org.apache.commons.lang.reflect.MethodUtils 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.commons.lang.reflect;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.ClassUtils;
/**
* Utility reflection methods focused on methods, originally from Commons BeanUtils.
* Differences from the BeanUtils version may be noted, especially where similar functionality
* already existed within Lang.
*
*
* Known Limitations
* Accessing Public Methods In A Default Access Superclass
* There is an issue when invoking public methods contained in a default access superclass on JREs prior to 1.4.
* Reflection locates these methods fine and correctly assigns them as public.
* However, an IllegalAccessException is thrown if the method is invoked.
*
* MethodUtils contains a workaround for this situation.
* It will attempt to call setAccessible on this method.
* If this call succeeds, then the method can be invoked as normal.
* This call will only succeed when the application has sufficient security privileges.
* If this call fails then the method may fail.
*
* @author Apache Software Foundation
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
* @author Rey François
* @author Gregor Raýman
* @author Jan Sorensen
* @author Robert Burrell Donkin
* @author Matt Benson
* @since 2.5
* @version $Id: MethodUtils.java 911986 2010-02-19 21:19:05Z niallp $
*/
public class MethodUtils {
/**
* MethodUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as
* MethodUtils.getAccessibleMethod(method).
*
* This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public MethodUtils() {
super();
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean object
* would match a boolean primitive.
*
* This is a convenient wrapper for
* {@link #invokeMethod(Object object, String methodName, Object[] args)}.
*
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param arg use this argument
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the method invoked
* @throws IllegalAccessException if the requested method is not accessible via reflection
*/
public static Object invokeMethod(Object object, String methodName,
Object arg) throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
return invokeMethod(object, methodName, new Object[] { arg });
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean object
* would match a boolean primitive.
*
* This is a convenient wrapper for
* {@link #invokeMethod(Object object,String methodName, Object[] args, Class[] parameterTypes)}.
*
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the method invoked
* @throws IllegalAccessException if the requested method is not accessible via reflection
*/
public static Object invokeMethod(Object object, String methodName,
Object[] args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] parameterTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
parameterTypes[i] = args[i].getClass();
}
return invokeMethod(object, methodName, args, parameterTypes);
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean object
* would match a boolean primitive.
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param parameterTypes match these parameters - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the method invoked
* @throws IllegalAccessException if the requested method is not accessible via reflection
*/
public static Object invokeMethod(Object object, String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
if (parameterTypes == null) {
parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
}
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
Method method = getMatchingAccessibleMethod(object.getClass(),
methodName, parameterTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: "
+ methodName + "() on object: "
+ object.getClass().getName());
}
return method.invoke(object, args);
}
/**
* Invoke a method whose parameter type matches exactly the object
* type.
*
* This is a convenient wrapper for
* {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
*
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param arg use this argument
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactMethod(Object object, String methodName,
Object arg) throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
return invokeExactMethod(object, methodName, new Object[] { arg });
}
/**
* Invoke a method whose parameter types match exactly the object
* types.
*
* This uses reflection to invoke the method obtained from a call to
* getAccessibleMethod().
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactMethod(Object object, String methodName,
Object[] args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] parameterTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
parameterTypes[i] = args[i].getClass();
}
return invokeExactMethod(object, methodName, args, parameterTypes);
}
/**
* Invoke a method whose parameter types match exactly the parameter
* types given.
*
* This uses reflection to invoke the method obtained from a call to
* getAccessibleMethod().
*
* @param object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param parameterTypes match these parameters - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactMethod(Object object, String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
if (parameterTypes == null) {
parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
}
Method method = getAccessibleMethod(object.getClass(), methodName,
parameterTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: "
+ methodName + "() on object: "
+ object.getClass().getName());
}
return method.invoke(object, args);
}
/**
* Invoke a static method whose parameter types match exactly the parameter
* types given.
*
* This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod(Class, String, Class[])}.
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param parameterTypes match these parameters - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactStaticMethod(Class cls, String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
if (parameterTypes == null) {
parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
}
Method method = getAccessibleMethod(cls, methodName, parameterTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: "
+ methodName + "() on class: " + cls.getName());
}
return method.invoke(null, args);
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean class
* would match a boolean primitive.
