extensionvalidator.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * 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.catalina.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;

import javax.naming.Binding;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.DirContext;

import org.apache.catalina.core.StandardContext;
import org.apache.naming.resources.Resource;


/**
 * Ensures that all extension dependies are resolved for a WEB application
 * are met. This class builds a master list of extensions available to an
 * applicaiton and then validates those extensions.
 *
 * See http://java.sun.com/j2se/1.4/docs/guide/extensions/spec.html for
 * a detailed explanation of the extension mechanism in Java.
 *
 * @author Greg Murray
 * @author Justyna Horwat
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 *
 */
public final class ExtensionValidator {

    private static org.apache.juli.logging.Log log=
        org.apache.juli.logging.LogFactory.getLog(ExtensionValidator.class);

    /**
     * The string resources for this package.
     */
    private static StringManager sm =
        StringManager.getManager("org.apache.catalina.util");
    
    private static ArrayList containerAvailableExtensions = null;
    private static ArrayList containerManifestResources = new ArrayList();


    // ----------------------------------------------------- Static Initializer


    /**
     *  This static initializer loads the container level extensions that are
     *  available to all web applications. This method scans all extension 
     *  directories available via the "java.ext.dirs" System property. 
     *
     *  The System Class-Path is also scanned for jar files that may contain 
     *  available extensions.
     */
    static {

        // check for container level optional packages
        String systemClasspath = System.getProperty("java.class.path");

        StringTokenizer strTok = new StringTokenizer(systemClasspath, 
                                                     File.pathSeparator);

        // build a list of jar files in the classpath
        while (strTok.hasMoreTokens()) {
            String classpathItem = strTok.nextToken();
            if (classpathItem.toLowerCase().endsWith(".jar")) {
                File item = new File(classpathItem);
                if (item.exists()) {
                    try {
                        addSystemResource(item);
                    } catch (IOException e) {
                        log.error(sm.getString
                                  ("extensionValidator.failload", item), e);
                    }
                }
            }
        }

        // add specified folders to the list
        addFolderList("java.ext.dirs");
        addFolderList("catalina.ext.dirs");

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Runtime validation of a Web Applicaiton.
     *
     * This method uses JNDI to look up the resources located under a 
     * <code>DirContext</code>. It locates Web Application MANIFEST.MF 
     * file in the /META-INF/ directory of the application and all 
     * MANIFEST.MF files in each JAR file located in the WEB-INF/lib 
     * directory and creates an <code>ArrayList</code> of 
     * <code>ManifestResorce<code> objects. These objects are then passed 
     * to the validateManifestResources method for validation.
     *
     * @param dirContext The JNDI root of the Web Application
     * @param context The context from which the Logger and path to the
     *                application
     *
     * @return true if all required extensions satisfied
     */
    public static synchronized boolean validateApplication(
                                           DirContext dirContext, 
                                           StandardContext context)
                    throws IOException {

        String appName = context.getPath();
        ArrayList appManifestResources = new ArrayList();
        // If the application context is null it does not exist and 
        // therefore is not valid
        if (dirContext == null) return false;
        // Find the Manifest for the Web Applicaiton
        InputStream inputStream = null;
        try {
            NamingEnumeration wne = dirContext.listBindings("/META-INF/");
            Binding binding = (Binding) wne.nextElement();
            if (binding.getName().toUpperCase().equals("MANIFEST.MF")) {
                Resource resource = (Resource)dirContext.lookup
                                    ("/META-INF/" + binding.getName());
                inputStream = resource.streamContent();
                Manifest manifest = new Manifest(inputStream);
                inputStream.close();
                inputStream = null;
                ManifestResource mre = new ManifestResource
                    (sm.getString("extensionValidator.web-application-manifest"),
                    manifest, ManifestResource.WAR);
                appManifestResources.add(mre);
            } 
        } catch (NamingException nex) {
            // Application does not contain a MANIFEST.MF file
        } catch (NoSuchElementException nse) {
            // Application does not contain a MANIFEST.MF file
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (Throwable t) {
                    // Ignore
                }
            }
        }

        // Locate the Manifests for all bundled JARs
        NamingEnumeration ne = null;
        try {
            if (dirContext != null) {
                ne = dirContext.listBindings("WEB-INF/lib/");
            }
            while ((ne != null) && ne.hasMoreElements()) {
                Binding binding = (Binding)ne.nextElement();
                if (!binding.getName().toLowerCase().endsWith(".jar")) {
                    continue;
                }
                Resource resource = (Resource)dirContext.lookup
                                        ("/WEB-INF/lib/" + binding.getName());
                Manifest jmanifest = getManifest(resource.streamContent());
                if (jmanifest != null) {
                    ManifestResource mre = new ManifestResource(
                                                binding.getName(),
                                                jmanifest, 
                                                ManifestResource.APPLICATION);
                    appManifestResources.add(mre);
                }
            }
        } catch (NamingException nex) {
            // Jump out of the check for this application because it 
            // has no resources
        }

        return validateManifestResources(appName, appManifestResources);
    }


    /**
     * Checks to see if the given system JAR file contains a MANIFEST, and adds
     * it to the container's manifest resources.
     *
     * @param jarFile The system JAR whose manifest to add
     */
    public static void addSystemResource(File jarFile) throws IOException {
        Manifest manifest = getManifest(new FileInputStream(jarFile));
        if (manifest != null)  {
            ManifestResource mre
                = new ManifestResource(jarFile.getAbsolutePath(),
                                       manifest,