001 /*
002 * Created on Aug 17, 2007
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 *
014 * Copyright @2007-2009 the original author or authors.
015 */
016 package org.fest.reflect.method;
017
018 import static org.fest.reflect.method.Invoker.newInvoker;
019 import static org.fest.reflect.method.MethodParameterTypes.newParameterTypes;
020 import static org.fest.reflect.method.MethodReturnType.newReturnType;
021 import static org.fest.reflect.method.MethodReturnTypeRef.newReturnTypeRef;
022 import static org.fest.util.Strings.isEmpty;
023
024 import org.fest.reflect.reference.TypeRef;
025
026
027
028 /**
029 * Understands the name of a method to invoke using Java Reflection.
030 * <p>
031 * The following is an example of proper usage of this class:
032 * <pre>
033 * // Equivalent to call 'person.setName("Luke")'
034 * {@link org.fest.reflect.core.Reflection#method(String) method}("setName").{@link MethodName#withParameterTypes(Class...) withParameterTypes}(String.class)
035 * .{@link MethodParameterTypes#in(Object) in}(person)
036 * .{@link Invoker#invoke(Object...) invoke}("Luke");
037 *
038 * // Equivalent to call 'person.concentrate()'
039 * {@link org.fest.reflect.core.Reflection#method(String) method}("concentrate").{@link MethodName#in(Object) in}(person).{@link Invoker#invoke(Object...) invoke}();
040 *
041 * // Equivalent to call 'person.getName()'
042 * String name = {@link org.fest.reflect.core.Reflection#method(String) method}("getName").{@link MethodName#withReturnType(Class) withReturnType}(String.class)
043 * .{@link MethodReturnType#in(Object) in}(person)
044 * .{@link Invoker#invoke(Object...) invoke}();
045 *
046 * // Equivalent to call 'jedi.getPowers()'
047 * List<String> powers = {@link org.fest.reflect.core.Reflection#method(String) method}("getPowers").{@link MethodName#withReturnType(TypeRef) withReturnType}(new {@link TypeRef TypeRef}<List<String>>() {})
048 * .{@link MethodReturnTypeRef#in(Object) in}(person)
049 * .{@link Invoker#invoke(Object...) invoke}();
050 * </pre>
051 * </p>
052 *
053 * @author Yvonne Wang
054 * @author Alex Ruiz
055 */
056 public final class MethodName {
057
058 /**
059 * Creates a new <code>{@link MethodName}</code>: the starting point of the fluent interface for accessing methods
060 * using Java Reflection.
061 * @param name the name of the method to invoke using Java Reflection.
062 * @return the created <code>MethodName</code>.
063 * @throws NullPointerException if the given name is <code>null</code>.
064 * @throws IllegalArgumentException if the given name is empty.
065 */
066 public static MethodName startMethodAccess(String name) {
067 validateIsNotNullOrEmpty(name);
068 return new MethodName(name);
069 }
070
071 private static void validateIsNotNullOrEmpty(String name) {
072 if (name == null)
073 throw new NullPointerException("The name of the method to access should not be null");
074 if (isEmpty(name))
075 throw new IllegalArgumentException("The name of the method to access should not be empty");
076 }
077
078 private final String name;
079
080 private MethodName(String name) {
081 this.name = name;
082 }
083
084 /**
085 * Specifies the return type of the method to invoke. This method call is optional if the return type of the method to
086 * invoke is <code>void</code>.
087 * @param <T> the generic type of the method's return type.
088 * @param type the return type of the method to invoke.
089 * @return the created return type holder.
090 * @throws NullPointerException if the given type is <code>null</code>.
091 */
092 public <T> MethodReturnType<T> withReturnType(Class<T> type) {
093 return newReturnType(name, type);
094 }
095
096 /**
097 * Specifies the return type reference of the method to invoke. This method call is optional if the return type of the
098 * method to invoke is <code>void</code>.
099 * @param <T> the generic type of the method's return type.
100 * @param type the return type reference of the method to invoke.
101 * @return the created return type holder.
102 * @throws NullPointerException if the given type reference is <code>null</code>.
103 * @since 1.1
104 */
105 public <T> MethodReturnTypeRef<T> withReturnType(TypeRef<T> type) {
106 return newReturnTypeRef(name, type);
107 }
108
109 /**
110 * Specifies the parameter types of the method to invoke. This method call is optional if the method to invoke does
111 * not take arguments.
112 * @param parameterTypes the parameter types of the method to invoke.
113 * @return the created parameter types holder.
114 * @throws NullPointerException if the array of parameter types is <code>null</code>.
115 */
116 public MethodParameterTypes<Void> withParameterTypes(Class<?>... parameterTypes) {
117 return newParameterTypes(name, parameterTypes);
118 }
119
120 /**
121 * Creates a new invoker for a method that takes no parameters and return value <code>void</code>.
122 * @param target the object containing the method to invoke.
123 * @return the created method invoker.
124 * @throws NullPointerException if the given target is <code>null</code>.
125 */
126 public Invoker<Void> in(Object target) {
127 return newInvoker(name, target);
128 }
129 }