001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.services;
014
015import org.apache.tapestry5.ContentType;
016import org.apache.tapestry5.services.assets.CompressionAnalyzer;
017
018/**
019 * Used to determine if the client supports GZip compression of the response.
020 *
021 * @see CompressionAnalyzer
022 * @see org.apache.tapestry5.SymbolConstants#GZIP_COMPRESSION_ENABLED
023 * @since 5.1.0.0
024 */
025public interface ResponseCompressionAnalyzer
026{
027    /**
028     * Checks the Accept-Encoding request header for a "gzip" token. Ensures that the protocol is not "HTTP/1.0", which
029     * does not correctly support GZip encoding (in older Internet Explorer browsers).
030     *
031     * @return true if gzip is supported by client
032     */
033    boolean isGZipSupported();
034
035    /**
036     * Uses {@link CompressionAnalyzer} to determine if the content is compressable, but only if the request
037     * indicates the client supports compression.
038     *
039     * @param contentType
040     * @return true if the content can be compressed for the current request
041     * @since 5.4
042     */
043    boolean isGZipEnabled(ContentType contentType);
044}