*
* This is a convenient wrapper for
* {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args)}.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param arg use this argument
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeStaticMethod(Class cls, String methodName,
Object arg) throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
return invokeStaticMethod(cls, methodName, new Object[] { arg });
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean class
* would match a boolean primitive.
*
* This is a convenient wrapper for
* {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes)}.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeStaticMethod(Class cls, String methodName,
Object[] args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] parameterTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
parameterTypes[i] = args[i].getClass();
}
return invokeStaticMethod(cls, methodName, args, parameterTypes);
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* This method supports calls to methods taking primitive parameters
* via passing in wrapping classes. So, for example, a Boolean class
* would match a boolean primitive.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param parameterTypes match these parameters - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeStaticMethod(Class cls, String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
if (parameterTypes == null) {
parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
}
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
Method method = getMatchingAccessibleMethod(cls, methodName,
parameterTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: "
+ methodName + "() on class: " + cls.getName());
}
return method.invoke(null, args);
}
/**
* Invoke a static method whose parameter type matches exactly the object
* type.
*
* This is a convenient wrapper for
* {@link #invokeExactStaticMethod(Class objectClass,String methodName,Object [] args)}.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param arg use this argument
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactStaticMethod(Class cls, String methodName,
Object arg) throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
return invokeExactStaticMethod(cls, methodName, new Object[] { arg });
}
/**
* Invoke a static method whose parameter types match exactly the object
* types.
*
* This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod(Class, String, Class[])}.
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @return The value returned by the invoked method
*
* @throws NoSuchMethodException if there is no such accessible method
* @throws InvocationTargetException wraps an exception thrown by the
* method invoked
* @throws IllegalAccessException if the requested method is not accessible
* via reflection
*/
public static Object invokeExactStaticMethod(Class cls, String methodName,
Object[] args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
if (args == null) {
args = ArrayUtils.EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] parameterTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
parameterTypes[i] = args[i].getClass();
}
return invokeExactStaticMethod(cls, methodName, args, parameterTypes);
}
/**
* Return an accessible method (that is, one that can be invoked via
* reflection) with given name and a single parameter. If no such method
* can be found, return null.
* Basically, a convenience wrapper that constructs a Class
* array for you.
*
* @param cls get method from this class
* @param methodName get method with this name
* @param parameterType taking this type of parameter
* @return The accessible method
*/
public static Method getAccessibleMethod(Class cls, String methodName,
Class parameterType) {
return getAccessibleMethod(cls, methodName,
new Class[] { parameterType });
}
/**
* Return an accessible method (that is, one that can be invoked via
* reflection) with given name and parameters. If no such method
* can be found, return null.
* This is just a convenient wrapper for
* {@link #getAccessibleMethod(Method method)}.
*
* @param cls get method from this class
* @param methodName get method with this name
* @param parameterTypes with these parameters types
* @return The accessible method
*/
public static Method getAccessibleMethod(Class cls, String methodName,
Class[] parameterTypes) {
try {
return getAccessibleMethod(cls.getMethod(methodName,
parameterTypes));
} catch (NoSuchMethodException e) {
return (null);
}
}
/**
* Return an accessible method (that is, one that can be invoked via
* reflection) that implements the specified Method. If no such method
* can be found, return null.
*
* @param method The method that we wish to call
* @return The accessible method
*/
public static Method getAccessibleMethod(Method method) {
if (!MemberUtils.isAccessible(method)) {
return null;
}
// If the declaring class is public, we are done
Class cls = method.getDeclaringClass();
if (Modifier.isPublic(cls.getModifiers())) {
return method;
}
String methodName = method.getName();
Class[] parameterTypes = method.getParameterTypes();
// Check the implemented interfaces and subinterfaces
method = getAccessibleMethodFromInterfaceNest(cls, methodName,
parameterTypes);
// Check the superclass chain
if (method == null) {
method = getAccessibleMethodFromSuperclass(cls, methodName,
parameterTypes);
}
return method;
}
/**
* Return an accessible method (that is, one that can be invoked via
* reflection) by scanning through the superclasses. If no such method
* can be found, return null.
