001/*
002 * Copyright 2002-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.messaging.converter;
018
019import java.nio.charset.Charset;
020
021import org.springframework.messaging.Message;
022import org.springframework.messaging.MessageHeaders;
023import org.springframework.util.MimeType;
024
025/**
026 * A {@link MessageConverter} that supports MIME type "text/plain" with the
027 * payload converted to and from a String.
028 *
029 * @author Rossen Stoyanchev
030 * @since 4.0
031 */
032public class StringMessageConverter extends AbstractMessageConverter {
033
034        private final Charset defaultCharset;
035
036
037        public StringMessageConverter() {
038                this(Charset.forName("UTF-8"));
039        }
040
041        public StringMessageConverter(Charset defaultCharset) {
042                super(new MimeType("text", "plain", defaultCharset));
043                this.defaultCharset = defaultCharset;
044        }
045
046
047        @Override
048        protected boolean supports(Class<?> clazz) {
049                return (String.class == clazz);
050        }
051
052        @Override
053        protected Object convertFromInternal(Message<?> message, Class<?> targetClass, Object conversionHint) {
054                Charset charset = getContentTypeCharset(getMimeType(message.getHeaders()));
055                Object payload = message.getPayload();
056                return (payload instanceof String ? payload : new String((byte[]) payload, charset));
057        }
058
059        @Override
060        protected Object convertToInternal(Object payload, MessageHeaders headers, Object conversionHint) {
061                if (byte[].class == getSerializedPayloadClass()) {
062                        Charset charset = getContentTypeCharset(getMimeType(headers));
063                        payload = ((String) payload).getBytes(charset);
064                }
065                return payload;
066        }
067
068        private Charset getContentTypeCharset(MimeType mimeType) {
069                if (mimeType != null && mimeType.getCharset() != null) {
070                        return mimeType.getCharset();
071                }
072                else {
073                        return this.defaultCharset;
074                }
075        }
076
077}