Ant example source code file (RegularExpression.java)

This example Ant source code file (RegularExpression.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

data_type_name, datatype, factory, regexp, regexp, regexpfactory, regexpfactory, regularexpression, regularexpression, string, string

The RegularExpression.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.tools.ant.types;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.util.regexp.Regexp;
import org.apache.tools.ant.util.regexp.RegexpFactory;

/***
 * A regular expression datatype.  Keeps an instance of the
 * compiled expression for speed purposes.  This compiled
 * expression is lazily evaluated (it is compiled the first
 * time it is needed).  The syntax is the dependent on which
 * regular expression type you are using.  The system property
 * "ant.regexp.regexpimpl" will be the classname of the implementation
 * that will be used.
 *
 * <pre>
 * For jdk  <= 1.3, there are two available implementations:
 *   org.apache.tools.ant.util.regexp.JakartaOroRegexp (the default)
 *        Based on the jakarta-oro package
 *
 *   org.apache.tools.ant.util.regexp.JakartaRegexpRegexp
 *        Based on the jakarta-regexp package
 *
 * For jdk >= 1.4 an additional implementation is available:
 *   org.apache.tools.ant.util.regexp.Jdk14RegexpRegexp
 *        Based on the jdk 1.4 built in regular expression package.
 * </pre>
 *
 * <pre>
 *   <regexp [ [id="id"] pattern="expression" | refid="id" ]
 *   />
 * </pre>
 *
 * @see org.apache.oro.text.regex.Perl5Compiler
 * @see org.apache.regexp.RE
 * @see java.util.regex.Pattern
 *
 * @see org.apache.tools.ant.util.regexp.Regexp
 *
 * @ant.datatype name="regexp"
 */
public class RegularExpression extends DataType {
    /** Name of this data type */
    public static final String DATA_TYPE_NAME = "regexp";
    private boolean alreadyInit = false;

    // The regular expression factory
    private static final RegexpFactory FACTORY = new RegexpFactory();

    private Regexp regexp = null;
    // temporary variable
    private String myPattern;
    private boolean setPatternPending = false;

    /**
     * default constructor
     */
    public RegularExpression() {
    }

    private void init(Project p) {
        if (!alreadyInit) {
            this.regexp = FACTORY.newRegexp(p);
            alreadyInit = true;
        }
    }
    private void setPattern() {
        if (setPatternPending) {
            regexp.setPattern(myPattern);
            setPatternPending = false;
        }
    }
    /**
     * sets the regular expression pattern
     * @param pattern regular expression pattern
     */
    public void setPattern(String pattern) {
        if (regexp == null) {
            myPattern = pattern;
            setPatternPending = true;
        } else {
            regexp.setPattern(pattern);
        }
    }

    /***
     * Gets the pattern string for this RegularExpression in the
     * given project.
     * @param p project
     * @return pattern
     */
    public String getPattern(Project p) {
        init(p);
        if (isReference()) {
            return getRef(p).getPattern(p);
        }
        setPattern();
        return regexp.getPattern();
    }

    /**
     * provides a reference to the Regexp contained in this
     * @param p  project
     * @return   Regexp instance associated with this RegularExpression instance
     */
    public Regexp getRegexp(Project p) {
        init(p);
        if (isReference()) {
            return getRef(p).getRegexp(p);
        }
        setPattern();
        return this.regexp;
    }

    /***
     * Get the RegularExpression this reference refers to in
     * the given project.  Check for circular references too
     * @param p project
     * @return resolved RegularExpression instance
     */
    public RegularExpression getRef(Project p) {
        return (RegularExpression) getCheckedRef(p);
    }
}