javax.el.ELProcessor 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 javax.el;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
/**
* @since EL 3.0
*/
public class ELProcessor {
private final ELManager manager = new ELManager();
private final ELContext context = manager.getELContext();
private final ExpressionFactory factory = ELManager.getExpressionFactory();
public ELManager getELManager() {
return manager;
}
public Object eval(String expression) {
return getValue(expression, Object.class);
}
public Object getValue(String expression, Class expectedType) {
ValueExpression ve = factory.createValueExpression(
context, bracket(expression), expectedType);
return ve.getValue(context);
}
public void setValue(String expression, Object value) {
ValueExpression ve = factory.createValueExpression(
context, bracket(expression), Object.class);
ve.setValue(context, value);
}
public void setVariable(String variable, String expression) {
if (expression == null) {
manager.setVariable(variable, null);
} else {
ValueExpression ve = factory.createValueExpression(
context, bracket(expression), Object.class);
manager.setVariable(variable, ve);
}
}
public void defineFunction(String prefix, String function, String className,
String methodName) throws ClassNotFoundException,
NoSuchMethodException {
if (prefix == null || function == null || className == null ||
methodName == null) {
throw new NullPointerException(Util.message(
context, "elProcessor.defineFunctionNullParams"));
}
// Check the imports
Class clazz = context.getImportHandler().resolveClass(className);
if (clazz == null) {
clazz = Class.forName(className, true,
Thread.currentThread().getContextClassLoader());
}
if (!Modifier.isPublic(clazz.getModifiers())) {
throw new ClassNotFoundException(Util.message(context,
"elProcessor.defineFunctionInvalidClass", className));
}
MethodSignature sig =
new MethodSignature(context, methodName, className);
Method methods[] = clazz.getMethods();
for (Method method : methods) {
if (!Modifier.isStatic(method.getModifiers())) {
continue;
}
if (method.getName().equals(sig.getName())) {
if (sig.getParamTypeNames() == null) {
manager.mapFunction(prefix, function, method);
return;
} else {
Class[] types = method.getParameterTypes();
String[] typeNames = sig.getParamTypeNames();
if (types.length == typeNames.length) {
boolean match = true;
for (int i = 0; i < types.length; i++) {
if (!types[i].getName().equals(typeNames[i])) {
match = false;
break;
}
}
if (match) {
manager.mapFunction(prefix, function, method);
return;
}
}
}
}
}
throw new NoSuchMethodException(Util.message(context,
"elProcessor.defineFunctionNoMethod", methodName, className));
}
/**
* @throws NullPointerException
* If any of the arguments are null
* @throws NoSuchMethodException
* If the method is not static
*/
public void defineFunction(String prefix, String function, Method method)
throws java.lang.NoSuchMethodException {
if (prefix == null || function == null || method == null) {
throw new NullPointerException(Util.message(
context, "elProcessor.defineFunctionNullParams"));
}
int modifiers = method.getModifiers();
// Check for public method as well as being static
if (!Modifier.isStatic(modifiers) || !Modifier.isPublic(modifiers)) {
throw new NoSuchMethodException(Util.message(context,
"elProcessor.defineFunctionInvalidMethod", method.getName(),
method.getDeclaringClass().getName()));
}
manager.mapFunction(prefix, function, method);
}
public void defineBean(String name, Object bean) {
manager.defineBean(name, bean);
}
private static String bracket(String expression) {
return "${" + expression + "}";
}
private static class MethodSignature {
private final String name;
private final String[] parameterTypeNames;
public MethodSignature(ELContext context, String methodName,
String className) throws NoSuchMethodException {
int paramIndex = methodName.indexOf('(');
if (paramIndex == -1) {
name = methodName.trim();
parameterTypeNames = null;
} else {
name = methodName.substring(0, paramIndex -1).trim();
String paramString = methodName.substring(paramIndex).trim();
// We know the params start with '(', check they end with ')'
if (!paramString.endsWith(")")) {
throw new NoSuchMethodException(Util.message(context,
"elProcessor.defineFunctionInvalidParameterList",
paramString, methodName, className));
}
// Trim '(' and ')'
paramString =
paramString.substring(1, paramString.length() - 1);
parameterTypeNames = paramString.split(",");
ImportHandler importHandler = context.getImportHandler();
for (int i = 0; i < parameterTypeNames.length; i++) {
parameterTypeNames[i] = parameterTypeNames[i].trim();
if (!parameterTypeNames[i].contains(".")) {
Class clazz = importHandler.resolveClass(
parameterTypeNames[i]);
if (clazz == null) {
throw new NoSuchMethodException(Util.message(
context,
"elProcessor.defineFunctionInvalidParameterTypeName",
parameterTypeNames[i], methodName,
className));
}
parameterTypeNames[i] = clazz.getName();
}
}
}
}
public String getName() {
return name;
}
/**
* @return null if just the method name was specified, an
* empty List if an empty parameter list was specified - i.e. ()
* - otherwise an ordered list of parameter type names
*/
public String[] getParamTypeNames() {
return parameterTypeNames;
}
}
}
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