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/*
 * Copyright (C) 2012 The Guava Authors
 *
 * 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 jersey.repackaged.com.google.common.reflect;

import static jersey.repackaged.com.google.common.base.Preconditions.checkNotNull;

import jersey.repackaged.com.google.common.annotations.Beta;
import jersey.repackaged.com.google.common.collect.ImmutableList;

import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
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 javax.annotation.Nullable;

/**
 * Wrapper around either a {@link Method} or a {@link Constructor}.
 * Convenience API is provided to make common reflective operation easier to deal with,
 * such as {@link #isPublic}, {@link #getParameters} etc.
 *
 * 

In addition to convenience methods, {@link TypeToken#method} and {@link * TypeToken#constructor} will resolve the type parameters of the method or constructor in the * context of the owner type, which may be a subtype of the declaring class. For example: *

   {@code
 *
 *   Method getMethod = List.class.getMethod("get", int.class);
 *   Invokable, ?> invokable = new TypeToken>() {}.method(getMethod);
 *   assertEquals(TypeToken.of(String.class), invokable.getReturnType()); // Not Object.class!
 *   assertEquals(new TypeToken>() {}, invokable.getOwnerType());}
* * @param the type that owns this method or constructor. * @param the return type of (or supertype thereof) the method or the declaring type of the * constructor. * @author Ben Yu * @since 14.0 */ @Beta public abstract class Invokable extends Element implements GenericDeclaration { Invokable(M member) { super(member); } /** Returns {@link Invokable} of {@code method}. */ public static Invokable from(Method method) { return new MethodInvokable(method); } /** Returns {@link Invokable} of {@code constructor}. */ public static Invokable from(Constructor constructor) { return new ConstructorInvokable(constructor); } /** * Returns {@code true} if this is an overridable method. Constructors, private, static or final * methods, or methods declared by final classes are not overridable. */ public abstract boolean isOverridable(); /** Returns {@code true} if this was declared to take a variable number of arguments. */ public abstract boolean isVarArgs(); /** * Invokes with {@code receiver} as 'this' and {@code args} passed to the underlying method * and returns the return value; or calls the underlying constructor with {@code args} and returns * the constructed instance. * * @throws IllegalAccessException if this {@code Constructor} object enforces Java language * access control and the underlying method or constructor is inaccessible. * @throws IllegalArgumentException if the number of actual and formal parameters differ; * if an unwrapping conversion for primitive arguments fails; or if, after possible * unwrapping, a parameter value cannot be converted to the corresponding formal * parameter type by a method invocation conversion. * @throws InvocationTargetException if the underlying method or constructor throws an exception. */ // All subclasses are owned by us and we'll make sure to get the R type right. @SuppressWarnings("unchecked") public final R invoke(@Nullable T receiver, Object... args) throws InvocationTargetException, IllegalAccessException { return (R) invokeInternal(receiver, checkNotNull(args)); } /** Returns the return type of this {@code Invokable}. */ // All subclasses are owned by us and we'll make sure to get the R type right. @SuppressWarnings("unchecked") public final TypeToken getReturnType() { return (TypeToken) TypeToken.of(getGenericReturnType()); } /** * Returns all declared parameters of this {@code Invokable}. Note that if this is a constructor * of a non-static inner class, unlike {@link Constructor#getParameterTypes}, the hidden * {@code this} parameter of the enclosing class is excluded from the returned parameters. */ public final ImmutableList getParameters() { Type[] parameterTypes = getGenericParameterTypes(); Annotation[][] annotations = getParameterAnnotations(); ImmutableList.Builder builder = ImmutableList.builder(); for (int i = 0; i < parameterTypes.length; i++) { builder.add(new Parameter( this, i, TypeToken.of(parameterTypes[i]), annotations[i])); } return builder.build(); } /** Returns all declared exception types of this {@code Invokable}. */ public final ImmutableList> getExceptionTypes() { ImmutableList.Builder> builder = ImmutableList.builder(); for (Type type : getGenericExceptionTypes()) { // getGenericExceptionTypes() will never return a type that's not exception @SuppressWarnings("unchecked") TypeToken exceptionType = (TypeToken) TypeToken.of(type); builder.add(exceptionType); } return builder.build(); } /** * Explicitly specifies the return type of this {@code Invokable}. For example: *
