LauncherClasspathHelper.java

/*
 * Copyright 2008 Outerthought bvba and Schaubroeck nv
 *
 * Licensed 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.lilyproject.lilyservertestfwloader;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.regex.Matcher;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class LauncherClasspathHelper {

    private LauncherClasspathHelper() {
    }

    public static ClassLoader getClassLoader(String configResource, File repositoryLocation) {
        return getClassLoader(configResource, repositoryLocation);
    }

    public static ClassLoader getClassLoader(String configResource, File repositoryLocation,
                                             List<URL> additionalClasspathEntries) {
        List<URL> classPath = getClassPath(configResource, repositoryLocation);
        classPath.addAll(additionalClasspathEntries);

        // Set the classpath also in the system property java.class.path
        // When the MapReduce taskjvm.sh scripts are generated,
        // this property is used to set the classpath in the script.
        StringBuilder builder = new StringBuilder();
        String pathSeparator = System.getProperty("path.separator");
        builder.append(System.getProperty("java.class.path"));
        builder.append(pathSeparator);
        for (URL url : classPath) {
            builder.append(url.getFile());
            builder.append(pathSeparator);
        }
        System.setProperty("java.class.path", builder.toString());

        return new URLClassLoader(classPath.toArray(new URL[classPath.size()]), LauncherClasspathHelper.class.getClassLoader());
    }

    public static List<URL> getClassPath(String configResource, File repositoryLocation) {
        Document document;
        InputStream is = LauncherClasspathHelper.class.getClassLoader().getResourceAsStream(configResource);
        if (is == null) {
            throw new RuntimeException("Resource not found: " + configResource);
        } else {
            try {
                document = parse(is);
            } catch (Exception e) {
                throw new RuntimeException("Error parsing classloader configuration at " + configResource, e);
            }
        }

        Element classPathEl = null;
        NodeList children = document.getDocumentElement().getChildNodes();
        for (int i = 0; i < children.getLength(); i++) {
            Node node = children.item(i);
            if (node instanceof Element && node.getLocalName().equals("classpath")) {
                classPathEl = (Element) node;
                break;
            }
        }

        if (classPathEl == null) {
            throw new RuntimeException("Classloader configuration does not contain a classpath element.");
        } else {
            String lilyVersion = getProjectVersion();
            List<URL> artifactURLs = new ArrayList<URL>();
            children = classPathEl.getChildNodes();
            for (int i = 0; i < children.getLength(); i++) {
                Node node = children.item(i);
                if (node instanceof Element && node.getLocalName().equals("artifact")) {
                    Element artifactEl = (Element) node;
                    URL artifactURL = getArtifactURL(artifactEl, repositoryLocation, lilyVersion);
                    if (artifactURL != null) {
                        artifactURLs.add(artifactURL);
                    }
                }
            }
            return artifactURLs;
        }
    }

    public static URL getArtifactURL(Element artifactEl, File repositoryLocation, String lilyVersion) {
        String groupId = artifactEl.getAttribute("groupId");
        String artifactId = artifactEl.getAttribute("artifactId");
        String version = artifactEl.getAttribute("version");
        if (version.equals("")) {
            version = lilyVersion;
        }
        String classifier = artifactEl.getAttribute("classifier");

        String sep = System.getProperty("file.separator");
        String groupPath = groupId.replaceAll("\\.", Matcher.quoteReplacement(sep));
        StringBuilder builder = new StringBuilder();
        builder.append(groupPath);
        builder.append(sep);
        builder.append(artifactId);
        builder.append(sep);
        builder.append(version);
        builder.append(sep);
        builder.append(artifactId);
        builder.append("-");
        builder.append(version);
        if (classifier != null && classifier != "") {
            builder.append("-");
            builder.append(classifier);
        }
        builder.append(".jar");

        File artifactFile = new File(repositoryLocation, builder.toString());

        if (!artifactFile.exists()) {
            throw new RuntimeException("Classpath entry not found at " + artifactFile.getAbsolutePath());
        } else {
            try {
                return artifactFile.toURL();
            } catch (MalformedURLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    public static Document parse(InputStream is) throws ParserConfigurationException, IOException, SAXException {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        return factory.newDocumentBuilder().parse(is);
    }

    private static String getProjectVersion() {
        return readVersion("org.lilyproject", "lily-standalone-launcher");
    }

    public static String readVersion(String groupId, String artifactId) {
        String propPath = "/META-INF/maven/" + groupId + "/" + artifactId + "/pom.properties";
        InputStream is = LauncherClasspathHelper.class.getResourceAsStream(propPath);
        if (is != null) {
            Properties properties = new Properties();
            try {
                properties.load(is);
                String version = properties.getProperty("version");
                if (version != null) {
                    return version;
                }
            } catch (IOException e) {
                // ignore
            }
            try {
                is.close();
            } catch (IOException e) {
                // ignore
            }
        }

        return "undetermined (please report this as bug)";
    }
}