leftpadder.java

java pos,你可以直接编译运行,

/*
 * Copyright (c) 2000 jPOS.org. 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 jPOS project (http://www.jpos.org/)". Alternately, this
 * acknowledgment may appear in the software itself, if and wherever such
 * third-party acknowledgments normally appear.
 *  4. The names "jPOS" and "jPOS.org" must not be used to endorse or promote
 * products derived from this software without prior written permission. For
 * written permission, please contact [e-mail].
 *  5. Products derived from this software may not be called "jPOS", nor may
 * "jPOS" appear in their name, without prior written permission of the jPOS
 * project.
 * 
 * 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 JPOS
 * 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 jPOS Project. For more information please see
 * <http://www.jpos.org/> .
 */

package org.jpos.iso;

import org.jpos.iso.ISOException;

/**
 * Implements the Padder interface for padding strings and byte arrays on the
 * left.
 * 
 * @author joconnor
 * @version $Revision: 1.2 $ $Date: 2003/11/05 09:00:22 $
 */
public class LeftPadder implements Padder
{
    /**
	 * A padder for padding zeros on the left. This is very common in numeric
	 * fields.
	 */
    public static final LeftPadder ZERO_PADDER = new LeftPadder('0');

    private char pad;

    /**
	 * Creates a Left Padder with a specific pad character.
	 * 
	 * @param pad
	 *            The padding character. For binary padders, the pad character
	 *            is truncated to lower order byte.
	 */
    public LeftPadder(char pad)
    {
        this.pad = pad;
    }

    /**
	 * @see org.jpos.iso.Padder#pad(java.lang.String, int, char)
	 */
    public String pad(String data, int maxLength) throws ISOException
    {
        StringBuffer padded = new StringBuffer(maxLength);
        int len = data.length();
        if (len > maxLength)
        {
            throw new ISOException("Data is too long. Max = " + maxLength);
        } else
        {
            for (int i = maxLength - len; i > 0; i--)
            {
                padded.append(pad);
            }
            padded.append(data);
        }
        return padded.toString();
    }

    /**
	 * (non-Javadoc)
	 * 
	 * @see org.jpos.iso.Padder#unpad(java.lang.String, char)
	 */
    public String unpad(String paddedData)
    {
        int i = 0;
        int len = paddedData.length();
        while (i < len)
        {
            if (paddedData.charAt(i) != pad)
            {
                return paddedData.substring(i);
            }
            i++;
        }
        return "";
    }
}