http://nexus.sonatype.org/oss-repository-hosting.html/ST4: StringTemplate is a java template engine for generating source code, web pages, emails, or any other formatted text output. StringTemplate is particularly good at multi-targeted code generators, multiple site skins, and internationalization/localization. It evolved over years of effort developing jGuru.com. StringTemplate also powers the ANTLR 3 and 4 code generator. Its distinguishing characteristic is that unlike other engines, it strictly enforces model-view separation. Strict separation makes websites and code generators more flexible and maintainable; it also provides an excellent defense against malicious template authors. 
/*
 * [The "BSD license"]
 *  Copyright (c) 2011 Terence Parr
 *  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 name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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.
 */
package org.stringtemplate.v4;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Formatter;
import java.util.Locale;


Works with Byte, Short, Integer, Long, and BigInteger as well as Float, Double, and BigDecimal. You pass in a format string suitable for Formatter.format. 
 For example, %10d emits a number as a decimal int padding to 10 char. This can even do long to Date conversions using the format string.


/** Works with {@link Byte}, {@link Short}, {@link Integer}, {@link Long}, and {@link BigInteger} as well as
 *  {@link Float}, {@link Double}, and {@link BigDecimal}.  You pass in a format string suitable
 *  for {@link Formatter#format}.
 *  <p>
 *  For example, {@code %10d} emits a number as a decimal int padding to 10 char.
 *  This can even do {@code long} to {@code Date} conversions using the format string.</p>
 */
public class NumberRenderer implements AttributeRenderer {
	@Override
    public String toString(Object o, String formatString, Locale locale) {
        // o will be instanceof Number
        if ( formatString==null ) return o.toString();
        Formatter f = new Formatter(locale);
        try {
            f.format(formatString, o);
            return f.toString();
        }
        finally {
            f.close();
        }
    }
}