Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance. Project price only 1 $
You can buy this project and download/modify it how often you want.
/*
* 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.el.util;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import javax.el.ELException;
import javax.el.MethodNotFoundException;
import org.apache.el.lang.ELSupport;
/**
* Utilities for Managing Serialization and Reflection
*
* @author Jacob Hookom [[email protected]]
* @version $Id: ReflectionUtil.java 1428408 2013-01-03 15:39:41Z markt $
*/
public class ReflectionUtil {
protected static final String[] PRIMITIVE_NAMES = new String[] { "boolean",
"byte", "char", "double", "float", "int", "long", "short", "void" };
protected static final Class[] PRIMITIVES = new Class[] { boolean.class,
byte.class, char.class, double.class, float.class, int.class,
long.class, short.class, Void.TYPE };
private ReflectionUtil() {
super();
}
public static Class forName(String name) throws ClassNotFoundException {
if (null == name || "".equals(name)) {
return null;
}
Class c = forNamePrimitive(name);
if (c == null) {
if (name.endsWith("[]")) {
String nc = name.substring(0, name.length() - 2);
c = Class.forName(nc, true, Thread.currentThread().getContextClassLoader());
c = Array.newInstance(c, 0).getClass();
} else {
c = Class.forName(name, true, Thread.currentThread().getContextClassLoader());
}
}
return c;
}
protected static Class forNamePrimitive(String name) {
if (name.length() <= 8) {
int p = Arrays.binarySearch(PRIMITIVE_NAMES, name);
if (p >= 0) {
return PRIMITIVES[p];
}
}
return null;
}
/**
* Converts an array of Class names to Class types
* @param s
* @throws ClassNotFoundException
*/
public static Class[] toTypeArray(String[] s) throws ClassNotFoundException {
if (s == null)
return null;
Class[] c = new Class[s.length];
for (int i = 0; i < s.length; i++) {
c[i] = forName(s[i]);
}
return c;
}
/**
* Converts an array of Class types to Class names
* @param c
*/
public static String[] toTypeNameArray(Class[] c) {
if (c == null)
return null;
String[] s = new String[c.length];
for (int i = 0; i < c.length; i++) {
s[i] = c[i].getName();
}
return s;
}
/**
* Returns a method based on the criteria
* @param base the object that owns the method
* @param property the name of the method
* @param paramTypes the parameter types to use
* @param paramValues the parameter values
* @return the method specified
* @throws MethodNotFoundException
*/
@SuppressWarnings("null")
public static Method getMethod(Object base, Object property,
Class[] paramTypes, Object[] paramValues)
throws MethodNotFoundException {
if (base == null || property == null) {
throw new MethodNotFoundException(MessageFactory.get(
"error.method.notfound", base, property,
paramString(paramTypes)));
}
String methodName = (property instanceof String) ? (String) property
: property.toString();
int paramCount;
if (paramTypes == null) {
paramCount = 0;
} else {
paramCount = paramTypes.length;
}
Method[] methods = base.getClass().getMethods();
Map candidates = new HashMap();
for (Method m : methods) {
if (!m.getName().equals(methodName)) {
// Method name doesn't match
continue;
}
Class[] mParamTypes = m.getParameterTypes();
int mParamCount;
if (mParamTypes == null) {
mParamCount = 0;
} else {
mParamCount = mParamTypes.length;
}
// Check the number of parameters
if (!(paramCount == mParamCount ||
(m.isVarArgs() && paramCount >= mParamCount))) {
// Method has wrong number of parameters
continue;
}
// Check the parameters match
int exactMatch = 0;
boolean noMatch = false;
for (int i = 0; i < mParamCount; i++) {
// Can't be null
if (mParamTypes[i].equals(paramTypes[i])) {
exactMatch++;
} else if (i == (mParamCount - 1) && m.isVarArgs()) {
Class varType = mParamTypes[i].getComponentType();
for (int j = i; j < paramCount; j++) {
if (!isAssignableFrom(paramTypes[j], varType)) {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (!isCoercibleFrom(paramValues[j], varType)) {
noMatch = true;
break;
}
}
}
// Don't treat a varArgs match as an exact match, it can
