Ant example source code file (AntVersion.java)

This example Ant source code file (AntVersion.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

antversion, buildexception, buildexception, condition, dewey, deweydecimal, deweydecimal, one, only, project, project, string, string, stringbuffer

The AntVersion.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.taskdefs.condition;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.util.DeweyDecimal;

/**
 * An Ant version condition.
 * @since Ant 1.7
 */
public class AntVersion implements Condition {

    private String atLeast = null;
    private String exactly = null;

    /**
     * Evalute the condition.
     * @return true if the condition is true.
     * @throws BuildException if an error occurs.
     */
    public boolean eval() throws BuildException {
        validate();
        DeweyDecimal actual = getVersion();
        if (null != atLeast) {
            return actual.isGreaterThanOrEqual(new DeweyDecimal(atLeast));
        }
        if (null != exactly) {
            return actual.isEqual(new DeweyDecimal(exactly));
        }
        //default
        return false;
    }

    private void validate() throws BuildException {
        if (atLeast != null && exactly != null) {
            throw new BuildException("Only one of atleast or exactly may be set.");
        }
        if (null == atLeast && null == exactly) {
            throw new BuildException("One of atleast or exactly must be set.");
        }
        try {
            if (atLeast != null) {
                new DeweyDecimal(atLeast);
            } else {
                new DeweyDecimal(exactly);
            }
        } catch (NumberFormatException e) {
            throw new BuildException("The argument is not a Dewey Decimal eg 1.1.0");
        }
    }

    private DeweyDecimal getVersion() {
        Project p = new Project();
        p.init();
        char[] versionString = p.getProperty("ant.version").toCharArray();
        StringBuffer sb = new StringBuffer();
        boolean foundFirstDigit = false;
        for (int i = 0; i < versionString.length; i++) {
            if (Character.isDigit(versionString[i])) {
                sb.append(versionString[i]);
                foundFirstDigit = true;
            }
            if (versionString[i] == '.' && foundFirstDigit) {
                sb.append(versionString[i]);
            }
            if (Character.isLetter(versionString[i]) && foundFirstDigit) {
                break;
            }
        }
        return new DeweyDecimal(sb.toString());
    }

    /**
     * Get the atleast attribute.
     * @return the atleast attribute.
     */
    public String getAtLeast() {
        return atLeast;
    }

    /**
     * Set the atleast attribute.
     * This is of the form major.minor.point.
     * For example 1.7.0.
     * @param atLeast the version to check against.
     */
    public void setAtLeast(String atLeast) {
        this.atLeast = atLeast;
    }

    /**
     * Get the exactly attribute.
     * @return the exactly attribute.
     */
    public String getExactly() {
        return exactly;
    }

    /**
     * Set the exactly attribute.
     * This is of the form major.minor.point.
     * For example 1.7.0.
     * @param exactly the version to check against.
     */
    public void setExactly(String exactly) {
        this.exactly = exactly;
    }
}