Padding.java

/**
 *        CloudGraph Community Edition (CE) License
 * 
 * This is a community release of CloudGraph, a dual-license suite of
 * Service Data Object (SDO) 2.1 services designed for relational and 
 * big-table style "cloud" databases, such as HBase and others. 
 * This particular copy of the software is released under the 
 * version 2 of the GNU General Public License. CloudGraph was developed by 
 * TerraMeta Software, Inc.
 * 
 * Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
 * 
 * General License information can be found below.
 * 
 * This distribution may include materials developed by third
 * parties. For license and attribution notices for these
 * materials, please refer to the documentation that accompanies
 * this distribution (see the "Licenses for Third-Party Components"
 * appendix) or view the online documentation at 
 * <http://cloudgraph.org/licenses/>. 
 */
package org.cloudgraph.hbase.key;

import java.nio.charset.Charset;
import java.util.Arrays;

import org.plasma.sdo.DataFlavor;

/**
 * Delegate for composite row and column key padding.
 * @author Scott Cinnamond
 * @since 0.5.3
 */
public class Padding {
	private Charset charset;
	private byte zero;
	private byte space;
    @SuppressWarnings("unused")
	private Padding() {}
    public Padding(Charset charset) {
    	this.charset = charset;
    	this.zero = (byte)Character.valueOf('0').charValue();
    	this.space = (byte)Character.valueOf(' ').charValue();
    }

    /**
     * Returns an array front padded with zeros or rear padded
     * with spaces depending on the given data flavor. Returns the given array as is
     * if the given array size is less than or equal to the given max length. 
     * @param value the value
     * @param maxLength the maximum length of the target key field
     * @param dataFlavor the data flavor
     * @return an array front padded with zeros or rear padded
     * with spaces depending on the given data flavor. Returns the given array as is
     * if the given array size is less than or equal to the given max length.
     */
    public final byte[] pad(byte[] value, int maxLength, 
    		DataFlavor dataFlavor) {
    	
    	int len = value.length;
    	int delta = maxLength - len;
    	if (delta <= 0)
    		return value;
    	byte[] result = null;
    	
     	switch (dataFlavor) {
    	case integral:
    	case real: // front pad with zeros
    		result = front(value, maxLength, zero);
    		break;
    	case temporal:
    	case string:
    	case other:
    	default: // end pad with spaces
    		result = back(value, maxLength, space);
    		break;
    	}
     	return result;
    }
    
    public byte[] front(byte[] src, int maxLength, byte pad) {
    	byte[] result = new byte[maxLength];
    	int delta = maxLength - src.length;
		Arrays.fill(result, 0, delta, pad);
		System.arraycopy(src, 
			0, result, delta, src.length);
    	return result;
    }
    
    public byte[] back(byte[] src, int maxLength, byte pad) {
    	byte[] result = new byte[maxLength];
    	int delta = maxLength - src.length;
		System.arraycopy(src, 
        	0, result, 0, src.length);
    	Arrays.fill(result, src.length, 
    		src.length+delta, pad);
    	return result;
    }
    
    /**
     * Returns an array front padded with zeros or rear padded
     * with spaces depending on the given data flavor.
     * @param value the value
     * @param maxLength the maximum length of the target key field
     * @param dataFlavor the data flavor
     * @return an array front padded with zeros or rear padded
     * with spaces depending on the given data flavor.
     */
    public final String pad(String value, int maxLength, 
    		DataFlavor dataFlavor) {
    	int len = value.length();
    	int delta = maxLength - len;
    	if (delta < 0)
    		return value;
		String result = null;
    	
     	switch (dataFlavor) {
    	case integral:
    	case real: // fount pad with zeros
    		result = front(value, maxLength, '0');
    		break;
    	case temporal:
    	case string:
    	case other:
    	default: // end pad with spaces
    		result = back(value, maxLength, ' ');
    		break;
    	}
     	
     	return new String(result);
    }

    public String front(String src, int maxLength, char pad) {
    	char[] result = new char[maxLength];
		char[] srcchars = src.toCharArray();
    	int delta = maxLength - srcchars.length;
    	int offset = delta;
		Arrays.fill(result, 0, delta, pad);
		System.arraycopy(srcchars, 
			0, result, offset, srcchars.length);
    	return new String(result);
    }

    public String back(String src, int maxLength, char pad) {
    	char[] result = new char[maxLength];
		char[] srcchars = src.toCharArray();
    	int delta = maxLength - srcchars.length;
		System.arraycopy(srcchars, 
        	0, result, 0, srcchars.length);
    	Arrays.fill(result, srcchars.length, 
    			srcchars.length+delta, pad);
    	return new String(result);
    }
    

}