com.aspectran.core.util.MethodUtils Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2023 The Aspectran Project
*
* Licensed 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 com.aspectran.core.util;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Locale;
import java.util.Map;
/**
* Utility reflection methods.
*/
public class MethodUtils {
/** An empty class array */
public static final Class[] EMPTY_CLASS_PARAMETERS = {};
/** An empty object array */
public static final Object[] EMPTY_OBJECT_ARRAY = {};
public static final Method[] NO_METHODS = {};
/** Stores a cache of MethodDescriptor -> Method. */
private static final Map cache = new ConcurrentReferenceHashMap<>(256);
/**
* Sets the value of a bean property to an Object.
*
* @param object the bean to change
* @param setterName the property name or setter method name
* @param arg use this argument
* @throws NoSuchMethodException the no such method exception
* @throws IllegalAccessException the illegal access exception
* @throws InvocationTargetException the invocation target exception
*/
public static void invokeSetter(Object object, String setterName, Object arg)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
Object[] args = { arg };
invokeSetter(object, setterName, args);
}
/**
* Sets the value of a bean property to an Object.
*
* @param object the bean to change
* @param setterName the property name or setter method name
* @param args use this arguments
* @throws NoSuchMethodException the no such method exception
* @throws IllegalAccessException the illegal access exception
* @throws InvocationTargetException the invocation target exception
*/
public static void invokeSetter(Object object, String setterName, Object[] args)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
int index = setterName.indexOf('.');
if (index > 0) {
String getterName = setterName.substring(0, index);
Object o = invokeGetter(object, getterName);
invokeSetter(o, setterName.substring(index + 1), args);
} else {
if (!setterName.startsWith("set")) {
setterName = "set" + setterName.substring(0, 1).toUpperCase(Locale.US) + setterName.substring(1);
}
invokeMethod(object, setterName, args);
}
}
/**
* Gets an Object property from a bean.
*
* @param object the bean
* @param getterName the property name or getter method name
* @return the property value (as an Object)
* @throws NoSuchMethodException the no such method exception
* @throws IllegalAccessException the illegal access exception
* @throws InvocationTargetException the invocation target exception
*/
public static Object invokeGetter(Object object, String getterName)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
return invokeMethod(object, getterName);
}
/**
* Gets an Object property from a bean.
*
* @param object the bean
* @param getterName the property name or getter method name
* @param arg use this argument
* @return the property value (as an Object)
* @throws NoSuchMethodException the no such method exception
* @throws IllegalAccessException the illegal access exception
* @throws InvocationTargetException the invocation target exception
*/
public static Object invokeGetter(Object object, String getterName, Object arg)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
Object[] args = { arg };
return invokeGetter(object, getterName, args);
}
/**
* Gets an Object property from a bean.
*
* @param object the bean
* @param getterName the property name or getter method name
* @param args use this arguments
* @return the property value (as an Object)
* @throws NoSuchMethodException the no such method exception
* @throws IllegalAccessException the illegal access exception
* @throws InvocationTargetException the invocation target exception
*/
public static Object invokeGetter(Object object, String getterName, Object[] args)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
int index = getterName.indexOf('.');
if (index > 0) {
String getterName2 = getterName.substring(0, index);
Object o = invokeGetter(object, getterName2);
return invokeGetter(o, getterName.substring(index + 1), args);
} else {
if (!getterName.startsWith("get") && !getterName.startsWith("is")) {
getterName = "get" + getterName.substring(0, 1).toUpperCase(Locale.US) + getterName.substring(1);
}
return invokeMethod(object, getterName, args);
}
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* @param object invoke method on this object
* @param methodName get method with this name
* @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
*/
public static Object invokeMethod(Object object, String methodName)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
return invokeMethod(object, methodName, EMPTY_OBJECT_ARRAY, EMPTY_CLASS_PARAMETERS);
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@code invokeExactMethod()}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 #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 {
Object[] args = { arg };
return invokeMethod(object, methodName, args);
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@link #invokeExactMethod(Object object,String methodName,Object[] args)}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 #invokeMethod(Object object,String methodName,Object[] args,Class[] paramTypes)}.
