001// Copyright 2006, 2007, 2008, 2009, 2011 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// 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 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5.internal.services; 016 017import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration; 018import org.apache.tapestry5.ioc.services.ClassFactory; 019import org.apache.tapestry5.ioc.services.PlasticProxyFactory; 020import org.apache.tapestry5.services.transform.ControlledPackageType; 021 022/** 023 * Creates {@link org.apache.tapestry5.internal.services.Instantiator}s for components, based on component class name. 024 * This will involve transforming the component's class before it is loaded. 025 * <p/> 026 * In addition, a source acts as an event hub for {@link org.apache.tapestry5.services.InvalidationListener}s, so that 027 * any information derived from loaded classes can be discarded and rebuilt when classes change. 028 * <p/> 029 * The strategy used is that when <em>any</em> class (in a controlled package) changes, the entire class loader is 030 * discarded, along with any instances derived from those classes. A new class loader is created, and then invalidation 031 * events are fired to listeners. 032 * <p/> 033 * Starting in Tapestry 5.3, the packages that are loaded are controlled by a configuration that maps package names to 034 * {@link ControlledPackageType}s. 035 */ 036@UsesMappedConfiguration(key = String.class, value = ControlledPackageType.class) 037public interface ComponentInstantiatorSource 038{ 039 040 /** 041 * Given the name of a component class, provides an instantiator for that component. Instantiators are cached, so 042 * repeated calls to this method with the same class name will return the same instance; however, callers should 043 * also be aware that the instantiators may lose validity after an invalidation (caused by changes to external Java 044 * class files). 045 * 046 * @param classname FQCN to find (and perhaps transform and load) 047 * @return an object which can instantiate an instance of the component 048 */ 049 Instantiator getInstantiator(String classname); 050 051 /** 052 * Checks to see if a fully qualified class name exists. This method appears to exist only for testing. 053 * 054 * @param className name of class to check 055 * @return true if the class exists (there's a ".class" file), false otherwise 056 */ 057 boolean exists(String className); 058 059 /** 060 * Returns a class factory that can be used to generate additional classes around enhanced classes, or create 061 * subclasses of enhanced classes. 062 * 063 * @deprecated Deprecated in 5.3, to be removed in 5.4 064 */ 065 ClassFactory getClassFactory(); 066 067 /** 068 * Returns a proxy factory that can be used to generate additional classes around enhanced classes, or create 069 * subclasses of enhanced classes. 070 * 071 * @since 5.3 072 */ 073 PlasticProxyFactory getProxyFactory(); 074 075 /** 076 * Forces invalidation logic, as if a component class on the disk had changed, forcing a reload 077 * of all pages and components. 078 * 079 * @since 5.3 080 */ 081 void forceComponentInvalidation(); 082}