001// Copyright 2009-2013 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.services.assets.CompressionAnalyzer;
018
019/**
020 * Used to determine if the client supports GZip compression of the response.
021 *
022 * @see CompressionAnalyzer
023 * @see org.apache.tapestry5.SymbolConstants#GZIP_COMPRESSION_ENABLED
024 * @since 5.1.0.0
025 */
026public interface ResponseCompressionAnalyzer
027{
028    /**
029     * Checks the Accept-Encoding request header for a "gzip" token. Ensures that the protocol is not "HTTP/1.0", which
030     * does not correctly support GZip encoding (in older Internet Explorer browsers).
031     *
032     * @return true if gzip is supported by client
033     */
034    boolean isGZipSupported();
035
036    /**
037     * Uses {@link CompressionAnalyzer} to determine if the content is compressable, but only if the request
038     * indicates the client supports compression.
039     *
040     * @param contentType
041     * @return true if the content can be compressed for the current request
042     * @since 5.4
043     */
044    boolean isGZipEnabled(String contentType);
045}