headpadfilter.java

java编写的OCR软件

/*
    Jacson
    Copyright (C) 2004 Patrick Carl, pcs_org at users.sf.net
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
 
    This library 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
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 */

package de.spieleck.app.jacson.filter;

import de.spieleck.app.jacson.JacsonConfigException;
import de.spieleck.app.jacson.JacsonException;
import de.spieleck.app.jacson.JacsonRegistry;
import de.spieleck.config.ConfigNode;
import de.spieleck.config.ConfigVerify.Acceptor;



/**
 * <h2>HeadPadFilter</h2>
 * <h3>Description</h3>
 * <p>Filter class which either adds a configurable token as first chunk
 *    or prepends the token to the first chunk. This allows something like
 *    awk's begin.</p>
 * <h3>Parameters</h3>
 * <table border="1" cellpadding="2" cellspacing="0">
 *  <tr>
 *   <td valign="top"><b>Attribute</b></td>
 *   <td valign="top"><b>Description</b></td>
 *   <td align="center" valign="top"><b>Required</b></td>
 *  </tr>
 *  <tr>
 *   <td valign="top">pre</td>
 *   <td valign="top">The token to add at the beginning</td>
 *   <td valign="top" align="center">Yes</td>
 *  </tr>
 *  <tr>
 *   <td valign="top">separatechunk</td>
 *   <td valign="top">Determines if the token is added as separated chunk or
 *       if the token is prepended to the first chunk</td>
 *   <td valign="top" align="center">No, default is false</td>
 *  </tr>
 * </table>
 * @version $Id: HeadPadFilter.java 35 2005-10-03 22:08:55Z pcs $
 * @author pcs
 * @since 0.90
 */

public class HeadPadFilter  extends FilterBase
implements FilterNames, Acceptor{
    
    public static final String PRE_NODE = "pre";
    private String preText;
    
    public static final String SEPARATE_CHUNK_NODE = "separatechunk";
    public static final boolean SEPARATE_CHUNK_DEFAULT = false;
    private boolean ownChunk;
    
    private boolean done = false;
    
    /**
     * string to add is configured via node &quot;pre&quot;
     */
    public void init(ConfigNode snr, JacsonRegistry registry) throws JacsonConfigException {
        preText = snr.getString(PRE_NODE, null);
        if(preText == null)
            throw new JacsonConfigException("HeadPadFilter needs a text to preprend");
        ownChunk = snr.getBoolean(SEPARATE_CHUNK_NODE, SEPARATE_CHUNK_DEFAULT);
    }
    
    /**
     * adds the configured text to the first chunk 
     */
    public void putChunk(String ch) throws JacsonException {
        if(!done){
            if(ownChunk){
                drain.putChunk(preText);
                drain.putChunk(ch);
            } else
                drain.putChunk(preText + ch);
            done= true;
        }
        else
            drain.putChunk(ch);
    }
    
    public boolean accept(ConfigNode node) {
        String name = node.getName();
        return name.equals(PRE_NODE) || name.equals(SEPARATE_CHUNK_NODE);
    }
}