/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.http.converter;
import java.io.IOException;
import java.nio.charset.Charset;
import org.springframework.core.convert.ConversionService;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.util.Assert;
/**
* An {@code HttpMessageConverter} that uses {@link StringHttpMessageConverter}
* for reading and writing content and a {@link ConversionService} for converting
* the String content to and from the target object type.
* <p>
* By default, this converter supports the media type {@code text/plain} only.
* This can be overridden by setting the
* {@link #setSupportedMediaTypes supportedMediaTypes} property.
*
* @author <a href="mailto:dmitry.katsubo@gmail.com">Dmitry Katsubo</a>
* @author Rossen Stoyanchev
* @since 2.0
*/
public class ObjectToStringHttpMessageConverter extends AbstractHttpMessageConverter<Object> {
private ConversionService conversionService;
private StringHttpMessageConverter stringHttpMessageConverter;
/**
* A constructor accepting a {@code ConversionService} to use to convert the
* (String) message body to/from the target class type. This constructor
* uses {@link StringHttpMessageConverter#DEFAULT_CHARSET} as the default
* charset.
*
* @param conversionService the conversion service
*/
public ObjectToStringHttpMessageConverter(ConversionService conversionService) {
this(conversionService, StringHttpMessageConverter.DEFAULT_CHARSET);
}
/**
* A constructor accepting a {@code ConversionService} as well as a default
* charset.
*
* @param conversionService the conversion service
* @param defaultCharset the default charset
*/
public ObjectToStringHttpMessageConverter(ConversionService conversionService, Charset defaultCharset) {
super(new MediaType("text", "plain", defaultCharset));
Assert.notNull(conversionService, "conversionService is required");
this.conversionService = conversionService;
this.stringHttpMessageConverter = new StringHttpMessageConverter(defaultCharset);
}
/**
* Indicates whether the {@code Accept-Charset} should be written to any outgoing request.
* <p>Default is {@code true}.
*/
public void setWriteAcceptCharset(boolean writeAcceptCharset) {
this.stringHttpMessageConverter.setWriteAcceptCharset(writeAcceptCharset);
}
@Override
public boolean canRead(Class<?> clazz, MediaType mediaType) {
return this.conversionService.canConvert(String.class, clazz) && canRead(mediaType);
}
@Override
public boolean canWrite(Class<?> clazz, MediaType mediaType) {
return this.conversionService.canConvert(clazz, String.class) && canWrite(mediaType);
}
@Override
protected boolean supports(Class<?> clazz) {
// should not be called, since we override canRead/Write
throw new UnsupportedOperationException();
}
@Override
protected Object readInternal(Class<? extends Object> clazz, HttpInputMessage inputMessage) throws IOException {
String value = this.stringHttpMessageConverter.readInternal(String.class, inputMessage);
return this.conversionService.convert(value, clazz);
}
@Override
protected void writeInternal(Object obj, HttpOutputMessage outputMessage) throws IOException {
String s = this.conversionService.convert(obj, String.class);
this.stringHttpMessageConverter.writeInternal(s, outputMessage);
}
@Override
protected Long getContentLength(Object obj, MediaType contentType) {
String value = this.conversionService.convert(obj, String.class);
return this.stringHttpMessageConverter.getContentLength(value, contentType);
}
}