Java tutorial
/* * $Header: /home/cvs/jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/core/ApplicationFilterConfig.java,v 1.7 2003/09/02 21:22:04 remm Exp $ * $Revision: 1.7 $ * $Date: 2003/09/02 21:22:04 $ * * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ package org.apache.catalina.core; import java.io.Serializable; import java.util.ArrayList; import java.util.Enumeration; import java.util.Map; import javax.servlet.Filter; import javax.servlet.FilterConfig; import javax.servlet.ServletContext; import javax.servlet.ServletException; import org.apache.catalina.Context; import org.apache.catalina.deploy.FilterDef; import org.apache.catalina.security.SecurityUtil; import org.apache.catalina.util.Enumerator; import org.apache.tomcat.util.log.SystemLogHandler; /** * Implementation of a <code>javax.servlet.FilterConfig</code> useful in * managing the filter instances instantiated when a web application * is first started. * * @author Craig R. McClanahan * @version $Revision: 1.7 $ $Date: 2003/09/02 21:22:04 $ */ final class ApplicationFilterConfig implements FilterConfig, Serializable { private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(ApplicationFilterConfig.class); // ----------------------------------------------------------- Constructors /** * Construct a new ApplicationFilterConfig for the specified filter * definition. * * @param context The context with which we are associated * @param filterDef Filter definition for which a FilterConfig is to be * constructed * * @exception ClassCastException if the specified class does not implement * the <code>javax.servlet.Filter</code> interface * @exception ClassNotFoundException if the filter class cannot be found * @exception IllegalAccessException if the filter class cannot be * publicly instantiated * @exception InstantiationException if an exception occurs while * instantiating the filter object * @exception ServletException if thrown by the filter's init() method */ public ApplicationFilterConfig(Context context, FilterDef filterDef) throws ClassCastException, ClassNotFoundException, IllegalAccessException, InstantiationException, ServletException { super(); this.context = context; setFilterDef(filterDef); } // ----------------------------------------------------- Instance Variables /** * The Context with which we are associated. */ private Context context = null; /** * The application Filter we are configured for. */ private transient Filter filter = null; /** * The <code>FilterDef</code> that defines our associated Filter. */ private FilterDef filterDef = null; // --------------------------------------------------- FilterConfig Methods /** * Return the name of the filter we are configuring. */ public String getFilterName() { return (filterDef.getFilterName()); } /** * Return a <code>String</code> containing the value of the named * initialization parameter, or <code>null</code> if the parameter * does not exist. * * @param name Name of the requested initialization parameter */ public String getInitParameter(String name) { Map map = filterDef.getParameterMap(); if (map == null) return (null); else return ((String) map.get(name)); } /** * Return an <code>Enumeration</code> of the names of the initialization * parameters for this Filter. */ public Enumeration getInitParameterNames() { Map map = filterDef.getParameterMap(); if (map == null) return (new Enumerator(new ArrayList())); else return (new Enumerator(map.keySet())); } /** * Return the ServletContext of our associated web application. */ public ServletContext getServletContext() { return (this.context.getServletContext()); } /** * Return a String representation of this object. */ public String toString() { StringBuffer sb = new StringBuffer("ApplicationFilterConfig["); sb.append("name="); sb.append(filterDef.getFilterName()); sb.append(", filterClass="); sb.append(filterDef.getFilterClass()); sb.append("]"); return (sb.toString()); } // -------------------------------------------------------- Package Methods /** * Return the application Filter we are configured for. * * @exception ClassCastException if the specified class does not implement * the <code>javax.servlet.Filter</code> interface * @exception ClassNotFoundException if the filter class cannot be found * @exception IllegalAccessException if the filter class cannot be * publicly instantiated * @exception InstantiationException if an exception occurs while * instantiating the filter object * @exception ServletException if thrown by the filter's init() method */ Filter getFilter() throws ClassCastException, ClassNotFoundException, IllegalAccessException, InstantiationException, ServletException { // Return the existing filter instance, if any if (this.filter != null) return (this.filter); // Identify the class loader we will be using String filterClass = filterDef.getFilterClass(); ClassLoader classLoader = null; if (filterClass.startsWith("org.apache.catalina.")) classLoader = this.getClass().getClassLoader(); else classLoader = context.getLoader().getClassLoader(); ClassLoader oldCtxClassLoader = Thread.currentThread().getContextClassLoader(); // Instantiate a new instance of this filter and return it Class clazz = classLoader.loadClass(filterClass); this.filter = (Filter) clazz.newInstance(); if (context instanceof StandardContext && ((StandardContext) context).getSwallowOutput()) { try { SystemLogHandler.startCapture(); filter.init(this); } finally { String log = SystemLogHandler.stopCapture(); if (log != null && log.length() > 0) { getServletContext().log(log); } } } else { filter.init(this); } return (this.filter); } /** * Return the filter definition we are configured for. */ FilterDef getFilterDef() { return (this.filterDef); } /** * Release the Filter instance associated with this FilterConfig, * if there is one. */ void release() { if (this.filter != null) { if (System.getSecurityManager() != null) { try { SecurityUtil.doAsPrivilege("destroy", filter); SecurityUtil.remove(filter); } catch (java.lang.Exception ex) { log.error("ApplicationFilterConfig.doAsPrivilege", ex); } } else { filter.destroy(); } } this.filter = null; } /** * Set the filter definition we are configured for. This has the side * effect of instantiating an instance of the corresponding filter class. * * @param filterDef The new filter definition * * @exception ClassCastException if the specified class does not implement * the <code>javax.servlet.Filter</code> interface * @exception ClassNotFoundException if the filter class cannot be found * @exception IllegalAccessException if the filter class cannot be * publicly instantiated * @exception InstantiationException if an exception occurs while * instantiating the filter object * @exception ServletException if thrown by the filter's init() method */ void setFilterDef(FilterDef filterDef) throws ClassCastException, ClassNotFoundException, IllegalAccessException, InstantiationException, ServletException { this.filterDef = filterDef; if (filterDef == null) { // Release any previously allocated filter instance if (this.filter != null) { if (System.getSecurityManager() != null) { try { SecurityUtil.doAsPrivilege("destroy", filter); SecurityUtil.remove(filter); } catch (java.lang.Exception ex) { log.error("ApplicationFilterConfig.doAsPrivilege", ex); } } else { filter.destroy(); } } this.filter = null; } else { // Allocate a new filter instance Filter filter = getFilter(); } } // -------------------------------------------------------- Private Methods }