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.StaticMethodParameterTypes.newParameterTypes;
020    
021    import org.fest.reflect.reference.TypeRef;
022    
023    /**
024     * Understands the return type of the static method to invoke.
025     * <p>
026     * The following is an example of proper usage of this class:
027     * <pre>
028     *   // Equivalent to call 'Jedi.setCommonPower("Jump")'
029     *   {@link org.fest.reflect.core.Reflection#staticMethod(String) staticMethod}("setCommonPower").{@link StaticMethodName#withParameterTypes(Class...) withParameterTypes}(String.class)
030     *                                 .{@link StaticMethodParameterTypes#in(Class) in}(Jedi.class)
031     *                                 .{@link Invoker#invoke(Object...) invoke}("Jump");
032     *
033     *   // Equivalent to call 'Jedi.addPadawan()'
034     *   {@link org.fest.reflect.core.Reflection#staticMethod(String) staticMethod}("addPadawan").{@link StaticMethodName#in(Class) in}(Jedi.class).{@link Invoker#invoke(Object...) invoke}();
035     *
036     *   // Equivalent to call 'Jedi.commonPowerCount()'
037     *   String name = {@link org.fest.reflect.core.Reflection#staticMethod(String) staticMethod}("commonPowerCount").{@link StaticMethodName#withReturnType(Class) withReturnType}(String.class)
038     *                                                 .{@link StaticMethodReturnType#in(Class) in}(Jedi.class)
039     *                                                 .{@link Invoker#invoke(Object...) invoke}();
040     *
041     *   // Equivalent to call 'Jedi.getCommonPowers()'
042     *   List&lt;String&gt; powers = {@link org.fest.reflect.core.Reflection#staticMethod(String) staticMethod}("getCommonPowers").{@link StaticMethodName#withReturnType(TypeRef) withReturnType}(new {@link TypeRef TypeRef}&lt;List&lt;String&gt;&gt;() {})
043     *                                                        .{@link StaticMethodReturnTypeRef#in(Class) in}(Jedi.class)
044     *                                                        .{@link Invoker#invoke(Object...) invoke}();
045     * </pre>
046     * </p>
047     *
048     * @param <T> the generic type of the static method's return type.
049     *
050     * @author Alex Ruiz
051     */
052    public class StaticMethodReturnType<T> {
053    
054      static <T> StaticMethodReturnType<T> newReturnType(String name, Class<T> type) {
055        if (type == null)
056          throw new NullPointerException("The return type of the static method to access should not be null");
057        return new StaticMethodReturnType<T>(name);
058      }
059    
060      private final String name;
061    
062      private StaticMethodReturnType(String name) {
063        this.name = name;
064      }
065    
066      /**
067       * Creates a new method invoker.
068       * @param target the object containing the method to invoke.
069       * @return the created method invoker.
070       * @throws NullPointerException if the given target is <code>null</code>.
071       */
072      public Invoker<T> in(Class<?> target) {
073        return newInvoker(name, target);
074      }
075    
076      /**
077       * Specifies the parameter types of the static method to invoke. This method call is optional if the method to invoke
078       * does not take arguments.
079       * @param parameterTypes the parameter types of the method to invoke.
080       * @return the created parameter types holder.
081       * @throws NullPointerException if the array of parameter types is <code>null</code>.
082       */
083      public StaticMethodParameterTypes<T> withParameterTypes(Class<?>... parameterTypes) {
084        return newParameterTypes(name, parameterTypes);
085      }
086    }