/*
 * 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.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.ArrayList;
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</h3>
 * <h4>Accessing Public Methods In A Default Access Superclass</h4>
 * <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
 * @version $Id$
 */
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>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</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
     * @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 whose parameter type matches the object type.</p>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <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>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <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 {
        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);
    }

    /**
     * <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>
     *
     * <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>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <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>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <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());
        }
        return method.invoke(null, args);
    }

    /**
     * <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) && 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&lt;Method&gt; 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<Method>();
        result.add(method);

        final Class<?>[] parameterTypes = method.getParameterTypes();

        final Class<?> declaringClass = method.getDeclaringClass();

        final Iterator<Class<?>> 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<TypeVariable<?>, 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;
    }

    /**
     * Gets all methods of the given class that are annotated with the given annotation.
     * @param cls
     *            the {@link Class} to query
     * @param annotationCls
     *            the {@link java.lang.annotation.Annotation} that must be present on a method to be matched
     * @return an array of Methods (possibly empty).
     * @throws IllegalArgumentException
     *            if the class or annotation are {@code null}
     * @since 3.4
     */
    public static Method[] getMethodsWithAnnotation(final Class<?> cls, final Class<? extends Annotation> annotationCls) {
        final List<Method> annotatedMethodsList = getMethodsListWithAnnotation(cls, annotationCls);
        return annotatedMethodsList.toArray(new Method[annotatedMethodsList.size()]);
    }

    /**
     * Gets all methods of the given class that are annotated with the given annotation.
     * @param cls
     *            the {@link Class} to query
     * @param annotationCls
     *            the {@link Annotation} that must be present on a method to be matched
     * @return a list of Methods (possibly empty).
     * @throws IllegalArgumentException
     *            if the class or annotation are {@code null}
     * @since 3.4
     */
    public static List<Method> getMethodsListWithAnnotation(final Class<?> cls, final Class<? extends Annotation> annotationCls) {
        Validate.isTrue(cls != null, "The class must not be null");
        Validate.isTrue(annotationCls != null, "The annotation class must not be null");
        final Method[] allMethods = cls.getMethods();
        final List<Method> annotatedMethods = new ArrayList<Method>();
        for (final Method method : allMethods) {
            if (method.getAnnotation(annotationCls) != null) {
                annotatedMethods.add(method);
            }
        }
        return annotatedMethods;
    }

}
