Java example source code file (MethodUtils.java)
The MethodUtils.java Java example source code/*
* 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.annotation.Annotation;
import java.lang.reflect.Array;
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.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
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;
/**
* <p>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.
* </p>
*
* <h3>Known Limitations
* <h4>Accessing Public Methods In A Default Access Superclass
* <p>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.</p>
*
* <p>{@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.</p>
*
* @since 2.5
*/
public class MethodUtils {
/**
* <p>{@link MethodUtils} instances should NOT be constructed in standard programming.
* Instead, the class should be used as
* {@code MethodUtils.getAccessibleMethod(method)}.</p>
*
* <p>This constructor is {@code public} to permit tools that require a JavaBean
* instance to operate.</p>
*/
public MethodUtils() {
super();
}
/**
* <p>Invokes a named method without parameters.
*
* <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* <p>This is a convenient wrapper for
* {@link #invokeMethod(Object object,String methodName, Object[] args, Class[] parameterTypes)}.
* </p>
*
* @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 via reflection
*
* @since 3.4
*/
public static Object invokeMethod(final Object object, final String methodName) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
return invokeMethod(object, methodName, ArrayUtils.EMPTY_OBJECT_ARRAY, null);
}
/**
* <p>Invokes a named method without parameters.
*
* <p>This is a convenient wrapper for
* {@link #invokeMethod(Object object,boolean forceAccess,String methodName, Object[] args, Class[] parameterTypes)}.
* </p>
*
* @param object invoke method on this object
* @param forceAccess force access to invoke method even if it's not accessible
* @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
*
* @since 3.5
*/
public static Object invokeMethod(final Object object, final boolean forceAccess, final String methodName)
throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
return invokeMethod(object, forceAccess, methodName, ArrayUtils.EMPTY_OBJECT_ARRAY, null);
}
/**
* <p>Invokes a named method whose parameter type matches the object type.
*
* <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* <p>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.</p>
*
* <p>This is a convenient wrapper for
* {@link #invokeMethod(Object object,String methodName, Object[] args, Class[] parameterTypes)}.
* </p>
*
* @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);
}
/**
* <p>Invokes a named method whose parameter type matches the object type.
*
* <p>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.</p>
*
* <p>This is a convenient wrapper for
* {@link #invokeMethod(Object object,boolean forceAccess,String methodName, Object[] args, Class[] parameterTypes)}.
* </p>
*
* @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
*
* @since 3.5
*/
public static Object invokeMethod(final Object object, final boolean forceAccess, final String methodName,
Object... args) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
args = ArrayUtils.nullToEmpty(args);
final Class<?>[] parameterTypes = ClassUtils.toClass(args);
return invokeMethod(object, forceAccess, methodName, args, parameterTypes);
}
/**
* <p>Invokes a named method whose parameter type matches the object type.
*
* <p>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.</p>
*
* @param object invoke method on this object
* @param forceAccess force access to invoke method even if it's not accessible
* @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 boolean forceAccess, final String methodName,
Object[] args, Class<?>[] parameterTypes)
throws NoSuchMethodException, IllegalAccessException,
InvocationTargetException {
parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
args = ArrayUtils.nullToEmpty(args);
final String messagePrefix;
Method method = null;
boolean isOriginallyAccessible = false;
Object result = null;
try {
if (forceAccess) {
messagePrefix = "No such method: ";
method = getMatchingMethod(object.getClass(),
methodName, parameterTypes);
if (method != null) {
isOriginallyAccessible = method.isAccessible();
if (!isOriginallyAccessible) {
method.setAccessible(true);
}
}
} else {
messagePrefix = "No such accessible method: ";
method = getMatchingAccessibleMethod(object.getClass(),
methodName, parameterTypes);
}
if (method == null) {
throw new NoSuchMethodException(messagePrefix
+ methodName + "() on object: "
+ object.getClass().getName());
}
args = toVarArgs(method, args);
result = method.invoke(object, args);
}
finally {
if (method != null && forceAccess && method.isAccessible() != isOriginallyAccessible) {
method.setAccessible(isOriginallyAccessible);
}
}
return result;
}
/**
* <p>Invokes a named method whose parameter type matches the object type.
