org.wso2.msf4j.client.codec.MSF4JJacksonDecoder.java Source code

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Here is the source code for org.wso2.msf4j.client.codec.MSF4JJacksonDecoder.java

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/*
* Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* 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.wso2.msf4j.client.codec;

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.RuntimeJsonMappingException;
import feign.FeignException;
import feign.Response;
import feign.jackson.JacksonDecoder;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.lang.reflect.Type;
import java.util.Collections;

/**
 * Decoder class for decoding error response which also handles error responses with 404 HTTP status code
 */
public class MSF4JJacksonDecoder extends JacksonDecoder {

    private final ObjectMapper mapper;

    public MSF4JJacksonDecoder() {
        this(Collections.<Module>emptyList());
    }

    public MSF4JJacksonDecoder(Iterable<Module> modules) {
        this(new ObjectMapper().configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
                .registerModules(modules));
    }

    public MSF4JJacksonDecoder(ObjectMapper mapper) {
        this.mapper = mapper;
    }

    @Override
    public Object decode(Response response, Type type) throws IOException, FeignException {
        if (response.body() == null) {
            return null;
        }
        Reader reader = response.body().asReader();
        if (!reader.markSupported()) {
            reader = new BufferedReader(reader, 1);
        }
        try {
            // Read the first byte to see if we have any data
            reader.mark(1);
            if (reader.read() == -1) {
                return null; // Eagerly returning null avoids "No content to map due to end-of-input"
            }
            reader.reset();
            return mapper.readValue(reader, mapper.constructType(type));
        } catch (RuntimeJsonMappingException e) {
            Throwable cause = e.getCause();
            if (cause != null && cause instanceof IOException) {
                throw IOException.class.cast(cause);
            }
            throw e;
        }
    }
}