   {@code
   *   Method factoryMethod = Person.class.getMethod("create");
   *   Invokable factory = Invokable.of(getNameMethod).returning(Person.class);
   * }
*/ public final Invokable returning(Class returnType) { return returning(TypeToken.of(returnType)); } /** Explicitly specifies the return type of this {@code Invokable}. */ public final Invokable returning(TypeToken returnType) { if (!returnType.isAssignableFrom(getReturnType())) { throw new IllegalArgumentException( "Invokable is known to return " + getReturnType() + ", not " + returnType); } @SuppressWarnings("unchecked") // guarded by previous check Invokable specialized = (Invokable) this; return specialized; } @SuppressWarnings("unchecked") // The declaring class is T's raw class, or one of its supertypes. @Override public final Class getDeclaringClass() { return (Class) super.getDeclaringClass(); } /** Returns the type of {@code T}. */ // Overridden in TypeToken#method() and TypeToken#constructor() @SuppressWarnings("unchecked") // The declaring class is T. public TypeToken getOwnerType() { return (TypeToken) TypeToken.of(getDeclaringClass()); } abstract Object invokeInternal(@Nullable Object receiver, Object[] args) throws InvocationTargetException, IllegalAccessException; abstract Type[] getGenericParameterTypes(); /** This should never return a type that's not a subtype of Throwable. */ abstract Type[] getGenericExceptionTypes(); abstract Annotation[][] getParameterAnnotations(); abstract Type getGenericReturnType(); static class MethodInvokable extends Invokable { private final Method method; MethodInvokable(Method method) { super(method); this.method = method; } @Override final Object invokeInternal(@Nullable Object receiver, Object[] args) throws InvocationTargetException, IllegalAccessException { return method.invoke(receiver, args); } @Override Type getGenericReturnType() { return method.getGenericReturnType(); } @Override Type[] getGenericParameterTypes() { return method.getGenericParameterTypes(); } @Override Type[] getGenericExceptionTypes() { return method.getGenericExceptionTypes(); } @Override final Annotation[][] getParameterAnnotations() { return method.getParameterAnnotations(); } @Override public final TypeVariable[] getTypeParameters() { return method.getTypeParameters(); } @Override public final boolean isOverridable() { return !(isFinal() || isPrivate() || isStatic() || Modifier.isFinal(getDeclaringClass().getModifiers())); } @Override public final boolean isVarArgs() { return method.isVarArgs(); } } static class ConstructorInvokable extends Invokable { private final Constructor constructor; ConstructorInvokable(Constructor constructor) { super(constructor); this.constructor = constructor; } @Override final Object invokeInternal(@Nullable Object receiver, Object[] args) throws InvocationTargetException, IllegalAccessException { try { return constructor.newInstance(args); } catch (InstantiationException e) { throw new RuntimeException(constructor + " failed.", e); } } @Override Type getGenericReturnType() { return constructor.getDeclaringClass(); } @Override Type[] getGenericParameterTypes() { Type[] types = constructor.getGenericParameterTypes(); Class declaringClass = constructor.getDeclaringClass(); if (!Modifier.isStatic(declaringClass.getModifiers()) && declaringClass.getEnclosingClass() != null) { if (types.length == constructor.getParameterTypes().length) { // first parameter is the hidden 'this' return Arrays.copyOfRange(types, 1, types.length); } } return types; } @Override Type[] getGenericExceptionTypes() { return constructor.getGenericExceptionTypes(); } @Override final Annotation[][] getParameterAnnotations() { return constructor.getParameterAnnotations(); } @Override public final TypeVariable[] getTypeParameters() { return constructor.getTypeParameters(); } @Override public final boolean isOverridable() { return false; } @Override public final boolean isVarArgs() { return constructor.isVarArgs(); } } }