// lead to a varArgs method matching when the result
// should be ambiguous
}
} else if (!isAssignableFrom(paramTypes[i], mParamTypes[i])) {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (!isCoercibleFrom(paramValues[i], mParamTypes[i])) {
noMatch = true;
break;
}
}
}
}
if (noMatch) {
continue;
}
// If a method is found where every parameter matches exactly,
// return it
if (exactMatch == paramCount) {
return m;
}
candidates.put(m, Integer.valueOf(exactMatch));
}
// Look for the method that has the highest number of parameters where
// the type matches exactly
int bestMatch = 0;
Method match = null;
boolean multiple = false;
for (Map.Entry entry : candidates.entrySet()) {
if (entry.getValue().intValue() > bestMatch ||
match == null) {
bestMatch = entry.getValue().intValue();
match = entry.getKey();
multiple = false;
} else if (entry.getValue().intValue() == bestMatch) {
multiple = true;
}
}
if (multiple) {
if (bestMatch == paramCount - 1) {
// Only one parameter is not an exact match - try using the
// super class
match = resolveAmbiguousMethod(candidates.keySet(), paramTypes);
} else {
match = null;
}
if (match == null) {
// If multiple methods have the same matching number of parameters
// the match is ambiguous so throw an exception
throw new MethodNotFoundException(MessageFactory.get(
"error.method.ambiguous", base, property,
paramString(paramTypes)));
}
}
// Handle case where no match at all was found
if (match == null) {
throw new MethodNotFoundException(MessageFactory.get(
"error.method.notfound", base, property,
paramString(paramTypes)));
}
return match;
}
private static Method resolveAmbiguousMethod(Set candidates,
Class[] paramTypes) {
// Identify which parameter isn't an exact match
Method m = candidates.iterator().next();
int nonMatchIndex = 0;
Class nonMatchClass = null;
for (int i = 0; i < paramTypes.length; i++) {
if (m.getParameterTypes()[i] != paramTypes[i]) {
nonMatchIndex = i;
nonMatchClass = paramTypes[i];
break;
}
}
if (nonMatchClass == null) {
// Null will always be ambiguous
return null;
}
for (Method c : candidates) {
if (c.getParameterTypes()[nonMatchIndex] ==
paramTypes[nonMatchIndex]) {
// Methods have different non-matching parameters
// Result is ambiguous
return null;
}
}
// Can't be null
nonMatchClass = nonMatchClass.getSuperclass();
while (nonMatchClass != null) {
for (Method c : candidates) {
if (c.getParameterTypes()[nonMatchIndex].equals(
nonMatchClass)) {
// Found a match
return c;
}
}
nonMatchClass = nonMatchClass.getSuperclass();
}
return null;
}
// src will always be an object
private static boolean isAssignableFrom(Class src, Class target) {
// Short-cut. null is always assignable to an object and in EL null
// can always be coerced to a valid value for a primitive
if (src == null) {
return true;
}
Class targetClass;
if (target.isPrimitive()) {
if (target == Boolean.TYPE) {
targetClass = Boolean.class;
} else if (target == Character.TYPE) {
targetClass = Character.class;
} else if (target == Byte.TYPE) {
targetClass = Byte.class;
} else if (target == Short.TYPE) {
targetClass = Short.class;
} else if (target == Integer.TYPE) {
targetClass = Integer.class;
} else if (target == Long.TYPE) {
targetClass = Long.class;
} else if (target == Float.TYPE) {
targetClass = Float.class;
} else {
targetClass = Double.class;
}
} else {
targetClass = target;
}
return targetClass.isAssignableFrom(src);
}
private static boolean isCoercibleFrom(Object src, Class target) {
// TODO: This isn't pretty but it works. Significant refactoring would
// be required to avoid the exception.
try {
ELSupport.coerceToType(src, target);
} catch (ELException e) {
return false;
}
return true;
}
protected static final String paramString(Class[] types) {
if (types != null) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < types.length; i++) {
if (types[i] == null) {
sb.append("null, ");
} else {
sb.append(types[i].getName()).append(", ");
}
}
if (sb.length() > 2) {
sb.setLength(sb.length() - 2);
}
return sb.toString();
}
return null;
}
}
