src/main/org/apache/tools/ant/NoBannerLogger.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
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 * 5. Products derived from this software may not be called "Apache"
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.ant;

import org.apache.tools.ant.util.StringUtils;

/**
 * Extends DefaultLogger to strip out empty targets.
 *
 * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
 */
public class NoBannerLogger extends DefaultLogger {

    /** 
     * Name of the current target, if it should
     * be displayed on the next message. This is
     * set when a target starts building, and reset
     * to <code>null</code> after the first message for 
     * the target is logged.
     */
    protected String targetName;

    /** Sole constructor. */
    public NoBannerLogger() {
    }

    /**
     * Notes the name of the target so it can be logged
     * if it generates any messages.
     * 
     * @param event A BuildEvent containing target information.
     *              Must not be <code>null</code>.
     */
    public void targetStarted(BuildEvent event) {
        targetName = event.getTarget().getName();
    }

    /** Resets the current target name to <code>null</code>. */
    public void targetFinished(BuildEvent event) {
        targetName = null;
    }

    /**
     * Logs a message for a target if it is of an appropriate
     * priority, also logging the name of the target if this
     * is the first message which needs to be logged for the
     * target.
     * 
     * @param event A BuildEvent containing message information.
     *              Must not be <code>null</code>.
     */
    public void messageLogged(BuildEvent event) {

        if( event.getPriority() > msgOutputLevel ||
                null == event.getMessage() ||
            "".equals( event.getMessage().trim() ) ) {
            return;
        }

        if( null != targetName ) {
            out.println(StringUtils.LINE_SEP + targetName + ":");
            targetName = null;
        }

        super.messageLogged( event );
    }
}