org.nobel.highriseapi.mapper.SimpleXmlHttpMessageConverter.java Source code

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Here is the source code for org.nobel.highriseapi.mapper.SimpleXmlHttpMessageConverter.java

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/*
 * Copyright 2011 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.nobel.highriseapi.mapper;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;

import org.simpleframework.xml.Root;
import org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;
import org.springframework.beans.TypeMismatchException;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.util.Assert;

/**
 * Implementation of
 * {@link org.springframework.http.converter.HttpMessageConverter
 * HttpMessageConverter} that can read and write XML using Simple's
 * {@link Serializer} abstraction. *
 * <p>
 * By default, this converter supports {@code text/xml} and
 * {@code application/xml}. This can be overridden by setting the
 * {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} property.
 * 
 * @author Roy Clarkson
 * @since 1.0
 */
public class SimpleXmlHttpMessageConverter extends AbstractHttpMessageConverter<Object> {

    public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");

    private Serializer serializer;

    /**
     * Construct a new {@code SimpleXmlHttpMessageConverter} with a default
     * {@link Serializer}. Sets the
     * {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} to
     * {@code text/xml} and {@code application/xml}, and
     * {@code application/*+xml}.
     */
    public SimpleXmlHttpMessageConverter() {
        this(new Persister());
    }

    /**
     * Construct a new {@code SimpleXmlHttpMessageConverter} with a customized
     * {@link Serializer}. Sets the
     * {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} to
     * {@code text/xml} and {@code application/xml}, and
     * {@code application/*-xml}.
     */
    public SimpleXmlHttpMessageConverter(Serializer serializer) {
        super(MediaType.APPLICATION_XML, MediaType.TEXT_XML);
        setSerializer(serializer);
    }

    @Override
    public boolean canRead(Class<?> clazz, MediaType mediaType) {
        return canRead(mediaType);
    }

    @Override
    public boolean canWrite(Class<?> clazz, MediaType mediaType) {
        return clazz.isAnnotationPresent(Root.class) && canWrite(mediaType);
    }

    /**
     * Sets the {@code Serializer} for this view. If not set, a default
     * {@link Serializer} is used.
     * <p>
     * Setting a custom-configured {@code Serializer} is one way to take further
     * control of the XML serialization process.
     * 
     * @throws IllegalArgumentException
     *             if serializer is null
     */
    public void setSerializer(Serializer serializer) {
        Assert.notNull(serializer, "'serializer' must not be null");
        this.serializer = serializer;
    }

    @Override
    protected Object readInternal(Class<? extends Object> clazz, HttpInputMessage inputMessage)
            throws IOException, HttpMessageNotReadableException {

        Reader source = new InputStreamReader(inputMessage.getBody(), getCharset(inputMessage.getHeaders()));

        try {
            Object result = this.serializer.read(clazz, source);
            if (!clazz.isInstance(result)) {
                throw new TypeMismatchException(result, clazz);
            }
            return result;
        } catch (Exception ex) {
            throw new HttpMessageNotReadableException("Could not read [" + clazz + "]", ex);
        }
    }

    @Override
    protected boolean supports(Class<?> clazz) {
        // should not be called, since we override canRead/Write
        throw new UnsupportedOperationException();
    }

    @Override
    protected void writeInternal(Object o, HttpOutputMessage outputMessage)
            throws IOException, HttpMessageNotWritableException {

        Writer out = new OutputStreamWriter(outputMessage.getBody(), getCharset(outputMessage.getHeaders()));

        try {
            this.serializer.write(o, out);
            out.close();
        } catch (Exception ex) {
            throw new HttpMessageNotWritableException("Could not write [" + o + "]", ex);
        }
    }

    // helpers

    private Charset getCharset(HttpHeaders headers) {
        if (headers != null && headers.getContentType() != null && headers.getContentType().getCharSet() != null) {
            return headers.getContentType().getCharSet();
        }
        return DEFAULT_CHARSET;
    }

}