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Ant example source code file (Java.java)

This example Ant source code file (Java.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, cannot, commandlinejava, file, file, io, ioexception, java, jvm, permissions, permissions, please, string, string, util

The Java.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;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.ExitException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.ExitStatusException;
import org.apache.tools.ant.types.Commandline;
import org.apache.tools.ant.types.CommandlineJava;
import org.apache.tools.ant.types.Environment;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.PropertySet;
import org.apache.tools.ant.types.Reference;
import org.apache.tools.ant.types.Assertions;
import org.apache.tools.ant.types.Permissions;
import org.apache.tools.ant.types.RedirectorElement;
import org.apache.tools.ant.taskdefs.condition.Os;
import org.apache.tools.ant.util.KeepAliveInputStream;

/**
 * Launcher for Java applications. Allows use of
 * the same JVM for the called application thus resulting in much
 * faster operation.
 *
 * @since Ant 1.1
 *
 * @ant.task category="java"
 */
public class Java extends Task {

    private CommandlineJava cmdl = new CommandlineJava();
    private Environment env = new Environment();
    private boolean fork = false;
    private boolean newEnvironment = false;
    private File dir = null;
    private boolean failOnError = false;
    private Long timeout = null;

    //include locally for screening purposes
    private String inputString;
    private File input;
    private File output;
    private File error;

    // CheckStyle:VisibilityModifier OFF - bc
    protected Redirector redirector = new Redirector(this);
    protected RedirectorElement redirectorElement;
    // CheckStyle:VisibilityModifier ON

    private String resultProperty;
    private Permissions perm = null;

    private boolean spawn = false;
    private boolean incompatibleWithSpawn = false;

    /**
     * Normal constructor
     */
    public Java() {
    }

    /**
     * create a bound task
     * @param owner owner
     */
    public Java(Task owner) {
        bindToOwner(owner);
    }

    /**
     * Do the execution.
     * @throws BuildException if failOnError is set to true and the application
     * returns a nonzero result code.
     */
    public void execute() throws BuildException {
        File savedDir = dir;
        Permissions savedPermissions = perm;

        int err = -1;
        try {
            err = executeJava();
            if (err != 0) {
                if (failOnError) {
                    throw new ExitStatusException("Java returned: " + err,
                            err,
                            getLocation());
                } else {
                    log("Java Result: " + err, Project.MSG_ERR);
                }
            }
            maybeSetResultPropertyValue(err);
        } finally {
            dir = savedDir;
            perm = savedPermissions;
        }
    }

    /**
     * Do the execution and return a return code.
     *
     * @return the return code from the execute java class if it was
     * executed in a separate VM (fork = "yes") or a security manager was
     * installed that prohibits ExitVM (default).
     *
     * @throws BuildException if required parameters are missing.
     */
    public int executeJava() throws BuildException {
        String classname = getCommandLine().getClassname();
        if (classname == null && getCommandLine().getJar() == null) {
            throw new BuildException("Classname must not be null.");
        }
        if (!fork && getCommandLine().getJar() != null) {
            throw new BuildException("Cannot execute a jar in non-forked mode."
                                     + " Please set fork='true'. ");
        }
        if (spawn && !fork) {
            throw new BuildException("Cannot spawn a java process in non-forked mode."
                                     + " Please set fork='true'. ");
        }
        if (getCommandLine().getClasspath() != null
            && getCommandLine().getJar() != null) {
            log("When using 'jar' attribute classpath-settings are ignored. "
                + "See the manual for more information.", Project.MSG_VERBOSE);
        }
        if (spawn && incompatibleWithSpawn) {
            getProject().log("spawn does not allow attributes related to input, "
            + "output, error, result", Project.MSG_ERR);
            getProject().log("spawn also does not allow timeout", Project.MSG_ERR);
            getProject().log("finally, spawn is not compatible "
                + "with a nested I/O <redirector>", Project.MSG_ERR);
            throw new BuildException("You have used an attribute "
                + "or nested element which is not compatible with spawn");
        }
        if (getCommandLine().getAssertions() != null && !fork) {
            log("Assertion statements are currently ignored in non-forked mode");
        }
        if (fork) {
            if (perm != null) {
                log("Permissions can not be set this way in forked mode.", Project.MSG_WARN);
            }
            log(getCommandLine().describeCommand(), Project.MSG_VERBOSE);
        } else {
            if (getCommandLine().getVmCommand().size() > 1) {
                log("JVM args ignored when same JVM is used.",
                    Project.MSG_WARN);
            }
            if (dir != null) {
                log("Working directory ignored when same JVM is used.",
                    Project.MSG_WARN);
            }
            if (newEnvironment || null != env.getVariables()) {
                log("Changes to environment variables are ignored when same "
                    + "JVM is used.", Project.MSG_WARN);
            }
            if (getCommandLine().getBootclasspath() != null) {
                log("bootclasspath ignored when same JVM is used.",
                    Project.MSG_WARN);
            }
            if (perm == null) {
                perm = new Permissions(true);
                log("running " + this.getCommandLine().getClassname()
                    + " with default permissions (exit forbidden)", Project.MSG_VERBOSE);
            }
            log("Running in same VM " + getCommandLine().describeJavaCommand(),
                Project.MSG_VERBOSE);
        }
        setupRedirector();
        try {
            if (fork) {
                if (!spawn) {
                    return fork(getCommandLine().getCommandline());
                } else {
                    spawn(getCommandLine().getCommandline());
                    return 0;
                }
            } else {
                try {
                    run(getCommandLine());
                    return 0;
                } catch (ExitException ex) {
                    return ex.getStatus();
                }
            }
        } catch (BuildException e) {
            if (e.getLocation() == null && getLocation() != null) {
                e.setLocation(getLocation());
            }
            if (failOnError) {
                throw e;
            } else {
                log(e);
                return 0;
            }
        } catch (ThreadDeath t) {
            throw t; // cf. NB #47191
        } catch (Throwable t) {
            if (failOnError) {
                throw new BuildException(t, getLocation());
            } else {
                log(t);
                return 0;
            }
        }
    }

