com.clxcommunications.xms.JsonApiAsyncConsumer.java Source code

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Here is the source code for com.clxcommunications.xms.JsonApiAsyncConsumer.java

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/*-
 * #%L
 * SDK for CLX XMS
 * %%
 * Copyright (C) 2016 CLX Communications
 * %%
 * 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.
 * #L%
 */
package com.clxcommunications.xms;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

import org.apache.http.HttpException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.RequestLine;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.InputStreamEntity;
import org.apache.http.nio.IOControl;
import org.apache.http.nio.client.methods.AsyncByteConsumer;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpCoreContext;

import com.clxcommunications.xms.api.ApiError;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * An asynchronous consumer that consumes JSON objects.
 * 
 * @param <T>
 *            the expected type after deserialization
 */
class JsonApiAsyncConsumer<T> extends AsyncByteConsumer<T> {

    private final ObjectMapper json;
    private final Class<T> jsonClass;
    private HttpResponse response;
    private ByteInOutStream bios;

    /**
     * Builds a new JSON consumer.
     * 
     * @param json
     *            the object mapper
     * @param jsonClass
     *            the class that will be deserialized
     */
    public JsonApiAsyncConsumer(ObjectMapper json, Class<T> jsonClass) {
        this.json = json;
        this.jsonClass = jsonClass;
    }

    @Override
    protected void onByteReceived(ByteBuffer buf, IOControl ioctrl) throws IOException {
        bios.write(buf);
    }

    @Override
    protected void onResponseReceived(HttpResponse response) throws HttpException, IOException {
        this.response = response;

        /*
         * We'll assume that most responses fit within 1KiB. For larger
         * responses the output stream will grow automatically.
         */
        this.bios = new ByteInOutStream(1024);
    }

    @Override
    protected T buildResult(HttpContext context) throws Exception {
        int code = response.getStatusLine().getStatusCode();
        InputStream inputStream = bios.toInputStream();

        switch (code) {
        case HttpStatus.SC_OK:
        case HttpStatus.SC_CREATED:
            return json.readValue(inputStream, jsonClass);
        case HttpStatus.SC_BAD_REQUEST:
        case HttpStatus.SC_FORBIDDEN:
            ApiError error = json.readValue(inputStream, ApiError.class);
            throw new ErrorResponseException(error);
        case HttpStatus.SC_NOT_FOUND:
            HttpCoreContext coreContext = HttpCoreContext.adapt(context);
            RequestLine rl = coreContext.getRequest().getRequestLine();
            throw new NotFoundException(rl.getUri());
        case HttpStatus.SC_UNAUTHORIZED:
            throw new UnauthorizedException();
        default:
            ContentType type = ContentType.getLenient(response.getEntity());
            InputStreamEntity entity = new InputStreamEntity(inputStream, bios.size(), type);
            response.setEntity(entity);
            throw new UnexpectedResponseException(response);
        }
    }

}