*
*
* @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 {
Class[] paramTypes;
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
paramTypes = EMPTY_CLASS_PARAMETERS;
} else {
int len = args.length;
if (len == 0) {
paramTypes = EMPTY_CLASS_PARAMETERS;
} else {
paramTypes = new Class[len];
for (int i = 0; i < len; i++) {
if (args[i] != null) {
paramTypes[i] = args[i].getClass();
}
}
}
}
return invokeMethod(object, methodName, args, paramTypes);
}
/**
* Invoke a named method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@link
* #invokeExactMethod(Object object,String methodName,Object[] args,Class[] paramTypes)}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 object invoke method on this object
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param paramTypes 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[] paramTypes)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
if (paramTypes == null) {
paramTypes = EMPTY_CLASS_PARAMETERS;
}
Method method = getMatchingAccessibleMethod(object.getClass(), methodName, args, paramTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: " + methodName + "() on object: " + object.getClass().getName());
}
return invokeMethod(object, method, args, paramTypes);
}
/**
* 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 {
Object[] args = { arg };
return invokeExactMethod(object, methodName, args);
}
/**
* Invoke a method whose parameter types match exactly the object types.
*
* This uses reflection to invoke the method obtained from a call to
* {@code 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 {
Class[] paramTypes;
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
paramTypes = EMPTY_CLASS_PARAMETERS;
} else {
int arguments = args.length;
if (arguments == 0) {
paramTypes = EMPTY_CLASS_PARAMETERS;
} else {
paramTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
if (args[i] != null)
paramTypes[i] = args[i].getClass();
}
}
}
return invokeExactMethod(object, methodName, args, paramTypes);
}
/**
* Invoke a method whose parameter types match exactly the parameter types given.
*
* This uses reflection to invoke the method obtained from a call to
* {@code 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 paramTypes 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[] paramTypes)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
if (paramTypes == null) {
paramTypes = EMPTY_CLASS_PARAMETERS;
}
Method method = getAccessibleMethod(object.getClass(), methodName, paramTypes);
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 objectClass invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param paramTypes 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 objectClass, String methodName, Object[] args,
Class[] paramTypes)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
if (paramTypes == null) {
paramTypes = EMPTY_CLASS_PARAMETERS;
}
Method method = getAccessibleMethod(objectClass, methodName, paramTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: " + methodName + "() on class: " +
objectClass.getName());
}
return method.invoke(null, args);
}
/**
* Invoke a named static method that has no parameters.
*
* @param objectClass invoke static method on this class
* @param methodName get method with this name
* @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 objectClass, String methodName)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
return invokeStaticMethod(objectClass, methodName, EMPTY_OBJECT_ARRAY, EMPTY_CLASS_PARAMETERS);
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@link #invokeExactMethod(Object, String, Object[], Class[])}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 objectClass,String methodName,Object[] args)}.
*
*
* @param objectClass 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 objectClass, String methodName, Object arg)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
Object[] args = { arg };
return invokeStaticMethod(objectClass, methodName, args);
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@link #invokeExactMethod(Object object,String methodName,Object[] args)}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 objectClass,String methodName,Object[] args,Class[] paramTypes)}.
*
*
* @param objectClass 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 objectClass, String methodName, Object[] args)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] paramTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
paramTypes[i] = args[i].getClass();
}
return invokeStaticMethod(objectClass, methodName, args, paramTypes);
}
/**
* Invoke a named static method whose parameter type matches the object type.
*
* The behaviour of this method is less deterministic
* than {@link #invokeExactStaticMethod(Class objectClass,String methodName,Object[] args,Class[] paramTypes)}.
* It loops through all methods with names that match
* and then executes the first it finds with compatible parameters.