    /**
     * Set whether or not you want the process to be spawned;
     * default is not spawned.
     * @param spawn if true you do not want Ant to wait for the end of the process.
     * @since Ant 1.6
     */
    public void setSpawn(boolean spawn) {
        this.spawn = spawn;
    }

    /**
     * Set the classpath to be used when running the Java class.
     *
     * @param s an Ant Path object containing the classpath.
     */
    public void setClasspath(Path s) {
        createClasspath().append(s);
    }

    /**
     * Add a path to the classpath.
     *
     * @return created classpath.
     */
    public Path createClasspath() {
        return getCommandLine().createClasspath(getProject()).createPath();
    }

    /**
     * Add a path to the bootclasspath.
     * @since Ant 1.6
     *
     * @return created bootclasspath.
     */
    public Path createBootclasspath() {
        return getCommandLine().createBootclasspath(getProject()).createPath();
    }

    /**
     * Set the permissions for the application run inside the same JVM.
     * @since Ant 1.6
     * @return Permissions.
     */
    public Permissions createPermissions() {
        perm = (perm == null) ? new Permissions() : perm;
        return perm;
    }

    /**
     * Set the classpath to use by reference.
     *
     * @param r a reference to an existing classpath.
     */
    public void setClasspathRef(Reference r) {
        createClasspath().setRefid(r);
    }

    /**
     * Set the location of the JAR file to execute.
     *
     * @param jarfile the jarfile to execute.
     *
     * @throws BuildException if there is also a main class specified.
     */
    public void setJar(File jarfile) throws BuildException {
        if (getCommandLine().getClassname() != null) {
            throw new BuildException("Cannot use 'jar' and 'classname' "
                                     + "attributes in same command.");
        }
        getCommandLine().setJar(jarfile.getAbsolutePath());
    }

    /**
     * Set the Java class to execute.
     *
     * @param s the name of the main class.
     *
     * @throws BuildException if the jar attribute has been set.
     */
    public void setClassname(String s) throws BuildException {
        if (getCommandLine().getJar() != null) {
            throw new BuildException("Cannot use 'jar' and 'classname' "
                                     + "attributes in same command");
        }
        getCommandLine().setClassname(s);
    }

    /**
     * Deprecated: use nested arg instead.
     * Set the command line arguments for the class.
     *
     * @param s arguments.
     *
     * @ant.attribute ignore="true"
     */
    public void setArgs(String s) {
        log("The args attribute is deprecated. "
            + "Please use nested arg elements.", Project.MSG_WARN);
        getCommandLine().createArgument().setLine(s);
    }

    /**
     * If set, system properties will be copied to the cloned VM--as
     * well as the bootclasspath unless you have explicitly specified
     * a bootclaspath.
     *
     * <p>Doesn't have any effect unless fork is true.

