wordfilter.java

Java写的ERP系统

/*
 * Copyright (c) 1999 The Java Apache Project.  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. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Java Apache
 *    Project. <http://java.apache.org/>"
 *
 * 4. The names "Java Apache Element Construction Set", "Java Apache ECS" and
 *    "Java Apache Project" must not be used to endorse or promote products
 *    derived from this software without prior written permission.
 *
 * 5. Products derived from this software may not be called
 *    "Java Apache Element Construction Set" nor "Java Apache ECS" appear
 *    in their names without prior written permission of the
 *    Java Apache Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Java Apache
 *    Project. <http://java.apache.org/>"
 *
 * THIS SOFTWARE IS PROVIDED BY THE JAVA APACHE PROJECT "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 JAVA APACHE PROJECT 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 the Java Apache Project. For more information
 * on the Java Apache Project please see <http://java.apache.org/>.
 *
 */
package org.apache.ecs.filter;

import org.apache.ecs.Filter;
import java.text.StringCharacterIterator;
import java.text.CharacterIterator;
import java.util.StringTokenizer;

/**
    This filter uses StringTokenizer to create "words" and allow
    you to replace on those "words". A word is defined as anything
    between two spaces. This filter should be relatively fast and
    shows how easy it is to implement your own filters.

<pre><code>
    Filter filter = new WordFilter();
    filter.addAttribute("there","where");
    filter.addAttribute("it","is");
    filter.addAttribute("goes","it");
    P p = new P();
    p.setFilter(filter);
    p.addElement("there it goes");
    System.out.println(p.toString());
</code></pre>

    Produces: &lt;p&gt;where is it

    @version $Id: WordFilter.java,v 1.2 2001/11/06 03:43:33 jjanke Exp $
    @author <a href="mailto:[e-mail]">Stephan Nagy</a>
    @author <a href="mailto:[e-mail]">Jon S. Stevens</a>
*/
public class WordFilter extends java.util.Hashtable implements Filter
{
    public WordFilter()
    {
		super(4);
    }

    /** Returns the name of the filter */
    public String getInfo()
    {
        return "WordFilter";
    }

    /**
        this method actually performs the filtering.
    */
    public String process(String to_process)
    {
        if ( to_process == null || to_process.length() == 0 )
            return "";

        String tmp = "";
        // the true at the end is the key to making it work
        StringTokenizer st = new StringTokenizer(to_process, " ", true);
        StringBuffer newValue = new StringBuffer(to_process.length() + 50);
        while ( st.hasMoreTokens() )
        {
            tmp = st.nextToken();
            if (hasAttribute(tmp))
                newValue.append((String)get(tmp));
            else
                newValue.append(tmp);
        }
        return newValue.toString();
    }

    /**
        Put a filter somewhere we can get to it.
    */
    public Filter addAttribute(String attribute,Object entity)
    {
        put(attribute,entity);
        return(this);
    }

    /**
        Get rid of a current filter.
    */
    public Filter removeAttribute(String attribute)
    {
        try
        {
            remove(attribute);
        }
        catch(NullPointerException exc)
        { // don't really care if this throws a null pointer exception
        }
        return(this);
    }

    /**
        Does the filter filter this?
    */
    public boolean hasAttribute(String attribute)
    {
        return(containsKey(attribute));
    }
}