*
* @param cls Class to be checked
* @param methodName Method name of the method we wish to call
* @param parameterTypes The parameter type signatures
* @return the accessible method or null if not found
*/
private static Method getAccessibleMethodFromSuperclass(Class cls,
String methodName, Class[] parameterTypes) {
Class parentClass = cls.getSuperclass();
while (parentClass != null) {
if (Modifier.isPublic(parentClass.getModifiers())) {
try {
return parentClass.getMethod(methodName, parameterTypes);
} catch (NoSuchMethodException e) {
return null;
}
}
parentClass = parentClass.getSuperclass();
}
return null;
}
/**
* Return an accessible method (that is, one that can be invoked via
* reflection) that implements the specified method, by scanning through
* all implemented interfaces and subinterfaces. If no such method
* can be found, return null.
*
* There isn't any good reason why this method must be private.
* It is because there doesn't seem any reason why other classes should
* call this rather than the higher level methods.
*
* @param cls Parent class for the interfaces to be checked
* @param methodName Method name of the method we wish to call
* @param parameterTypes The parameter type signatures
* @return the accessible method or null if not found
*/
private static Method getAccessibleMethodFromInterfaceNest(Class cls,
String methodName, Class[] parameterTypes) {
Method method = null;
// Search up the superclass chain
for (; cls != null; cls = cls.getSuperclass()) {
// Check the implemented interfaces of the parent class
Class[] interfaces = cls.getInterfaces();
for (int i = 0; i < interfaces.length; i++) {
// Is this interface public?
if (!Modifier.isPublic(interfaces[i].getModifiers())) {
continue;
}
// Does the method exist on this interface?
try {
method = interfaces[i].getDeclaredMethod(methodName,
parameterTypes);
} catch (NoSuchMethodException e) {
/*
* Swallow, if no method is found after the loop then this
* method returns null.
*/
}
if (method != null) {
break;
}
// Recursively check our parent interfaces
method = getAccessibleMethodFromInterfaceNest(interfaces[i],
methodName, parameterTypes);
if (method != null) {
break;
}
}
}
return method;
}
/**
* Find an accessible method that matches the given name and has compatible parameters.
* Compatible parameters mean that every method parameter is assignable from
* the given parameters.
* In other words, it finds a method with the given name
* that will take the parameters given.
*
*
This method is used by
* {@link
* #invokeMethod(Object object, String methodName, Object[] args, Class[] parameterTypes)}.
*
*
This method can match primitive parameter by passing in wrapper classes.
* For example, a Boolean will match a primitive boolean
* parameter.
*
* @param cls find method in this class
* @param methodName find method with this name
* @param parameterTypes find method with most compatible parameters
* @return The accessible method
*/
public static Method getMatchingAccessibleMethod(Class cls,
String methodName, Class[] parameterTypes) {
try {
Method method = cls.getMethod(methodName, parameterTypes);
MemberUtils.setAccessibleWorkaround(method);
return method;
} catch (NoSuchMethodException e) { /* SWALLOW */
}
// search through all methods
Method bestMatch = null;
Method[] methods = cls.getMethods();
for (int i = 0, size = methods.length; i < size; i++) {
if (methods[i].getName().equals(methodName)) {
// compare parameters
if (ClassUtils.isAssignable(parameterTypes, methods[i]
.getParameterTypes(), true)) {
// get accessible version of method
Method accessibleMethod = getAccessibleMethod(methods[i]);
if (accessibleMethod != null) {
if (bestMatch == null
|| MemberUtils.compareParameterTypes(
accessibleMethod.getParameterTypes(),
bestMatch.getParameterTypes(),
parameterTypes) < 0) {
bestMatch = accessibleMethod;
}
}
}
}
}
if (bestMatch != null) {
MemberUtils.setAccessibleWorkaround(bestMatch);
}
return bestMatch;
}
}