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/*
* 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.lang3.reflect;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.ClassUtils;
import org.apache.commons.lang3.ClassUtils.Interfaces;
import org.apache.commons.lang3.Validate;
/**
* Utility reflection methods focused on {@link Method}s, 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 {@code public} methods contained in a default access superclass on JREs prior to 1.4.
* Reflection locates these methods fine and correctly assigns them as {@code public}.
* However, an {@link IllegalAccessException} is thrown if the method is invoked.
*
* {@link MethodUtils} contains a workaround for this situation.
* It will attempt to call {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} 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.
*
* @since 2.5
* @version $Id: MethodUtils.java 1534831 2013-10-22 22:41:06Z mbenson $
*/
public class MethodUtils {
/**
* {@link MethodUtils} instances should NOT be constructed in standard programming.
* Instead, the class should be used as
* {@code MethodUtils.getAccessibleMethod(method)}.
*
* This constructor is {@code public} to permit tools that require a JavaBean
* instance to operate.
*/
public MethodUtils() {
super();
}
/**
* Invokes 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 {@code Boolean} object
* would match a {@code 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(final Object object, final String methodName,
Object... args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
final Class[] parameterTypes = ClassUtils.toClass(args);
return invokeMethod(object, methodName, args, parameterTypes);
}
/**
* Invokes 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 {@code Boolean} object
* would match a {@code 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(final Object object, final String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
args = ArrayUtils.nullToEmpty(args);
final 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);
}
/**
* Invokes a 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 object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat {@code 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(final Object object, final String methodName,
Object... args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
final Class[] parameterTypes = ClassUtils.toClass(args);
return invokeExactMethod(object, methodName, args, parameterTypes);
}
/**
* Invokes a 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 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 {@code 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(final Object object, final String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
final 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);
}
/**
* Invokes a {@code 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 {@code null} as empty array
* @param parameterTypes match these parameters - treat {@code 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(final Class cls, final String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
final 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);
}
/**
* Invokes a named {@code 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 {@code Boolean} class
* would match a {@code boolean} primitive.
*
* This is a convenient wrapper for
* {@link #invokeStaticMethod(Class, String, Object[], Class[])}.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat {@code 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(final Class cls, final String methodName,
Object... args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
final Class[] parameterTypes = ClassUtils.toClass(args);
return invokeStaticMethod(cls, methodName, args, parameterTypes);
}
/**
* Invokes a named {@code 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 {@code Boolean} class
* would match a {@code boolean} primitive.
*
*
* @param cls invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat {@code null} as empty array
* @param parameterTypes match these parameters - treat {@code 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(final Class cls, final String methodName,
Object[] args, Class[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
final 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);
}
/**
* Invokes a {@code 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 {@code 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(final Class cls, final String methodName,
Object... args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
final Class[] parameterTypes = ClassUtils.toClass(args);
return invokeExactStaticMethod(cls, methodName, args, parameterTypes);
}
/**
* Returns 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 {@code null}.
* This is just a convenience wrapper for
* {@link #getAccessibleMethod(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(final Class cls, final String methodName,
final Class... parameterTypes) {
try {
return getAccessibleMethod(cls.getMethod(methodName,
parameterTypes));
} catch (final NoSuchMethodException e) {
return null;
}
}
/**
* Returns 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 {@code 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
final Class cls = method.getDeclaringClass();
if (Modifier.isPublic(cls.getModifiers())) {
return method;
}
final String methodName = method.getName();
final 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;
}
/**
* Returns 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 {@code 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 {@code null} if not found
*/
private static Method getAccessibleMethodFromSuperclass(final Class cls,
final String methodName, final Class... parameterTypes) {
Class parentClass = cls.getSuperclass();
while (parentClass != null) {
if (Modifier.isPublic(parentClass.getModifiers())) {
try {
return parentClass.getMethod(methodName, parameterTypes);
} catch (final NoSuchMethodException e) {
return null;
}
}
parentClass = parentClass.getSuperclass();
}
return null;
}
/**
* Returns 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 {@code null}.
*
* There isn't any good reason why this method must be {@code 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 {@code null} if not found
*/
private static Method getAccessibleMethodFromInterfaceNest(Class cls,
final String methodName, final Class... parameterTypes) {
// Search up the superclass chain
for (; cls != null; cls = cls.getSuperclass()) {
// Check the implemented interfaces of the parent class
final 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 {
return interfaces[i].getDeclaredMethod(methodName,
parameterTypes);
} catch (final NoSuchMethodException e) { // NOPMD
/*
* Swallow, if no method is found after the loop then this
* method returns null.
*/
}
// Recursively check our parent interfaces
Method method = getAccessibleMethodFromInterfaceNest(interfaces[i],
methodName, parameterTypes);
if (method != null) {
return method;
}
}
}
return null;
}
/**
* Finds 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 {@code Boolean} will match a primitive {@code 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(final Class cls,
final String methodName, final Class... parameterTypes) {
try {
final Method method = cls.getMethod(methodName, parameterTypes);
MemberUtils.setAccessibleWorkaround(method);
return method;
} catch (final NoSuchMethodException e) { // NOPMD - Swallow the exception
}
// search through all methods
Method bestMatch = null;
final Method[] methods = cls.getMethods();
for (final Method method : methods) {
// compare name and parameters
if (method.getName().equals(methodName) && ClassUtils.isAssignable(parameterTypes, method.getParameterTypes(), true)) {
// get accessible version of method
final Method accessibleMethod = getAccessibleMethod(method);
if (accessibleMethod != null && (bestMatch == null || MemberUtils.compareParameterTypes(
accessibleMethod.getParameterTypes(),
bestMatch.getParameterTypes(),
parameterTypes) < 0)) {
bestMatch = accessibleMethod;
}
}
}
if (bestMatch != null) {
MemberUtils.setAccessibleWorkaround(bestMatch);
}
return bestMatch;
}
/**
* Get the hierarchy of overridden methods down to {@code result} respecting generics.
* @param method lowest to consider
* @param interfacesBehavior whether to search interfaces, {@code null} {@code implies} false
* @return Set in ascending order from sub- to superclass
* @throws NullPointerException if the specified method is {@code null}
* @since 3.2
*/
public static Set getOverrideHierarchy(final Method method, Interfaces interfacesBehavior) {
Validate.notNull(method);
final Set result = new LinkedHashSet();
result.add(method);
final Class[] parameterTypes = method.getParameterTypes();
final Class declaringClass = method.getDeclaringClass();
final Iterator> hierarchy = ClassUtils.hierarchy(declaringClass, interfacesBehavior).iterator();
//skip the declaring class :P
hierarchy.next();
hierarchyTraversal: while (hierarchy.hasNext()) {
final Class c = hierarchy.next();
final Method m = getMatchingAccessibleMethod(c, method.getName(), parameterTypes);
if (m == null) {
continue;
}
if (Arrays.equals(m.getParameterTypes(), parameterTypes)) {
// matches without generics
result.add(m);
continue;
}
// necessary to get arguments every time in the case that we are including interfaces
final Map, Type> typeArguments = TypeUtils.getTypeArguments(declaringClass, m.getDeclaringClass());
for (int i = 0; i < parameterTypes.length; i++) {
final Type childType = TypeUtils.unrollVariables(typeArguments, method.getGenericParameterTypes()[i]);
final Type parentType = TypeUtils.unrollVariables(typeArguments, m.getGenericParameterTypes()[i]);
if (!TypeUtils.equals(childType, parentType)) {
continue hierarchyTraversal;
}
}
result.add(m);
}
return result;
}
}