* @param cloneVm if true copy system properties. * @since Ant 1.7 */ public void setCloneVm(boolean cloneVm) { getCommandLine().setCloneVm(cloneVm); } /** * Add a command-line argument. * * @return created argument. */ public Commandline.Argument createArg() { return getCommandLine().createArgument(); } /** * Set the name of the property in which the return code of the * command should be stored. Only of interest if failonerror=false. * * @param resultProperty name of property. * * @since Ant 1.6 */ public void setResultProperty(String resultProperty) { this.resultProperty = resultProperty; incompatibleWithSpawn = true; } /** * Helper method to set result property to the * passed in value if appropriate. * * @param result the exit code */ protected void maybeSetResultPropertyValue(int result) { String res = Integer.toString(result); if (resultProperty != null) { getProject().setNewProperty(resultProperty, res); } } /** * If true, execute in a new VM. * * @param s do you want to run Java in a new VM. */ public void setFork(boolean s) { this.fork = s; } /** * Set the command line arguments for the JVM. * * @param s jvmargs. */ public void setJvmargs(String s) { log("The jvmargs attribute is deprecated. " + "Please use nested jvmarg elements.", Project.MSG_WARN); getCommandLine().createVmArgument().setLine(s); } /** * Adds a JVM argument. * * @return JVM argument created. */ public Commandline.Argument createJvmarg() { return getCommandLine().createVmArgument(); } /** * Set the command used to start the VM (only if forking). * * @param s command to start the VM. */ public void setJvm(String s) { getCommandLine().setVm(s); } /** * Add a system property. * * @param sysp system property. */ public void addSysproperty(Environment.Variable sysp) { getCommandLine().addSysproperty(sysp); } /** * Add a set of properties as system properties. * * @param sysp set of properties to add. * * @since Ant 1.6 */ public void addSyspropertyset(PropertySet sysp) { getCommandLine().addSyspropertyset(sysp); } /** * If true, then fail if the command exits with a * returncode other than zero. * * @param fail if true fail the build when the command exits with a * nonzero returncode. */ public void setFailonerror(boolean fail) { failOnError = fail; incompatibleWithSpawn |= fail; } /** * Set the working directory of the process. * * @param d working directory. * */ public void setDir(File d) { this.dir = d; } /** * Set the File to which the output of the process is redirected. * * @param out the output File. */ public void setOutput(File out) { this.output = out; incompatibleWithSpawn = true; } /** * Set the input to use for the task. * * @param input name of the input file. */ public void setInput(File input) { if (inputString != null) { throw new BuildException("The \"input\" and \"inputstring\" " + "attributes cannot both be specified"); } this.input = input; incompatibleWithSpawn = true; } /** * Set the string to use as input. * * @param inputString the string which is used as the input source. */ public void setInputString(String inputString) { if (input != null) { throw new BuildException("The \"input\" and \"inputstring\" " + "attributes cannot both be specified"); } this.inputString = inputString; incompatibleWithSpawn = true; } /** * Set whether error output of exec is logged. This is only useful * when output is being redirected and error output is desired in the * Ant log. * * @param logError get in the ant log the messages coming from stderr * in the case that fork = true. */ public void setLogError(boolean logError) { redirector.setLogError(logError); incompatibleWithSpawn |= logError; } /** * Set the File to which the error stream of the process is redirected. * * @param error file getting the error stream. * * @since Ant 1.6 */ public void setError(File error) { this.error = error; incompatibleWithSpawn = true; } /** * Set the property name whose value should be set to the output of * the process. * * @param outputProp property name. * */ public void setOutputproperty(String outputProp) { redirector.setOutputProperty(outputProp); incompatibleWithSpawn = true; } /** * Set the property name whose value should be set to the error of * the process. * * @param errorProperty property name. * * @since Ant 1.6 */ public void setErrorProperty(String errorProperty) { redirector.setErrorProperty(errorProperty); incompatibleWithSpawn = true; } /** * Corresponds to -mx or -Xmx depending on VM version. * * @param max max memory parameter. */ public void setMaxmemory(String max) { getCommandLine().setMaxmemory(max); } /** * Set the JVM version. * @param value JVM version. */ public void setJVMVersion(String value) { getCommandLine().setVmversion(value); } /** * Add an environment variable. * * <p>Will be ignored if we are not forking a new VM. * * @param var new environment variable. * * @since Ant 1.5 */ public void addEnv(Environment.Variable var) { env.addVariable(var); } /** * If true, use a completely new environment. * * <p>Will be ignored if we are not forking a new VM. * * @param newenv if true, use a completely new environment. * * @since Ant 1.5 */ public void setNewenvironment(boolean newenv) { newEnvironment = newenv; } /** * If true, append output to existing file. * * @param append if true, append output to existing file. * * @since Ant 1.5 */ public void setAppend(boolean append) { redirector.setAppend(append); incompatibleWithSpawn = true; } /** * Set the timeout in milliseconds after which the process will be killed. * * @param value timeout in milliseconds. * * @since Ant 1.5 */ public void setTimeout(Long value) { timeout = value; incompatibleWithSpawn |= timeout != null; } /** * Add assertions to enable in this program (if fork=true). * @param asserts assertion set. * @since Ant 1.6 */ public void addAssertions(Assertions asserts) { if (getCommandLine().getAssertions() != null) { throw new BuildException("Only one assertion declaration is allowed"); } getCommandLine().setAssertions(asserts); } /** * Add a <code>RedirectorElement to this task. * @param redirectorElement <code>RedirectorElement. */ public void addConfiguredRedirector(RedirectorElement redirectorElement) { if (this.redirectorElement != null) { throw new BuildException("cannot have > 1 nested redirectors"); } this.redirectorElement = redirectorElement; incompatibleWithSpawn = true; } /** * Pass output sent to System.out to specified output file. * * @param output a string of output on its way to the handlers. * * @since Ant 1.5 */ protected void handleOutput(String output) { if (redirector.getOutputStream() != null) { redirector.handleOutput(output); } else { super.handleOutput(output); } } /** * Handle an input request by this task. * * @param buffer the buffer into which data is to be read. * @param offset the offset into the buffer at which data is stored. * @param length the amount of data to read. * * @return the number of bytes read. * * @exception IOException if the data cannot be read. * @since Ant 1.6 */ public int handleInput(byte[] buffer, int offset, int length) throws IOException { // Should work whether or not redirector.inputStream == null: return redirector.handleInput(buffer, offset, length); } /** * Pass output sent to System.out to specified output file. * * @param output string of output on its way to its handlers. * * @since Ant 1.5.2 */ protected void handleFlush(String output) { if (redirector.getOutputStream() != null) { redirector.handleFlush(output); } else { super.handleFlush(output); } } /** * Handle output sent to System.err. * * @param output string of stderr. * * @since Ant 1.5 */ protected void handleErrorOutput(String output) { if (redirector.getErrorStream() != null) { redirector.handleErrorOutput(output); } else { super.handleErrorOutput(output); } } /** * Handle output sent to System.err and flush the stream. * * @param output string of stderr. * * @since Ant 1.5.2 */ protected void handleErrorFlush(String output) { if (redirector.getErrorStream() != null) { redirector.handleErrorFlush(output); } else { super.handleErrorOutput(output); } } /** * Set up properties on the redirector that we needed to store locally. */ protected void setupRedirector() { redirector.setInput(input); redirector.setInputString(inputString); redirector.setOutput(output); redirector.setError(error); if (redirectorElement != null) { redirectorElement.configure(redirector); } if (!spawn && input == null && inputString == null) { // #24918: send standard input to the process by default. redirector.setInputStream( new KeepAliveInputStream(getProject().getDefaultInputStream())); } } /** * Executes the given classname with the given arguments as it * were a command line application. * @param command CommandlineJava. */ private void run(CommandlineJava command) throws BuildException { try { ExecuteJava exe = new ExecuteJava(); exe.setJavaCommand(command.getJavaCommand()); exe.setClasspath(command.getClasspath()); exe.setSystemProperties(command.getSystemProperties()); exe.setPermissions(perm); exe.setTimeout(timeout); redirector.createStreams(); exe.execute(getProject()); redirector.complete(); if (exe.killedProcess()) { throw new BuildException("Timeout: killed the sub-process"); } } catch (IOException e) { throw new