*
* 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 objectClass invoke static method on this class
* @param methodName get method with this name
* @param args use these arguments - treat null as empty array
* @param paramTypes 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 objectClass, String methodName, Object[] args,
Class[] paramTypes)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
if (paramTypes == null) {
paramTypes = EMPTY_CLASS_PARAMETERS;
}
Method method = getMatchingAccessibleMethod(objectClass, methodName, args, paramTypes);
if (method == null) {
throw new NoSuchMethodException("No such accessible method: " + methodName + "() on class: " +
objectClass.getName());
}
return invokeMethod(null, method, args, paramTypes);
}
/**
* Invoke a static method that has no parameters.
*
* @param objectClass invoke static method on this class
* @param methodName get method with this name
* @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 objectClass, String methodName)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
return invokeExactStaticMethod(objectClass, methodName, EMPTY_OBJECT_ARRAY, EMPTY_CLASS_PARAMETERS);
}
/**
* 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 objectClass 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 objectClass, String methodName, Object arg)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
Object[] args = { arg };
return invokeExactStaticMethod(objectClass, methodName, args);
}
/**
* 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 objectClass 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 objectClass, String methodName, Object[] args)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
if (args == null) {
args = EMPTY_OBJECT_ARRAY;
}
int arguments = args.length;
Class[] paramTypes = new Class[arguments];
for (int i = 0; i < arguments; i++) {
paramTypes[i] = args[i].getClass();
}
return invokeExactStaticMethod(objectClass, methodName, args, paramTypes);
}
private static Object invokeMethod(Object object, Method method, Object[] args, Class[] paramTypes)
throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
Class[] methodsParams = method.getParameterTypes();
return invokeMethod(object, method, methodsParams, args, paramTypes);
}
private static Object invokeMethod(Object object, Method method, Class[] methodsParams, Object[] args,
Class[] paramTypes)
throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
if (methodsParams != null && methodsParams.length > 0) {
Object[] args2 = new Object[methodsParams.length];
for (int i = 0; i < methodsParams.length; i++) {
args2[i] = args[i];
if (paramTypes[i] != null && methodsParams[i].isArray()) {
Class methodParamType = methodsParams[i].getComponentType();
Class argParamType = paramTypes[i].getComponentType();
if (!methodParamType.equals(argParamType)) {
args2[i] = ReflectionUtils.toComponentTypeArray(args2[i], methodParamType);
}
}
}
return method.invoke(object, args2);
} else {
return method.invoke(object, args);
}
}
/**
* 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 {@code null}.
* Basically, a convenience wrapper that constructs a {@code Class}
* array for you.
*
* @param clazz get method from this class
* @param methodName get method with this name
* @return the accessible method
*/
public static Method getAccessibleMethod(Class clazz, String methodName) {
return getAccessibleMethod(clazz, methodName, EMPTY_CLASS_PARAMETERS);
}
/**
* 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 {@code null}.
* Basically, a convenience wrapper that constructs a {@code Class}
* array for you.
*
* @param clazz get method from this class
* @param methodName get method with this name
* @param paramType taking this type of parameter
* @return the accessible method
*/
public static Method getAccessibleMethod(Class clazz, String methodName, Class paramType) {
Class[] paramTypes = { paramType };
return getAccessibleMethod(clazz, methodName, paramTypes);
}
/**
* 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 {@code null}.
* This is just a convenient wrapper for
* {@link #getAccessibleMethod(Method method)}.
*
* @param clazz get method from this class
* @param methodName get method with this name
* @param paramTypes with these parameters types
* @return the accessible method
*/
public static Method getAccessibleMethod(Class clazz, String methodName, Class[] paramTypes) {
MethodDescriptor md = new MethodDescriptor(clazz, methodName, paramTypes, true);
Method[] result = cache.get(md);
if (result == null) {
try {
Method method = getAccessibleMethod(clazz.getMethod(methodName, paramTypes));
result = new Method[] { method };
} catch (NoSuchMethodException e) {
result = NO_METHODS;
}
cache.put(md, result);
}
return (result.length > 0 ? result[0] : 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 {@code null}.
