    001    // Copyright 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
    015    package org.apache.tapestry5.services.assets;
    016
    017    import org.apache.tapestry5.ioc.Resource;
    018    import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
    019
    020    import java.io.IOException;
    021
    022    /**
    023     * Converts {@link Resource}s into {@link StreamableResource}s, and may be responsible for
    024     * {@linkplain ResourceTransformer transforming} resources based on file extension. In addition,
    025     * service decorators added to the service may provide additional processing (compression, minimization, and caching).
    026     *
    027     * @since 5.3
    028     */
    029    @UsesMappedConfiguration(ResourceTransformer.class)
    030    public interface StreamableResourceSource
    031    {
    032        /**
    033         * Converts a Resource (which must be non-null and exist) into a streamable resource, along with
    034         * some additional optional behaviors.
    035         *
    036         * @param baseResource the resource to convert
    037         * @param processing   defines additional processing after the resource has been read and possibly transformed
    038         * @param dependencies Passed to any {@link ResourceTransformer} to track additional dependencies of the base resource
    039         * @return the contents of the Resource, possibly transformed, in a streamable format.
    040         * @throws IOException if the resource does not exist or a URL for the content is not available
    041         */
    042        StreamableResource getStreamableResource(Resource baseResource, StreamableResourceProcessing processing, ResourceDependencies dependencies)
    043                throws IOException;
    044    }