BuildException(e); } } /** * Executes the given classname with the given arguments in a separate VM. * @param command String[] of command-line arguments. */ private int fork(String[] command) throws BuildException { Execute exe = new Execute(redirector.createHandler(), createWatchdog()); setupExecutable(exe, command); try { int rc = exe.execute(); redirector.complete(); if (exe.killedProcess()) { throw new BuildException("Timeout: killed the sub-process"); } return rc; } catch (IOException e) { throw new BuildException(e, getLocation()); } } /** * Executes the given classname with the given arguments in a separate VM. * @param command String[] of command-line arguments. */ private void spawn(String[] command) throws BuildException { Execute exe = new Execute(); setupExecutable(exe, command); try { exe.spawn(); } catch (IOException e) { throw new BuildException(e, getLocation()); } } /** * Do all configuration for an executable that * is common across the {@link #fork(String[])} and * {@link #spawn(String[])} methods. * @param exe executable. * @param command command to execute. */ private void setupExecutable(Execute exe, String[] command) { exe.setAntRun(getProject()); setupWorkingDir(exe); setupEnvironment(exe); setupCommandLine(exe, command); } /** * Set up our environment variables. * @param exe executable. */ private void setupEnvironment(Execute exe) { String[] environment = env.getVariables(); if (environment != null) { for (int i = 0; i < environment.length; i++) { log("Setting environment variable: " + environment[i], Project.MSG_VERBOSE); } } exe.setNewenvironment(newEnvironment); exe.setEnvironment(environment); } /** * Set the working dir of the new process. * @param exe executable. * @throws BuildException if the dir doesn't exist. */ private void setupWorkingDir(Execute exe) { if (dir == null) { dir = getProject().getBaseDir(); } else if (!dir.exists() || !dir.isDirectory()) { throw new BuildException(dir.getAbsolutePath() + " is not a valid directory", getLocation()); } exe.setWorkingDirectory(dir); } /** * Set the command line for the exe. * On VMS, hands off to {@link #setupCommandLineForVMS(Execute, String[])}. * @param exe executable. * @param command command to execute. */ private void setupCommandLine(Execute exe, String[] command) { //On VMS platform, we need to create a special java options file //containing the arguments and classpath for the java command. //The special file is supported by the "-V" switch on the VMS JVM. if (Os.isFamily("openvms")) { setupCommandLineForVMS(exe, command); } else { exe.setCommandline(command); } } /** * On VMS platform, we need to create a special java options file * containing the arguments and classpath for the java command. * The special file is supported by the "-V" switch on the VMS JVM. * * @param exe executable. * @param command command to execute. */ private void setupCommandLineForVMS(Execute exe, String[] command) { ExecuteJava.setupCommandLineForVMS(exe, command); } /** * Executes the given classname with the given arguments as if it * were a command line application. * * @param classname the name of the class to run. * @param args arguments for the class. * @throws BuildException in case of IOException in the execution. */ protected void run(String classname, Vector args) throws BuildException { CommandlineJava cmdj = new CommandlineJava(); cmdj.setClassname(classname); for (int i = 0; i < args.size(); i++) { cmdj.createArgument().setValue((String) args.elementAt(i)); } run(cmdj); } /** * Clear out the arguments to this java task. */ public void clearArgs() { getCommandLine().clearJavaArgs(); } /** * Create the Watchdog to kill a runaway process. * * @return new watchdog. * * @throws BuildException under unknown circumstances. * * @since Ant 1.5 */ protected ExecuteWatchdog createWatchdog() throws BuildException { if (timeout == null) { return null; } return new ExecuteWatchdog(timeout.longValue()); } /** * Log the specified Throwable. * @param t the Throwable to log. * @since 1.6.2 */ private void log(Throwable t) { StringWriter sw = new StringWriter(); PrintWriter w = new PrintWriter(sw); t.printStackTrace(w); w.close(); log(sw.toString(), Project.MSG_ERR); } /** * Accessor to the command line. * * @return the current command line. * @since 1.6.3 */ public CommandlineJava getCommandLine() { return cmdl; } /** * Get the system properties of the command line. * * @return the current properties of this java invocation. * @since 1.6.3 */ public CommandlineJava.SysProperties getSysProperties() { return getCommandLine().getSystemProperties(); } }

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