jspruntimecontext.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.jasper.compiler;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FilePermission;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.CodeSource;
import java.security.PermissionCollection;
import java.security.Policy;
import java.security.cert.Certificate;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.ServletContext;
import javax.servlet.jsp.JspFactory;

import org.apache.jasper.Constants;
import org.apache.jasper.JspCompilationContext;
import org.apache.jasper.Options;
import org.apache.jasper.runtime.JspFactoryImpl;
import org.apache.jasper.security.SecurityClassLoad;
import org.apache.jasper.servlet.JspServletWrapper;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

/**
 * Class for tracking JSP compile time file dependencies when the
 * &060;%@include file="..."%&062; directive is used.
 *
 * A background thread periodically checks the files a JSP page
 * is dependent upon.  If a dpendent file changes the JSP page
 * which included it is recompiled.
 *
 * Only used if a web application context is a directory.
 *
 * @author Glenn L. Nielsen
 * @version $Revision: 505593 $
 */
public final class JspRuntimeContext {

    // Logger
    private Log log = LogFactory.getLog(JspRuntimeContext.class);

    /*
     * Counts how many times the webapp's JSPs have been reloaded.
     */
    private int jspReloadCount;

    /**
     * Preload classes required at runtime by a JSP servlet so that
     * we don't get a defineClassInPackage security exception.
     */
    static {
        JspFactoryImpl factory = new JspFactoryImpl();
        SecurityClassLoad.securityClassLoad(factory.getClass().getClassLoader());
        if( System.getSecurityManager() != null ) {
            String basePackage = "org.apache.jasper.";
            try {
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "runtime.JspFactoryImpl$PrivilegedGetPageContext");
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "runtime.JspFactoryImpl$PrivilegedReleasePageContext");
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "runtime.JspRuntimeLibrary");
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "runtime.JspRuntimeLibrary$PrivilegedIntrospectHelper");
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "runtime.ServletResponseWrapperInclude");
                factory.getClass().getClassLoader().loadClass( basePackage +
                                                               "servlet.JspServletWrapper");
            } catch (ClassNotFoundException ex) {
                throw new IllegalStateException(ex);
            }
        }

        JspFactory.setDefaultFactory(factory);
    }

    // ----------------------------------------------------------- Constructors

    /**
     * Create a JspRuntimeContext for a web application context.
     *
     * Loads in any previously generated dependencies from file.
     *
     * @param context ServletContext for web application
     */
    public JspRuntimeContext(ServletContext context, Options options) {

        this.context = context;
        this.options = options;

        // Get the parent class loader
        parentClassLoader =
            (URLClassLoader) Thread.currentThread().getContextClassLoader();
        if (parentClassLoader == null) {
            parentClassLoader =
                (URLClassLoader)this.getClass().getClassLoader();
        }

	if (log.isDebugEnabled()) {
	    if (parentClassLoader != null) {
		log.debug(Localizer.getMessage("jsp.message.parent_class_loader_is",
					       parentClassLoader.toString()));
	    } else {
		log.debug(Localizer.getMessage("jsp.message.parent_class_loader_is",
					       "<none>"));
	    }
        }

        initClassPath();

	if (context instanceof org.apache.jasper.servlet.JspCServletContext) {
	    return;
	}

        if (Constants.IS_SECURITY_ENABLED) {
            initSecurity();
        }

        // If this web application context is running from a
        // directory, start the background compilation thread
        String appBase = context.getRealPath("/");         
        if (!options.getDevelopment()
                && appBase != null
                && options.getCheckInterval() > 0) {
            lastCheck = System.currentTimeMillis();
        }                                            
    }

    // ----------------------------------------------------- Instance Variables

    /**
     * This web applications ServletContext
     */
    private ServletContext context;
    private Options options;
    private URLClassLoader parentClassLoader;
    private PermissionCollection permissionCollection;
    private CodeSource codeSource;                    
    private String classpath;
    private long lastCheck = -1L;

    /**
     * Maps JSP pages to their JspServletWrapper's
     */
    private Map<String, JspServletWrapper> jsps = new ConcurrentHashMap<String, JspServletWrapper>();
 

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

    /**
     * Add a new JspServletWrapper.
     *
     * @param jspUri JSP URI
     * @param jsw Servlet wrapper for JSP
     */
    public void addWrapper(String jspUri, JspServletWrapper jsw) {
        jsps.put(jspUri, jsw);
    }

    /**
     * Get an already existing JspServletWrapper.
     *
     * @param jspUri JSP URI
     * @return JspServletWrapper for JSP
     */
    public JspServletWrapper getWrapper(String jspUri) {
        return jsps.get(jspUri);
    }

    /**
     * Remove a  JspServletWrapper.
     *
     * @param jspUri JSP URI of JspServletWrapper to remove
     */
    public void removeWrapper(String jspUri) {
        jsps.remove(jspUri);
    }

    /**
     * Returns the number of JSPs for which JspServletWrappers exist, i.e.,
     * the number of JSPs that have been loaded into the webapp.
     *
     * @return The number of JSPs that have been loaded into the webapp
     */
    public int getJspCount() {
        return jsps.size();
    }

    /**
     * Get the SecurityManager Policy CodeSource for this web
     * applicaiton context.
     *
     * @return CodeSource for JSP
     */
    public CodeSource getCodeSource() {
        return codeSource;
    }

    /**
     * Get the parent URLClassLoader.
     *
     * @return URLClassLoader parent
     */