org.eclipse.emf.ecp.emf2web.json.JSONCrudOperator.java Source code

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Here is the source code for org.eclipse.emf.ecp.emf2web.json.JSONCrudOperator.java

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/*******************************************************************************
 * Copyright (c) 2014-2015 EclipseSource Muenchen GmbH and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Stefan Dirix - initial API and implementation
 *
 *******************************************************************************/
package org.eclipse.emf.ecp.emf2web.json;

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

import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class JSONCrudOperator {

    public List<Map<String, Object>> readElements(String url, String type) throws IOException {
        final List<Map<String, Object>> result = new ArrayList<Map<String, Object>>();

        final CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            final HttpGet httpGet = new HttpGet(url + "/" + type);

            final JSONResponseHandler<List<Map<String, Object>>> responseHandler = new JSONResponseHandler<List<Map<String, Object>>>();

            final List<Map<String, Object>> resultList = responseHandler
                    .handleResponse(httpClient.execute(httpGet));

            for (final Map<String, Object> object : resultList) {
                if (object == null) {
                    continue;
                }

                result.add(object);
            }
        } finally {
            httpClient.close();
        }

        return result;
    }

    public Map<String, Object> createElement(String url, String type, Map<String, Object> jsonDescription)
            throws IOException {
        final String completeUrl = url + "/" + type;
        final Map<String, Object> response = sendPost(completeUrl, jsonDescription);
        return response;
    }

    public boolean updateElement(String url, String type, String id, Map<String, Object> element)
            throws IOException {
        final String completeUrl = url + "/" + type + "/" + id;
        sendPost(completeUrl, element);
        return true;
    }

    /**
     * @deprecated not yet implemented
     */
    @Deprecated
    public boolean deleteElement(String url, String type, String id, Map<String, Object> element)
            throws IOException {
        return false;
    }

    private Map<String, Object> sendPost(String completeUrl, Map<String, Object> element) throws IOException {
        final CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            final HttpPost postRequest = new HttpPost(completeUrl);

            final Gson gson = new GsonBuilder().create();
            final String json = gson.toJson(element);

            postRequest.setEntity(new StringEntity(json, ContentType.create("application/json")));

            final JSONResponseHandler<Map<String, Object>> responseHandler = new JSONResponseHandler<Map<String, Object>>();

            final Map<String, Object> response = responseHandler.handleResponse(httpClient.execute(postRequest));

            return response;
        } finally {
            httpClient.close();
        }
    }
}