xmllogger.java

Use the links below to download a source distribution of Ant from one of our mirrors. It is good pra

/*
 *  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;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.Writer;
import java.util.Hashtable;
import java.util.Stack;
import java.util.Enumeration;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.apache.tools.ant.util.DOMElementWriter;
import org.apache.tools.ant.util.StringUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Text;

/**
 * Generates a file in the current directory with
 * an XML description of what happened during a build.
 * The default filename is "log.xml", but this can be overridden
 * with the property <code>XmlLogger.file</code>.
 *
 * This implementation assumes in its sanity checking that only one
 * thread runs a particular target/task at a time. This is enforced
 * by the way that parallel builds and antcalls are done - and
 * indeed all but the simplest of tasks could run into problems
 * if executed in parallel.
 *
 * @see Project#addBuildListener(BuildListener)
 */
public class XmlLogger implements BuildLogger {

    private int msgOutputLevel = Project.MSG_DEBUG;
    private PrintStream outStream;

    /** DocumentBuilder to use when creating the document to start with. */
    private static DocumentBuilder builder = getDocumentBuilder();

    /**
     * Returns a default DocumentBuilder instance or throws an
     * ExceptionInInitializerError if it can't be created.
     *
     * @return a default DocumentBuilder instance.
     */
    private static DocumentBuilder getDocumentBuilder() {
        try {
            return DocumentBuilderFactory.newInstance().newDocumentBuilder();
        } catch (Exception exc) {
            throw new ExceptionInInitializerError(exc);
        }
    }

    /** XML element name for a build. */
    private static final String BUILD_TAG = "build";
    /** XML element name for a target. */
    private static final String TARGET_TAG = "target";
    /** XML element name for a task. */
    private static final String TASK_TAG = "task";
    /** XML element name for a message. */
    private static final String MESSAGE_TAG = "message";
    /** XML attribute name for a name. */
    private static final String NAME_ATTR = "name";
    /** XML attribute name for a time. */
    private static final String TIME_ATTR = "time";
    /** XML attribute name for a message priority. */
    private static final String PRIORITY_ATTR = "priority";
    /** XML attribute name for a file location. */
    private static final String LOCATION_ATTR = "location";
    /** XML attribute name for an error description. */
    private static final String ERROR_ATTR = "error";
    /** XML element name for a stack trace. */
    private static final String STACKTRACE_TAG = "stacktrace";

    /** The complete log document for this build. */
    private Document doc = builder.newDocument();
    /** Mapping for when tasks started (Task to TimedElement). */
    private Hashtable tasks = new Hashtable();
    /** Mapping for when targets started (Task to TimedElement). */
    private Hashtable targets = new Hashtable();
    /**
     * Mapping of threads to stacks of elements
     * (Thread to Stack of TimedElement).
     */
    private Hashtable threadStacks = new Hashtable();
    /**
     * When the build started.
     */
    private TimedElement buildElement = null;

    /** Utility class representing the time an element started. */
    private static class TimedElement {
        /**
         * Start time in milliseconds
         * (as returned by <code>System.currentTimeMillis()</code>).
         */
        private long startTime;
        /** Element created at the start time. */
        private Element element;
        public String toString() {
            return element.getTagName() + ":" + element.getAttribute("name");
        }
    }

    /**
     *  Constructs a new BuildListener that logs build events to an XML file.
     */
    public XmlLogger() {
    }

    /**
     * Fired when the build starts, this builds the top-level element for the
     * document and remembers the time of the start of the build.
     *
     * @param event Ignored.
     */
    public void buildStarted(BuildEvent event) {
        buildElement = new TimedElement();
        buildElement.startTime = System.currentTimeMillis();
        buildElement.element = doc.createElement(BUILD_TAG);
    }

    /**
     * Fired when the build finishes, this adds the time taken and any
     * error stacktrace to the build element and writes the document to disk.
     *
     * @param event An event with any relevant extra information.
     *              Will not be <code>null</code>.
     */
    public void buildFinished(BuildEvent event) {
        long totalTime = System.currentTimeMillis() - buildElement.startTime;
        buildElement.element.setAttribute(TIME_ATTR,
                DefaultLogger.formatTime(totalTime));

        if (event.getException() != null) {
            buildElement.element.setAttribute(ERROR_ATTR,
                    event.getException().toString());
            // print the stacktrace in the build file it is always useful...
            // better have too much info than not enough.
            Throwable t = event.getException();
            Text errText = doc.createCDATASection(StringUtils.getStackTrace(t));
            Element stacktrace = doc.createElement(STACKTRACE_TAG);
            stacktrace.appendChild(errText);
            buildElement.element.appendChild(stacktrace);
        }

        String outFilename = event.getProject().getProperty("XmlLogger.file");
        if (outFilename == null) {
            outFilename = "log.xml";
        }
        String xslUri
                = event.getProject().getProperty("ant.XmlLogger.stylesheet.uri");
        if (xslUri == null) {
            xslUri = "log.xsl";
        }
        Writer out = null;
        try {
            // specify output in UTF8 otherwise accented characters will blow
            // up everything
            OutputStream stream = outStream;
            if (stream == null) {
                stream = new FileOutputStream(outFilename);
            }
            out = new OutputStreamWriter(stream, "UTF8");
            out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
            if (xslUri.length() > 0) {
                out.write("<?xml-stylesheet type=\"text/xsl\" href=\""
                        + xslUri + "\"?>\n\n");
            }
            (new DOMElementWriter()).write(buildElement.element, out, 0, "\t");
            out.flush();
        } catch (IOException exc) {
            throw new BuildException("Unable to write log file", exc);
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    // ignore
                }
            }
        }
        buildElement = null;
    }

    /**
     * Returns the stack of timed elements for the current thread.
     * @return the stack of timed elements for the current thread
     */
    private Stack getStack() {
        Stack threadStack = (Stack) threadStacks.get(Thread.currentThread());
        if (threadStack == null) {
            threadStack = new Stack();
            threadStacks.put(Thread.currentThread(), threadStack);
        }
        /* For debugging purposes uncomment:
        org.w3c.dom.Comment s = doc.createComment("stack=" + threadStack);
        buildElement.element.appendChild(s);
         */
        return threadStack;
    }

    /**
     * Fired when a target starts building, this pushes a timed element
     * for the target onto the stack of elements for the current thread,
     * remembering the current time and the name of the target.
     *
     * @param event An event with any relevant extra information.
     *              Will not be <code>null</code>.
     */
    public void targetStarted(BuildEvent event) {
        Target target = event.getTarget();
        TimedElement targetElement = new TimedElement();
        targetElement.startTime = System.currentTimeMillis();
        targetElement.element = doc.createElement(TARGET_TAG);
        targetElement.element.setAttribute(NAME_ATTR, target.getName());
        targets.put(target, targetElement);
        getStack().push(targetElement);
    }

    /**
     * Fired when a target finishes building, this adds the time taken
     * and any error stacktrace to the appropriate target element in the log.