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Tomcat example source code file (ProtectedFunctionMapper.java)

This example Tomcat source code file (ProtectedFunctionMapper.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

accesscontroller, accesscontroller, class, invalid, jsp, method, object, object, privilegedaction, privilegedactionexception, protectedfunctionmapper, protectedfunctionmapper, reflection, runtimeexception, runtimeexception, security, servlet, string, util

The Tomcat ProtectedFunctionMapper.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.runtime;

import java.util.HashMap;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.lang.reflect.Method;
import javax.servlet.jsp.el.FunctionMapper;

import org.apache.jasper.security.SecurityUtil;

/**
 * Maps EL functions to their Java method counterparts. Keeps the actual Method
 * objects protected so that JSP pages can't indirectly do reflection.
 * 
 * @author Mark Roth
 * @author Kin-man Chung
 */
public final class ProtectedFunctionMapper extends javax.el.FunctionMapper
        implements FunctionMapper {

    /**
     * Maps "prefix:name" to java.lang.Method objects.
     */
    private HashMap fnmap = null;

    /**
     * If there is only one function in the map, this is the Method for it.
     */
    private Method theMethod = null;

    /**
     * Constructor has protected access.
     */
    private ProtectedFunctionMapper() {
    }

    /**
     * Generated Servlet and Tag Handler implementations call this method to
     * retrieve an instance of the ProtectedFunctionMapper. This is necessary
     * since generated code does not have access to create instances of classes
     * in this package.
     * 
     * @return A new protected function mapper.
     */
    public static ProtectedFunctionMapper getInstance() {
        ProtectedFunctionMapper funcMapper;
        if (SecurityUtil.isPackageProtectionEnabled()) {
            funcMapper = (ProtectedFunctionMapper) AccessController
                    .doPrivileged(new PrivilegedAction() {
                        public Object run() {
                            return new ProtectedFunctionMapper();
                        }
                    });
        } else {
            funcMapper = new ProtectedFunctionMapper();
        }
        funcMapper.fnmap = new java.util.HashMap();
        return funcMapper;
    }

    /**
     * Stores a mapping from the given EL function prefix and name to the given
     * Java method.
     * 
     * @param fnQName
     *            The EL function qualified name (including prefix)
     * @param c
     *            The class containing the Java method
     * @param methodName
     *            The name of the Java method
     * @param args
     *            The arguments of the Java method
     * @throws RuntimeException
     *             if no method with the given signature could be found.
     */
    public void mapFunction(String fnQName, final Class c,
            final String methodName, final Class[] args) {
        java.lang.reflect.Method method;
        if (SecurityUtil.isPackageProtectionEnabled()) {
            try {
                method = (java.lang.reflect.Method) AccessController
                        .doPrivileged(new PrivilegedExceptionAction() {

                            public Object run() throws Exception {
                                return c.getDeclaredMethod(methodName, args);
                            }
                        });
            } catch (PrivilegedActionException ex) {
                throw new RuntimeException(
                        "Invalid function mapping - no such method: "
                                + ex.getException().getMessage());
            }
        } else {
            try {
                method = c.getDeclaredMethod(methodName, args);
            } catch (NoSuchMethodException e) {
                throw new RuntimeException(
                        "Invalid function mapping - no such method: "
                                + e.getMessage());
            }
        }

        this.fnmap.put(fnQName, method);
    }

    /**
     * Creates an instance for this class, and stores the Method for the given
     * EL function prefix and name. This method is used for the case when there
     * is only one function in the EL expression.
     * 
     * @param fnQName
     *            The EL function qualified name (including prefix)
     * @param c
     *            The class containing the Java method
     * @param methodName
     *            The name of the Java method
     * @param args
     *            The arguments of the Java method
     * @throws RuntimeException
     *             if no method with the given signature could be found.
     */
    public static ProtectedFunctionMapper getMapForFunction(String fnQName,
            final Class c, final String methodName, final Class[] args) {
        java.lang.reflect.Method method;
        ProtectedFunctionMapper funcMapper;
        if (SecurityUtil.isPackageProtectionEnabled()) {
            funcMapper = (ProtectedFunctionMapper) AccessController
                    .doPrivileged(new PrivilegedAction() {
                        public Object run() {
                            return new ProtectedFunctionMapper();
                        }
                    });

            try {
                method = (java.lang.reflect.Method) AccessController
                        .doPrivileged(new PrivilegedExceptionAction() {

                            public Object run() throws Exception {
                                return c.getDeclaredMethod(methodName, args);
                            }
                        });
            } catch (PrivilegedActionException ex) {
                throw new RuntimeException(
                        "Invalid function mapping - no such method: "
                                + ex.getException().getMessage());
            }
        } else {
            funcMapper = new ProtectedFunctionMapper();
            try {
                method = c.getDeclaredMethod(methodName, args);
            } catch (NoSuchMethodException e) {
                throw new RuntimeException(
                        "Invalid function mapping - no such method: "
                                + e.getMessage());
            }
        }
        funcMapper.theMethod = method;
        return funcMapper;
    }

    /**
     * Resolves the specified local name and prefix into a Java.lang.Method.
     * Returns null if the prefix and local name are not found.
     * 
     * @param prefix
     *            the prefix of the function
     * @param localName
     *            the short name of the function
     * @return the result of the method mapping. Null means no entry found.
     */
    public Method resolveFunction(String prefix, String localName) {
        if (this.fnmap != null) {
            return (Method) this.fnmap.get(prefix + ":" + localName);
        }
        return theMethod;
    }
}

Other Tomcat examples (source code examples)

Here is a short list of links related to this Tomcat ProtectedFunctionMapper.java source code file:

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