*
* <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* <p>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.</p>
*
* @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 {
return invokeMethod(object, false, methodName, args, parameterTypes);
}
/**
* <p>Invokes a method whose parameter types match exactly the object
* types.</p>
*
* <p>This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod}(Class,String,Class[])}.</p>
*
* @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
* via reflection
*
* @since 3.4
*/
public static Object invokeExactMethod(final Object object, final String methodName) throws NoSuchMethodException,
IllegalAccessException, InvocationTargetException {
return invokeExactMethod(object, methodName, ArrayUtils.EMPTY_OBJECT_ARRAY, null);
}
/**
* <p>Invokes a method with no parameters.
*
* <p>This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod}(Class,String,Class[])}.</p>
*
* @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(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);
}
/**
* <p>Invokes a method whose parameter types match exactly the parameter
* types given.</p>
*
* <p>This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod(Class,String,Class[])}.</p>
*
* @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);
}
/**
* <p>Invokes a {@code static} method whose parameter types match exactly the parameter
* types given.</p>
*
* <p>This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod(Class, String, Class[])}.</p>
*
* @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);
}
/**
* <p>Invokes a named {@code static} method whose parameter type matches the object type.
*
* <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* <p>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.</p>
*
* <p>This is a convenient wrapper for
* {@link #invokeStaticMethod(Class, String, Object[], Class[])}.
* </p>
*
* @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);
}
/**
* <p>Invokes a named {@code static} method whose parameter type matches the object type.
*
* <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.
*
* <p>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.</p>
*
*
* @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());
}
args = toVarArgs(method, args);
return method.invoke(null, args);
}
private static Object[] toVarArgs(Method method, Object[] args) {
if (method.isVarArgs()) {
Class<?>[] methodParameterTypes = method.getParameterTypes();
args = getVarArgs(args, methodParameterTypes);
}
return args;
}
/**
* <p>Given an arguments array passed to a varargs method, return an array of arguments in the canonical form,
* i.e. an array with the declared number of parameters, and whose last parameter is an array of the varargs type.
* </p>
*
* @param args the array of arguments passed to the varags method
* @param methodParameterTypes the declared array of method parameter types
* @return an array of the variadic arguments passed to the method
* @since 3.5
*/
static Object[] getVarArgs(Object[] args, Class<?>[] methodParameterTypes) {
if (args.length == methodParameterTypes.length
&& args[args.length - 1].getClass().equals(methodParameterTypes[methodParameterTypes.length - 1])) {
// The args array is already in the canonical form for the method.
return args;
}
// Construct a new array matching the method's declared parameter types.
Object[] newArgs = new Object[methodParameterTypes.length];
// Copy the normal (non-varargs) parameters
System.arraycopy(args, 0, newArgs, 0, methodParameterTypes.length - 1);
// Construct a new array for the variadic parameters
Class<?> varArgComponentType = methodParameterTypes[methodParameterTypes.length - 1].getComponentType();
int varArgLength = args.length - methodParameterTypes.length + 1;
Object varArgsArray = Array.newInstance(ClassUtils.primitiveToWrapper(varArgComponentType), varArgLength);
// Copy the variadic arguments into the varargs array.
System.arraycopy(args, methodParameterTypes.length - 1, varArgsArray, 0, varArgLength);
if(varArgComponentType.isPrimitive()) {
// unbox from wrapper type to primitive type
varArgsArray = ArrayUtils.toPrimitive(varArgsArray);
}
// Store the varargs array in the last position of the array to return
newArgs[methodParameterTypes.length - 1] = varArgsArray;
// Return the canonical varargs array.
return newArgs;
}
/**
* <p>Invokes a {@code static} method whose parameter types match exactly the object
* types.</p>
*
* <p>This uses reflection to invoke the method obtained from a call to
* {@link #getAccessibleMethod(Class, String, Class[])}.</p>
*
* @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);
}
/**
* <p>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)}.</p>
*
* @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;
}
}
/**
* <p>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}.</p>
*
* @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;
}
/**
* <p>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}.</p>
*
* @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;
}
/**
* <p>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}.</p>
*
* <p>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.</p>
*
* @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
final Method method = getAccessibleMethodFromInterfaceNest(interfaces[i],
methodName, parameterTypes);
if (method != null) {
return method;
}
}
}
return null;
}
/**
* <p>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.</p>
*
* <p>This method is used by
* {@link
* #invokeMethod(Object object, String methodName, Object[] args, Class[] parameterTypes)}.
