001// Copyright 2006, 2007, 2008, 2013 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.services; 016 017import org.apache.tapestry5.Asset; 018import org.apache.tapestry5.ioc.Resource; 019 020/** 021 * Used by {@link AssetSource} to create new {@link Asset}s as needed. 022 * <p/> 023 * Starting in Tapestry 5.4, the built-in implementations of this interface (for context assets, and for classpath assets) 024 * were changed so that when underlying resources changed, the client URLs for Assets are discarded; this is necessitated by two factors: 025 * <p/>1) the {@linkplain org.apache.tapestry5.Asset#toClientURL() client URL} 026 * for an Asset now includes a checksum based on the content of the underlying resource, so a change to resource content 027 * (during development) results in a change to the URL. 028 * <p/>2) {@link org.apache.tapestry5.services.javascript.JavaScriptStack} (especially the {@link org.apache.tapestry5.services.javascript.ExtensibleJavaScriptStack} implementation) 029 * made no provision for rebuilding the Assets post-construction, and there is no backwards compatible way to 030 * introduce this concept (and JavaScriptStacks are something many applications and third-party libraries make use of). 031 * <p/>So, starting in Tapestry 5.4, the implementations of {@link Asset} should be 032 * 033 * @see org.apache.tapestry5.services.AssetSource 034 */ 035public interface AssetFactory 036{ 037 /** 038 * Returns the Resource representing the root folder of the domain this factory is responsible for. 039 */ 040 Resource getRootResource(); 041 042 /** 043 * Creates an instance of an asset. Starting with 5.1.0.0, it is preferred (but not required) that the factory 044 * return an instance of {@link org.apache.tapestry5.Asset2}. 045 * 046 * @param resource 047 * a resource within this factories domain (derived from the {@linkplain #getRootResource() root 048 * resource}) 049 * @return an Asset for the resource 050 */ 051 Asset createAsset(Resource resource); 052}