| /* |
| * Copyright (c) 2007, Rickard Öberg. All Rights Reserved. |
| * |
| * 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 org.qi4j.api.common; |
| |
| import java.lang.reflect.Method; |
| |
| /** |
| * Implementations of this interface can be specified in the @AppliesTo. |
| * <p> |
| * AppliesTo filters are one of the driving technologies in Zest. They allow you to apply fragments (Mixins, |
| * Concerns, SideEffects), often generic ones, depending on the context that they are evaluated under. This |
| * mechanism is heavily used internally in Zest to achieve many other features. |
| * </p> |
| * <p> |
| * The starting point is the basic use of AppliesToFilter, where the @AppliesTo annotation is given an |
| * AppliesToFilter implementation as an argument, for instance at a Mixin implementation; |
| * </p> |
| * <pre><code> |
| * @AppliesTo( MyAppliesToFilter.class ) |
| * public class SomeMixin |
| * implements InvocationHandler |
| * { |
| * |
| * } |
| * |
| * public class MyAppliesToFilter |
| * implements AppliesToFilter |
| * { |
| * public boolean appliesTo( Method method, Class<?> mixin, Class<?> compositeType, Class<?> fragmentClass ) |
| * { |
| * return method.getName().startsWith( "my" ); |
| * } |
| * } |
| * </code></pre> |
| * <p> |
| * In the case above, the generic mixin will only be applied to the methods that that is defined by the |
| * AppliesToFilter. This is the primary way to define limits on the application of generic fragments, since |
| * especially mixins are rarely applied to all methods. |
| * </p> |
| */ |
| public interface AppliesToFilter |
| { |
| /** |
| * This is an internal AppliesToFilter which is assigned if no other AppliesToFilters are found for a given |
| * fragment. |
| * <p> |
| * There is no reason for user code to use this AppliesToFilter directly, and should be perceived as an |
| * internal class in Zest. |
| * </p> |
| */ |
| AppliesToFilter ALWAYS = new AppliesToFilter() |
| { |
| @Override |
| public boolean appliesTo( Method method, Class<?> mixin, Class<?> compositeType, Class<?> fragmentClass ) |
| { |
| return true; |
| } |
| }; |
| |
| /** |
| * Check if the Fragment should be applied or not. Will be call when applied to Mixins, Concerns, SideEffects. |
| * |
| * @param method method that is invoked |
| * @param mixin mixin implementation for the method |
| * @param compositeType composite type |
| * @param fragmentClass fragment that is being applies |
| * |
| * @return true if the filter passes, otherwise false |
| */ |
| boolean appliesTo( Method method, Class<?> mixin, Class<?> compositeType, Class<?> fragmentClass ); |
| } |