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    
021    /**
022     * Understands the return type of the method to invoke.
023     * <p>
024     * The following is an example of proper usage of this class:
025     * <pre>
026     *   // Equivalent to call 'person.setName("Luke")'
027     *   {@link org.fest.reflect.core.Reflection#method(String) method}("setName").{@link MethodName#withParameterTypes(Class...) withParameterTypes}(String.class)
028     *                    .{@link MethodParameterTypes#in(Object) in}(person)
029     *                    .{@link Invoker#invoke(Object...) invoke}("Luke");
030     *
031     *   // Equivalent to call 'person.concentrate()'
032     *   {@link org.fest.reflect.core.Reflection#method(String) method}("concentrate").{@link MethodName#in(Object) in}(person).{@link Invoker#invoke(Object...) invoke}();
033     *
034     *   // Equivalent to call 'person.getName()'
035     *   String name = {@link org.fest.reflect.core.Reflection#method(String) method}("getName").{@link MethodName#withReturnType(Class) withReturnType}(String.class)
036     *                                  .{@link MethodReturnType#in(Object) in}(person)
037     *                                  .{@link Invoker#invoke(Object...) invoke}();
038     * </pre>
039     * </p>
040     *
041     * @param <T> the generic type of the method's return type.
042     *
043     * @author Yvonne Wang
044     * @author Alex Ruiz
045     */
046    public class MethodReturnType<T> {
047    
048      static <T> MethodReturnType<T> newReturnType(String name, Class<T> type) {
049        if (type == null) throw new NullPointerException("The return type of the method to access should not be null");
050        return new MethodReturnType<T>(name);
051      }
052    
053      private final String name;
054    
055      private MethodReturnType(String name) {
056        this.name = name;
057      }
058    
059      /**
060       * Creates a new method invoker.
061       * @param target the object containing the method to invoke.
062       * @return the created method invoker.
063       * @throws NullPointerException if the given target is <code>null</code>.
064       */
065      public Invoker<T> in(Object target) {
066        return newInvoker(name, target);
067      }
068    
069      /**
070       * Specifies the parameter types of the method to invoke. This method call is optional if the method to invoke does
071       * not take arguments.
072       * @param parameterTypes the parameter types of the method to invoke.
073       * @return the created parameter types holder.
074       * @throws NullPointerException if the array of parameter types is <code>null</code>.
075       */
076      public MethodParameterTypes<T> withParameterTypes(Class<?>... parameterTypes) {
077        return newParameterTypes(name, parameterTypes);
078      }
079    }