package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.types.Commandline;

/**
 * An <code>AssertionArgument</code> represents a command line argument to
 * the <code>java</code> command for enabling and disabling runtime assertions.
 *
 * An <code>AssertionArgument</code> is instantiated for each
 * &lt;enableassertions&gt; and &lt;disableassertions&gt; nested
 * inside of a &lt;java&gt; task.
 * <br><br>
 * <b>Example:</b>
   <pre>
     &lt;java classname="test.Main"
           classpathref="project.classpath"&gt;
       &lt;enableassertions package="org.apache.tools.ant"/&gt;
       &lt;disableassertions class="org.apache.tools.ant.BuildException"/&gt;
     &lt;/java&gt;
   </pre>
 *
 * This would enable assertions for the <code>org.apache.tools.ant</code>
 * package and all of its sub-packages and would disable assertions for
 * <code>org.apache.tools.ant.BuildException</code>.  The command line would
 * look like...<br><br>
 *
 * <code>java -ea:org.apache.tools.ant...
 * -da:org.apache.tools.ant.BuildException test.Main</code>
 * <br><br>
 * Refer to the J2SE tools documentation for more details on enabling and disabling
 * assertions.
 * @author Jeff Brown <a href="mailto:brown_j@ociweb.com">brown_j@ociweb.com</a>
 * @see org.apache.tools.ant.taskdefs.Java
 */
public class AssertionArgument {

    /**
     * The argument wrapped inside of this <code>AssertionArgument</code>
     */
    private Commandline.Argument argument;

    /**
     * The argument prefix for enabling assertions
     */
    public static final String ENABLE_ASSERTS_ARG  = "-ea";

    /**
     * The argument prefix for disabling assertions
     */
    public static final String DISABLE_ASSERTS_ARG = "-da";

    /**
     * The error message for the case when both a class attribute and a
     * package attribute are applied to a single
     * <code>AssertionArgument</code>
     */
    public static final String DUPLICATE_SPEC_ERR_MSG =
        "Cannot use 'package' and 'class' attributes " +
        "in the same enableassert element.";

    /**
     * The prefix to the argument that will be passed on the command line
     */
    private final String assertionArgPrefix;

    /**
     * @param arg The <code>Commandline.Argument</code> being wrapped
     * @param enableAssertions <code>true</code> if this
     * <code>AssertionArgument</code> should be enabling assertions,
     * <code>false</code> if this <code>AssertionArgument</code> should be
     * disabling assertions
     */
    public AssertionArgument(Commandline.Argument arg,
                             boolean enableAssertions) {
        argument = arg;
        assertionArgPrefix = (enableAssertions ?
                              ENABLE_ASSERTS_ARG :
                              DISABLE_ASSERTS_ARG);
        argument.setLine(assertionArgPrefix);
    }

    /**
     * @param p The package to be specified on the command line
     */
    public void setPackage(String p) {
        // assertionArgPrefix will be either ENABLE_ASSERTS_ARG or
        // DISABLE_ASSERTS_ARG.  If the first part of argument is
        // NOT one of these two strings, then the class attribute
        // must have already been specified.  This is not legal.
        // Each AssertionArgument must have either
        //  1.) No specification applied (-de or -ea)
        //  2.) A class specification applied (-de:org.apache.test.Main)
        //  3.) A package specification applied (-de:org.apache.tools...)
        if(!(assertionArgPrefix.equals(argument.getParts()[0]))) {
            throw new BuildException(DUPLICATE_SPEC_ERR_MSG);
        }

        // set the command line argument
        argument.setLine(assertionArgPrefix + ":" + p + "...");
    }

    /**
     * @param c The class to be specified on the command line
     */
    public void setClass(String c) {
        // assertionArgPrefix will be either ENABLE_ASSERTS_ARG or
        // DISABLE_ASSERTS_ARG.  If the first part of argument is
        // NOT one of these two strings, then the package attribute
        // must have already been specified.  This is not legal.
        // Each AssertionArgument must have either
        //  1.) No specification applied (-de or -ea)
        //  2.) A class specification applied (-de:org.apache.test.Main)
        //  3.) A package specification applied (-de:org.apache.tools...)
        if(!(assertionArgPrefix.equals(argument.getParts()[0]))) {
            throw new BuildException(DUPLICATE_SPEC_ERR_MSG);
        }

        // set the command line argument
        argument.setLine(assertionArgPrefix + ":" + c);
    }
}