org.apache.jasper.runtime.ProtectedFunctionMapper Maven / Gradle / Ivy
/*
* 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.lang.reflect.Method;
import java.util.HashMap;
/**
* 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 jakarta.el.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.
*
* @return A new protected function mapper.
*/
public static ProtectedFunctionMapper getInstance() {
ProtectedFunctionMapper funcMapper = new ProtectedFunctionMapper();
funcMapper.fnmap = new 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) {
// Skip if null values were passed in. They indicate a function
// added via a lambda or ImportHandler; nether of which need to be
// placed in the Map.
if (fnQName == null) {
return;
}
Method method;
try {
method = c.getMethod(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.
* @return the mapped function
*/
public static ProtectedFunctionMapper getMapForFunction(String fnQName,
final Class c, final String methodName, final Class[] args) {
Method method = null;
ProtectedFunctionMapper funcMapper = new ProtectedFunctionMapper();
// Skip if null values were passed in. They indicate a function
// added via a lambda or ImportHandler; nether of which need to be
// placed in the Map.
if (fnQName != null) {
try {
method = c.getMethod(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.
*/
@Override
public Method resolveFunction(String prefix, String localName) {
if (this.fnmap != null) {
return this.fnmap.get(prefix + ":" + localName);
}
return theMethod;
}
}