001// Copyright 2005 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.tapestry.asset;
016
017import java.util.Locale;
018
019import org.apache.hivemind.Location;
020import org.apache.hivemind.Resource;
021import org.apache.tapestry.IAsset;
022
023/**
024 * Used to create an {@link org.apache.tapestry.IAsset} instance for a particular asset path. The
025 * path may have a prefix that indicates its type, or it may be relative to some existing resource.
026 * 
027 * @author Howard M. Lewis Ship
028 * @since 4.0
029 */
030public interface AssetSource
031{
032    /**
033     * Finds an asset relative to some existing resource (typically, a page, component or library
034     * specification).
035     * 
036     * @param base
037     *            the base resource used for resolving the asset
038     * @param path
039     *            the path relative to the base resource; alternately, the path may include a prefix
040     *            that defines a domain (such as "classpath:" or "context:") in which case the base
041     *            resource is ignored and the resource resolved within that domain
042     * @param locale
043     *            used to find a localized version of the asset, may be null to indicate no
044     *            localization
045     * @param location
046     *            used to report errors (such as missing resources)
047     * @return the asset, possibly localized
048     * @throws org.apache.hivemind.ApplicationRuntimeException
049     *             if the asset does not exist
050     */
051    public IAsset findAsset(Resource base, String path, Locale locale, Location location);
052}