org.aesop.serializer.batch.reader.UserInfoServiceReader.java Source code

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Here is the source code for org.aesop.serializer.batch.reader.UserInfoServiceReader.java

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/*
 * Copyright 2012-2015, 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.aesop.serializer.batch.reader;

import org.aesop.serializer.model.UserInfo;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.item.ItemStreamException;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputException;
import org.trpr.platform.batch.common.BatchException;
import org.trpr.platform.batch.impl.spring.reader.CompositeItemStreamReader;
import org.trpr.platform.batch.spi.spring.reader.BatchItemStreamReader;

/**
 * The <code>UserInfoServiceReader</code> class is a simple implementation of the {@link BatchItemStreamReader} that returns the sample data item {@link UserInfo} instances
 * from JSON over REST calls to a deployed service.
 * 
 * @author Regunath B
 * @version 1.0, 29 Feb 2014
 */

public class UserInfoServiceReader<T extends UserInfo> implements BatchItemStreamReader<UserInfo> {

    /** The service endpoint URL. Note: This is for testing and very specific to this sample*/
    private static final String SERVICE_URL = "http://localhost:25151/userservice/v0.1/customer";

    /** The ObjectMapper to use for JSON deserialization*/
    private ObjectMapper objectMapper = new ObjectMapper();

    /** A set of fictitious phone numbers to perform lookup on*/
    private static final String[] PHONE_NUMBERS = { "6543217890", "6543217891", "9090912345", "9586545778",
            "9632828337", "9740417580", "9845452123", "9876543210", "9898989898", "9933551100", };

    /**
     * Returns a number of {@link UserInfo} instances looked up from a service end-point.
     * Note : The end-point and parameters used here are very specific to this sample. Also the code is mostly for testing and production 
     * ready (no Http connection pools etc.) 
     * @see org.trpr.platform.batch.spi.spring.reader.BatchItemStreamReader#batchRead(org.springframework.batch.item.ExecutionContext)
     */
    public UserInfo[] batchRead(ExecutionContext context)
            throws Exception, UnexpectedInputException, ParseException {
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        UserInfo[] results = new UserInfo[PHONE_NUMBERS.length];
        for (int i = 0; i < PHONE_NUMBERS.length; i++) {
            DefaultHttpClient httpclient = new DefaultHttpClient();
            HttpGet executionGet = new HttpGet(SERVICE_URL);
            URIBuilder uriBuilder = new URIBuilder(executionGet.getURI());
            uriBuilder.addParameter("primary_phone", PHONE_NUMBERS[i]);
            uriBuilder.addParameter("require", "{\"preferences\":true,\"addresses\":true}");
            ((HttpRequestBase) executionGet).setURI(uriBuilder.build());
            HttpResponse httpResponse = httpclient.execute(executionGet);
            String response = new String(EntityUtils.toByteArray(httpResponse.getEntity()));
            SearchResult searchResult = objectMapper.readValue(response, SearchResult.class);
            results[i] = searchResult.results[0]; // we take only the first result
        }
        return results;
    }

    /**
     * Interface method implementation. Throws an exception suggesting to use the {@link #batchRead()} method instead via the {@link CompositeItemStreamReader} instead
     * @see org.springframework.batch.item.ItemReader#read()
     */
    public UserInfo read() throws Exception, UnexpectedInputException, ParseException {
        throw new BatchException(
                "Operation is not supported! Use the CompositeItemStreamReader#read() method instead.");
    }

    /** No Op methods. These callbacks may be implemented in production systems to do stuff like Http client connection pool setup and tear down*/
    public void open(ExecutionContext context) throws ItemStreamException {
    }

    public void update(ExecutionContext context) throws ItemStreamException {
    }

    public void close() throws ItemStreamException {
    }
}