com.excilys.spring.mom.parser.MOMResponseJSONAttributesParser.java Source code

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Here is the source code for com.excilys.spring.mom.parser.MOMResponseJSONAttributesParser.java

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/**
 * Copyright 2010-2011 eBusiness Information, Groupe Excilys (www.excilys.com)
 *
 * 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 com.excilys.spring.mom.parser;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.commons.codec.binary.Base64;

import com.excilys.spring.mom.annotation.MOMAttributeEncoding;
import com.fasterxml.jackson.core.type.TypeReference;

/**
 * Concrete class implemented {@link MOMResponseParser MOMResponseParser}.
 * <p/>
 * This implementation parse data as a JSON string. Each annotated method parameters will try to be mapped with the
 * according value of the JSON oject.
 * <p/>
 * According the client receive the JSON string <code>'{var1:value1, var2:value2, var3:value3}'</code> on a subscribed
 * topic and the mapping method signature is the following :
 * <p/>
 * <code>@MOMMapping(topic = "topic", consumes = MOMMappingConsum.JSON)
 * public void received(@MOMAttribute("var1") String param1, @MOMAttribute("var3") String param2) {...}</code>
 * <p/>
 * Then the method invoke will be like this : <code>received("value1", "value3");</code>
 * 
 * @author dvilleneuve
 * @see MOMResponseParser
 */
public class MOMResponseJSONAttributesParser implements MOMResponseParser {

    private final ParameterInfo[] bindAttributes;

    public MOMResponseJSONAttributesParser(ParameterInfo[] bindAttributes) {
        this.bindAttributes = bindAttributes;
    }

    @Override
    public Object[] parse(byte[] data) throws MOMResponseParsingException {
        if (data == null || data.length == 0) {
            throw new MOMResponseParsingException("The json string is empty");
        }

        List<Object> results = new ArrayList<Object>();
        Map<String, Object> jsonMap;

        try {
            jsonMap = ObjectMapperSingleton.INSTANCE.getMapper().readValue(data,
                    new TypeReference<Map<String, Object>>() {
                    });
        } catch (IOException e) {
            throw new MOMResponseParsingException("Unable to parse the json string : " + new String(data), e);
        }

        // For each annotated parameter, try to get back the json value according to the key
        for (ParameterInfo bindAttribute : bindAttributes) {
            Object attributeValue = jsonMap.get(bindAttribute.getName());

            // Decode a base64 encoded string
            if (bindAttribute.getEncoding() == MOMAttributeEncoding.BASE64) {
                if (attributeValue instanceof String) {
                    attributeValue = Base64.decodeBase64((String) attributeValue);
                } else if (attributeValue instanceof byte[]) {
                    attributeValue = Base64.decodeBase64((byte[]) attributeValue);
                }
            }

            if (attributeValue != null) {
                results.add(attributeValue);
            }
        }

        return results.toArray();
    }
}