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Tomcat example source code file (JspRuntimeContext.java)

This example Tomcat source code file (JspRuntimeContext.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

codesource, file, filepermission, filepermission, io, jspfactoryimpl, jspruntimecontext, jspservletwrapper, jspservletwrapper, net, network, options, security, servlet, string, string, url, urlclassloader, urlclassloader, util

The Tomcat JspRuntimeContext.java source code

/*
 * 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();
 

    // ------------------------------------------------------ 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
     */
    public URLClassLoader getParentClassLoader() {
        return parentClassLoader;
    }

    /**
     * Get the SecurityManager PermissionCollection for this
     * web application context.
     *
     * @return PermissionCollection permissions
     */
    public PermissionCollection getPermissionCollection() {
        return permissionCollection;
    }

    /**
     * Process a "destory" event for this web application context.
     */                                                        
    public void destroy() {
        Iterator servlets = jsps.values().iterator();
        while (servlets.hasNext()) {
            ((JspServletWrapper) servlets.next()).destroy();
        }
    }

    /**
     * Increments the JSP reload counter.
     */
    public synchronized void incrementJspReloadCount() {
        jspReloadCount++;
    }

    /**
     * Resets the JSP reload counter.
     *
     * @param count Value to which to reset the JSP reload counter
     */
    public synchronized void setJspReloadCount(int count) {
        this.jspReloadCount = count;
    }

    /**
     * Gets the current value of the JSP reload counter.
     *
     * @return The current value of the JSP reload counter
     */
    public int getJspReloadCount() {
        return jspReloadCount;
    }


    /**
     * Method used by background thread to check the JSP dependencies
     * registered with this class for JSP's.
     */
    public void checkCompile() {

        if (lastCheck < 0) {
            // Checking was disabled
            return;
        }
        long now = System.currentTimeMillis();
        if (now > (lastCheck + (options.getCheckInterval() * 1000L))) {
            lastCheck = now;
        } else {
            return;
        }
        
        Object [] wrappers = jsps.values().toArray();
        for (int i = 0; i < wrappers.length; i++ ) {
            JspServletWrapper jsw = (JspServletWrapper)wrappers[i];
            JspCompilationContext ctxt = jsw.getJspEngineContext();
            // JspServletWrapper also synchronizes on this when
            // it detects it has to do a reload
            synchronized(jsw) {
                try {
                    ctxt.compile();
                } catch (FileNotFoundException ex) {
                    ctxt.incrementRemoved();
                } catch (Throwable t) {
                    jsw.getServletContext().log("Background compile failed",
						t);
                }
            }
        }

    }

    /**
     * The classpath that is passed off to the Java compiler.
     */
    public String getClassPath() {
        return classpath;
    }


    // -------------------------------------------------------- Private Methods


    /**
     * Method used to initialize classpath for compiles.
     */
    private void initClassPath() {

        URL [] urls = parentClassLoader.getURLs();
        StringBuffer cpath = new StringBuffer();
        String sep = System.getProperty("path.separator");

        for(int i = 0; i < urls.length; i++) {
            // Tomcat 4 can use URL's other than file URL's,
            // a protocol other than file: will generate a
            // bad file system path, so only add file:
            // protocol URL's to the classpath.
            
            if( urls[i].getProtocol().equals("file") ) {
                cpath.append((String)urls[i].getFile()+sep);
            }
        }    

	cpath.append(options.getScratchDir() + sep);

        String cp = (String) context.getAttribute(Constants.SERVLET_CLASSPATH);
        if (cp == null || cp.equals("")) {
            cp = options.getClassPath();
        }

        classpath = cpath.toString() + cp;

        if(log.isDebugEnabled()) {
            log.debug("Compilation classpath initialized: " + getClassPath());
        }
    }

    /**
     * Method used to initialize SecurityManager data.
     */
    private void initSecurity() {

        // Setup the PermissionCollection for this web app context
        // based on the permissions configured for the root of the
        // web app context directory, then add a file read permission
        // for that directory.
        Policy policy = Policy.getPolicy();
        if( policy != null ) {
            try {          
                // Get the permissions for the web app context
                String docBase = context.getRealPath("/");
                if( docBase == null ) {
                    docBase = options.getScratchDir().toString();
                }
                String codeBase = docBase;
                if (!codeBase.endsWith(File.separator)){
                    codeBase = codeBase + File.separator;
                }
                File contextDir = new File(codeBase);
                URL url = contextDir.getCanonicalFile().toURL();
                codeSource = new CodeSource(url,(Certificate[])null);
                permissionCollection = policy.getPermissions(codeSource);

                // Create a file read permission for web app context directory
                if (!docBase.endsWith(File.separator)){
                    permissionCollection.add
                        (new FilePermission(docBase,"read"));
                    docBase = docBase + File.separator;
                } else {
                    permissionCollection.add
                        (new FilePermission
                            (docBase.substring(0,docBase.length() - 1),"read"));
                }
                docBase = docBase + "-";
                permissionCollection.add(new FilePermission(docBase,"read"));

                // Create a file read permission for web app tempdir (work)
                // directory
                String workDir = options.getScratchDir().toString();
                if (!workDir.endsWith(File.separator)){
                    permissionCollection.add
                        (new FilePermission(workDir,"read"));
                    workDir = workDir + File.separator;
                }
                workDir = workDir + "-";
                permissionCollection.add(new FilePermission(workDir,"read"));

                // Allow the JSP to access org.apache.jasper.runtime.HttpJspBase
                permissionCollection.add( new RuntimePermission(
                    "accessClassInPackage.org.apache.jasper.runtime") );

                if (parentClassLoader instanceof URLClassLoader) {
                    URL [] urls = parentClassLoader.getURLs();
                    String jarUrl = null;
                    String jndiUrl = null;
                    for (int i=0; i<urls.length; i++) {
                        if (jndiUrl == null
                                && urls[i].toString().startsWith("jndi:") ) {
                            jndiUrl = urls[i].toString() + "-";
                        }
                        if (jarUrl == null
                                && urls[i].toString().startsWith("jar:jndi:")
                                ) {
                            jarUrl = urls[i].toString();
                            jarUrl = jarUrl.substring(0,jarUrl.length() - 2);
                            jarUrl = jarUrl.substring(0,
                                     jarUrl.lastIndexOf('/')) + "/-";
                        }
                    }
                    if (jarUrl != null) {
                        permissionCollection.add(
                                new FilePermission(jarUrl,"read"));
                        permissionCollection.add(
                                new FilePermission(jarUrl.substring(4),"read"));
                    }
                    if (jndiUrl != null)
                        permissionCollection.add(
                                new FilePermission(jndiUrl,"read") );
                }
            } catch(Exception e) {
                context.log("Security Init for context failed",e);
            }
        }
    }


}

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