    }

    /** 
     * Check whether the indicated object exists in the 
     * cache of the current search. If it does not exist 
     * in the current cache, it is added
     *
     * @param o the object to check for
     * @return true if the object existed in the current cache,
     *         false otherwise
     */
    protected synchronized boolean inCache(Object o) {
        boolean inCache = true;

        if (this.nodes == null) {
            this.nodes = new ArrayList<Object>();
        }

        if (! this.nodes.contains(o)) {
            this.nodes.add(o);

            inCache = false;
        }

        return inCache;
    }
}