Substitute.java

/*******************************************************************************
 * Copyright (c) 2004, 2006
 * Thomas Hallgren, Kenneth Olwing, Mitch Sonies
 * Pontus Rydin, Nils Unden, Peer Torngren
 * The code, documentation and other materials contained herein have been
 * licensed under the Eclipse Public License - v 1.0 by the individual
 * copyright holders listed above, as Initial Contributors under such license.
 * The text of such license is available at www.eclipse.org.
 *******************************************************************************/
package org.eclipse.buckminster.ant.taskdefs;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;

/**
 * Performs substitutions on a given value and assings the result to a named
 * property.
 * 
 * @author Thomas Hallgren
 */
public class Substitute extends Task {
	private String property;
	private String pattern;
	private String replacement;
	private String value;
	private boolean quotePattern;

	@Override
	public void execute() throws BuildException {
		if (property == null)
			throw new BuildException("\"property\" must be set");

		if (pattern == null)
			throw new BuildException("\"pattern\" must be set");

		if (replacement == null)
			throw new BuildException("\"replacement\" must be set");

		if (value == null)
			throw new BuildException("\"value\" must be set");

		try {
			String tmp = pattern;
			if (quotePattern)
				tmp = Pattern.quote(tmp);

			Matcher matcher = Pattern.compile(tmp).matcher(value);

			if (matcher.find()) {
				StringBuffer sb = new StringBuffer();
				do {
					matcher.appendReplacement(sb, replacement);
				} while (matcher.find());
				matcher.appendTail(sb);
				tmp = sb.toString();
			} else
				tmp = value;

			this.getProject().setProperty(property, tmp);
		} catch (PatternSyntaxException e) {
			throw new BuildException(e.getMessage());
		}
	}

	/**
	 * Sets the regular expression pattern to use as the match for the
	 * substitution.
	 * 
	 * @param pattern
	 *            A regexp pattern, typcially containing groups that will be
	 *            referenced by the replacement string.
	 */
	public void setPattern(String pattern) {
		this.pattern = pattern;
	}

	/**
	 * Sets the name of the property that will receive the substituted value.
	 * 
	 * @param property
	 *            A property name.
	 */
	public void setProperty(String property) {
		this.property = property;
	}

	/**
	 * Set to <code>true</code> if the pattern should be quoted prior to the
	 * regular expression parsing. The default is <code>false</code>.
	 * 
	 * @param flag
	 */
	public void setQuotePattern(boolean flag) {
		this.quotePattern = flag;
	}

	/**
	 * Sets the replacement string to use in the substitution. <code>$1</code>
	 * denotes the first group of the regular expression, <code>$2</code> the
	 * second, and so on.
	 * 
	 * @param replacement
	 */
	public void setReplacement(String replacement) {
		this.replacement = replacement;
	}

	/**
	 * Sets the source of the substitution.
	 * 
	 * @param value
	 */
	public void setValue(String value) {
		this.value = value;
	}
}