    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.
    014package org.apache.tapestry5.http.services;
    015
    016import javax.servlet.http.HttpServletRequest;
    017
    018import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
    019
    020/**
    021 * Service that converts the body of an HTTP request to a given target class.
    022 * Each implementation, which should be contributed to the {@link HttpRequestBodyConverter} service,
    023 * should check whether it can actually handled that request. If not, it should return <code>null</code>,
    024 * which means trying the next HttpRequestBodyConverter instance.
    025 */
    026@UsesOrderedConfiguration(HttpRequestBodyConverter.class)
    027public interface HttpRequestBodyConverter
    028{
    029
    030    /**
    031     * Converts the body of this request. If this implementation cannot handle this request,
    032     * probably by not handling its content type, it should return <code>null</code>.
    033     * In addition, if the request body is empty, this method should also return
    034     * <code>null</code>.
    035     * @param request an {@linkplain HttpServletRequest}.
    036     * @param type the target type.
    037     * @return an object of the target type or <code>null</code>.
    038     */
    039    <T> T convert(HttpServletRequest request, Class<T> type);
    040
    041}