* </p>
*
* <p>This method can match primitive parameter by passing in wrapper classes.
* For example, a {@code Boolean} will match a primitive {@code boolean}
* parameter.
* </p>
*
* @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) &&
MemberUtils.isMatchingMethod(method, parameterTypes)) {
// get accessible version of method
final Method accessibleMethod = getAccessibleMethod(method);
if (accessibleMethod != null && (bestMatch == null || MemberUtils.compareMethodFit(
accessibleMethod,
bestMatch,
parameterTypes) < 0)) {
bestMatch = accessibleMethod;
}
}
}
if (bestMatch != null) {
MemberUtils.setAccessibleWorkaround(bestMatch);
}
return bestMatch;
}
/**
* <p>Retrieves a method whether or not it's accessible. If no such method
* can be found, return {@code null}.</p>
* @param cls The class that will be subjected to the method search
* @param methodName The method that we wish to call
* @param parameterTypes Argument class types
* @return The method
*
* @since 3.5
*/
public static Method getMatchingMethod(final Class<?> cls, final String methodName,
final Class<?>... parameterTypes) {
Validate.notNull(cls, "Null class not allowed.");
Validate.notEmpty(methodName, "Null or blank methodName not allowed.");
// Address methods in superclasses
Method[] methodArray = cls.getDeclaredMethods();
List<Class superclassList = ClassUtils.getAllSuperclasses(cls);
for (Class<?> klass: superclassList) {
methodArray = ArrayUtils.addAll(methodArray, klass.getDeclaredMethods());
}
Method inexactMatch = null;
for (Method method: methodArray) {
if (methodName.equals(method.getName()) &&
ArrayUtils.isEquals(parameterTypes, method.getParameterTypes())) {
return method;
} else if (methodName.equals(method.getName()) &&
ClassUtils.isAssignable(parameterTypes, method.getParameterTypes(), true)) {
if (inexactMatch == null) {
inexactMatch = method;
} else if (distance(parameterTypes, method.getParameterTypes())
< distance(parameterTypes, inexactMatch.getParameterTypes())) {
inexactMatch = method;
}
}
}
return inexactMatch;
}
/**
* <p>Returns the aggregate number of inheritance hops between assignable argument class types. Returns -1
* if the arguments aren't assignable. Fills a specific purpose for getMatchingMethod and is not generalized.</p>
* @param classArray
* @param toClassArray
* @return the aggregate number of inheritance hops between assignable argument class types.
*/
private static int distance(Class<?>[] classArray, Class[] toClassArray) {
int answer=0;
if (!ClassUtils.isAssignable(classArray, toClassArray, true)) {
return -1;
}
for (int offset = 0; offset < classArray.length; offset++) {
// Note InheritanceUtils.distance() uses different scoring system.
if (classArray[offset].equals(toClassArray[offset])) {
continue;
} else if (ClassUtils.isAssignable(classArray[offset], toClassArray[offset], true)
&& !ClassUtils.isAssignable(classArray[offset], toClassArray[offset], false)) {
answer++;
} else {
answer = answer+2;
}
}
return answer;
}
/**
* 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<Method> in ascending order from sub- to superclass
* @throws NullPointerException if the specified method is {@code null}
* @since 3.2
*/
public static Set<Method> getOverrideHierarchy(final Method method, final Interfaces interfacesBehavior) {
Validate.notNull(method);
final Set<Method> result = new LinkedHashSet
Other Java examples (source code examples)Here is a short list of links related to this Java MethodUtils.java source code file: |
The search page
Other Java source code examples at this package level
Click here to learn more about this project