*
* @param method the method that we wish to call
* @return the accessible method
*/
public static Method getAccessibleMethod(Method method) {
// Make sure we have a method to check
if (method == null) {
return null;
}
return getAccessibleMethod(method.getDeclaringClass(), method);
}
/**
* 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 {@code null}.
*
* @param clazz The class of the object
* @param method The method that we wish to call
* @return the accessible method
*/
public static Method getAccessibleMethod(Class clazz, Method method) {
// Make sure we have a method to check
if (method == null) {
return null;
}
// If the requested method is not public we cannot call it
if (!Modifier.isPublic(method.getModifiers())) {
return null;
}
if (clazz == null) {
clazz = method.getDeclaringClass();
} else if (!method.getDeclaringClass().isAssignableFrom(clazz)) {
throw new IllegalArgumentException(clazz.getName() + " is not assignable from " +
method.getDeclaringClass().getName());
}
// If the class is public, we are done
if (Modifier.isPublic(clazz.getModifiers())) {
return method;
}
String methodName = method.getName();
Class[] paramTypes = method.getParameterTypes();
// Check the implemented interfaces and sub interfaces
method = getAccessibleMethodFromInterfaceNest(clazz, methodName, paramTypes);
// Check the superclass chain
if (method == null) {
method = getAccessibleMethodFromSuperclass(clazz, methodName, paramTypes);
}
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 {@code null}.
*
* @param clazz Class to be checked
* @param methodName Method name of the method we wish to call
* @param paramTypes The parameter type signatures
*/
private static Method getAccessibleMethodFromSuperclass(Class clazz, String methodName, Class[] paramTypes) {
Class parentClazz = clazz.getSuperclass();
while (parentClazz != null) {
if (Modifier.isPublic(parentClazz.getModifiers())) {
try {
return parentClazz.getMethod(methodName, paramTypes);
} catch (NoSuchMethodException e) {
return null;
}
}
parentClazz = parentClazz.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 {@code 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 clazz Parent class for the interfaces to be checked
* @param methodName Method name of the method we wish to call
* @param paramTypes The parameter type signatures
*/
private static Method getAccessibleMethodFromInterfaceNest(Class clazz, String methodName,
Class[] paramTypes) {
Method method = null;
// Search up the superclass chain
for (; clazz != null; clazz = clazz.getSuperclass()) {
// Check the implemented interfaces of the parent class
Class[] interfaces = clazz.getInterfaces();
for (Class anInterface : interfaces) {
// Is this interface public?
if (!Modifier.isPublic(anInterface.getModifiers())) {
continue;
}
// Does the method exist on this interface?
try {
method = anInterface.getDeclaredMethod(methodName, paramTypes);
} catch (NoSuchMethodException e) {
/* Swallow, if no method is found after the loop then this
* method returns null.
*/
}
if (method != null) {
return method;
}
// Recursively check our parent interfaces
method = getAccessibleMethodFromInterfaceNest(anInterface, methodName, paramTypes);
if (method != null) {
return method;
}
}
}
// We did not find anything
return null;
}
/**
* 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 slightly undeterminstic since it loops
* through methods names and return the first matching method.
*
* This method is used by
* {@link #invokeMethod(Object object,String methodName,Object[] args,Class[] paramTypes)}.
*
*
This method can match primitive parameter by passing in wrapper classes.
* For example, a {@code Boolean} will match a primitive {@code boolean}
* parameter.
