Ant example source code file (JavacExternal.java)

This example Ant source code file (JavacExternal.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

buildexception, buildexception, commandline, commandline, defaultcompileradapter, failed, file, io, ioexception, javacexternal, javacexternal, string, using, v, v

The JavacExternal.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.compilers;

import java.io.IOException;
import java.io.File;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.Commandline;
import org.apache.tools.ant.taskdefs.condition.Os;
import org.apache.tools.ant.util.JavaEnvUtils;
import org.apache.tools.ant.util.FileUtils;

/**
 * Performs a compile using javac externally.
 *
 * @since Ant 1.4
 */
public class JavacExternal extends DefaultCompilerAdapter {

    /**
     * Performs a compile using the Javac externally.
     * @return true if the compilation succeeded
     * @throws BuildException on error
     */
    public boolean execute() throws BuildException {
        attributes.log("Using external javac compiler", Project.MSG_VERBOSE);

        Commandline cmd = new Commandline();
        cmd.setExecutable(getJavac().getJavacExecutable());
        if (!assumeJava11() && !assumeJava12()) {
            setupModernJavacCommandlineSwitches(cmd);
        } else {
            setupJavacCommandlineSwitches(cmd, true);
        }
        int firstFileName = assumeJava11() ? -1 : cmd.size();
        logAndAddFilesToCompile(cmd);
        //On VMS platform, we need to create a special java options file
        //containing the arguments and classpath for the javac command.
        //The special file is supported by the "-V" switch on the VMS JVM.
        if (Os.isFamily("openvms")) {
            return execOnVMS(cmd, firstFileName);
        }
        return
                executeExternalCompile(cmd.getCommandline(), firstFileName,
                        true)
                == 0;
    }

    /**
     * helper method to execute our command on VMS.
     * @param cmd
     * @param firstFileName
     * @return
     */
    private boolean execOnVMS(Commandline cmd, int firstFileName) {
        File vmsFile = null;
        try {
            vmsFile = JavaEnvUtils.createVmsJavaOptionFile(cmd.getArguments());
            String[] commandLine = {cmd.getExecutable(),
                                    "-V",
                                    vmsFile.getPath()};
            return 0 == executeExternalCompile(commandLine,
                            firstFileName,
                            true);

        } catch (IOException e) {
            throw new BuildException("Failed to create a temporary file for \"-V\" switch");
        } finally {
            FileUtils.delete(vmsFile);
        }
    }

}