com.ibm.watson.developer_cloud.util.ResponseUtil Maven / Gradle / Ivy
/**
* Copyright 2015 IBM Corp. 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 com.ibm.watson.developer_cloud.util;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.ParseException;
import org.apache.http.util.EntityUtils;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
/**
* Utility class to manage service responses.
*
* @author German Attanasio Ruiz ([email protected])
* @see org.apache.http.HttpResponse HttpResponse
*/
public class ResponseUtil {
/** The Constant log. */
private static final Logger log = Logger.getLogger(ResponseUtil.class
.getName());
/** The Constant BUFFER_SIZE. */
public static final int BUFFER_SIZE = 8192; // 8 kb
/**
* Returns a Json {@link String} in human-readable form.
*
* @param json
* the Json string
* @return the human-readable string
*/
public static String formatJSON(String json) {
try {
JsonParser parser = new JsonParser();
Gson gson = GsonSingleton.getGson();
return gson.toJson(parser.parse(json));
} catch (Exception e) {
log.log(Level.SEVERE,json + " is not valid", e);
return json;
}
}
/**
* Return a {@link JsonElement} representation of the response.
*
* @param response
* the HttpResponse
* @return the content body as JSON
* @throws IOException
* Signals that an I/O exception has occurred.
*/
public static JsonElement getJsonElement(HttpResponse response) throws IOException {
final String json = getString(response);
if (json == null || json.length() == 0)
throw new IOException("JSON response is empty");
JsonElement element = new JsonParser().parse(json);
return element;
}
/**
* Returns a {@link JsonArray} representation of the response.
*
* @param response an HTTP response
* @return the content body as JsonArray
* @throws IOException If an input or output
* exception occurred
*/
public static JsonArray getJsonArray(HttpResponse response)
throws IOException {
final JsonElement json = getJsonElement(response);
return json.getAsJsonArray();
}
/**
* Returns a {@link JsonObject} representation of the response.
*
* @param response an HTTP response
* @return the content body as JSONArray
* @throws IOException If an input or output
* exception occurred
*/
public static JsonObject getJsonObject(HttpResponse response) throws IOException {
return getJsonElement(response).getAsJsonObject();
}
/**
* Returns a String representation of the response.
*
* @param response
* an HTTP response
* @return the content body as String
* @throws IOException
* network error
* */
public static String getString(HttpResponse response) throws IOException {
HttpEntity entity;
try {
entity = response.getEntity();
if (entity == null)
return null;
else
return EntityUtils.toString(entity, "UTF-8");
} catch (ParseException e) {
log.log(Level.SEVERE,"Could not parse service response", e);
throw new IOException("Could not parse service response:" + e.getMessage());
} catch (IOException e) {
log.log(Level.SEVERE,"Could not read service response", e);
throw new IOException("Could not read service response:" + e.getMessage());
}
}
/**
* Returns a String representation of the response.
*
* @param response
* an HTTP response
* @return the content body as String
* @throws IOException
* network error
* */
public static InputStream getInputStream(HttpResponse response) throws IOException {
InputStream is;
try {
is = response.getEntity().getContent();
if (is == null)
return null;
} catch (IOException e) {
log.log(Level.SEVERE,"Could not read service response", e);
throw new IOException("Could not read service response:"
+ e.getMessage());
}
return is;
}
}