*
* @param clazz find method in this class
* @param methodName find method with this name
* @param args find method with given arguments
* @param paramTypes find method with compatible parameters
* @return the accessible method
*/
public static Method getMatchingAccessibleMethod(Class clazz, String methodName, Object[] args,
Class[] paramTypes) {
MethodDescriptor md = new MethodDescriptor(clazz, methodName, paramTypes, false);
// Check the cache first
Method[] result = cache.get(md);
if (result != null) {
return (result.length > 0 ? result[0] : null);
}
// see if we can find the method directly
// most of the time this works and it's much faster
try {
Method method = clazz.getMethod(methodName, paramTypes);
cache.put(md, new Method[] { method });
return method;
} catch (NoSuchMethodException e) {
// ignore
}
// search through all methods
int paramSize = paramTypes.length;
Method bestMatch = null;
Method[] methods = clazz.getMethods();
float bestMatchWeight = Float.MAX_VALUE;
float myWeight;
for (Method method : methods) {
if (method.getName().equals(methodName)) {
// compare parameters
if (method.getParameterCount() == paramSize) {
Class[] methodsParams = method.getParameterTypes();
boolean paramMatch = true;
for (int n = 0; n < methodsParams.length; n++) {
if (args != null) {
if (!TypeUtils.isAssignableValue(methodsParams[n], args[n])) {
paramMatch = false;
break;
}
} else {
if (!TypeUtils.isAssignable(methodsParams[n], paramTypes[n])) {
paramMatch = false;
break;
}
}
}
if (paramMatch) {
if (args != null) {
myWeight = ReflectionUtils.getTypeDifferenceWeight(methodsParams, args);
} else {
myWeight = ReflectionUtils.getTypeDifferenceWeight(methodsParams, paramTypes);
}
if (myWeight < bestMatchWeight) {
bestMatch = method;
bestMatchWeight = myWeight;
}
}
}
}
}
if (bestMatch != null) {
cache.put(md, new Method[] { bestMatch });
} else {
cache.put(md, NO_METHODS);
}
return bestMatch;
}
/**
*
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 slightly undeterminstic since it loops
* through methods names and return the first matching method.
*
* This method can match primitive parameter by passing in wrapper classes.
* For example, a {@code Boolean} will match a primitive {@code boolean}
* parameter.
*
* @param clazz find method in this class
* @param methodName find method with this name
* @param paramTypes find method with compatible parameters
* @return the accessible method
*/
public static Method getMatchingAccessibleMethod(Class clazz, String methodName, Class[] paramTypes) {
return getMatchingAccessibleMethod(clazz, methodName, null, paramTypes);
}
/**
* Clear the method cache.
* @return the number of cached methods cleared
*/
public static synchronized int clearCache() {
int size = cache.size();
cache.clear();
return size;
}
/**
* Represents the key to looking up a Method by reflection.
*/
private static class MethodDescriptor {
private Class cls;
private String methodName;
private Class[] paramTypes;
private boolean exact;
private volatile int hashCode;
/**
* The sole constructor.
*
* @param cls the class to reflect, must not be null
* @param methodName the method name to obtain
* @param paramTypes the array of classes representing the parameter types
* @param exact whether the match has to be exact
*/
private MethodDescriptor(Class cls, String methodName, Class[] paramTypes, boolean exact) {
if (cls == null) {
throw new IllegalArgumentException("cls must not be null");
}
if (methodName == null) {
throw new IllegalArgumentException("methodName must not be null");
}
this.cls = cls;
this.methodName = methodName;
this.paramTypes = (paramTypes != null ? paramTypes : EMPTY_CLASS_PARAMETERS);
this.exact = exact;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
MethodDescriptor md = (MethodDescriptor)obj;
return (
exact == md.exact &&
methodName.equals(md.methodName) &&
cls.equals(md.cls) &&
Arrays.equals(paramTypes, md.paramTypes)
);
}
@Override
public int hashCode() {
final int prime = 31;
int result = hashCode;
if (result == 0) {
result = 11;
result = prime * result + cls.hashCode();
result = prime * result + methodName.hashCode();
result = prime * result + Arrays.hashCode(paramTypes);
result = prime * result + (exact ? 1 : 0);
hashCode = result;
}
return result;
}
}
}