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/*
* The MIT License
*
* Copyright 2010 Sony Ericsson Mobile Communications.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.sonyericsson.hudson.plugins.gerrit.gerritevents;
import com.sonyericsson.hudson.plugins.gerrit.gerritevents.dto.GerritEventType;
import com.sonyericsson.hudson.plugins.gerrit.gerritevents.dto.GerritJsonEvent;
import java.lang.reflect.Constructor;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Contains utility methods for handling JSONObjects.
* @author Robert Sandell <[email protected]>
*/
public final class GerritJsonEventFactory {
private static final Logger logger = LoggerFactory.getLogger(GerritJsonEventFactory.class);
/**
* Empty private Constructor to hinder instantiation.
*/
private GerritJsonEventFactory() {
//Empty
}
/**
* Creates a GerritJsonEvent DTO out of the provided JSONObject.
* The jsonObject is assumed to be interesting and usable
* as defined by {@link #getJsonObjectIfInterestingAndUsable(java.lang.String) }
* @param jsonObject the parsed JSON Object
* @return the POJO DTO representation of the jsonObject.
*/
public static GerritJsonEvent getEvent(JSONObject jsonObject) {
GerritEventType type = GerritEventType.findByTypeValue(jsonObject.getString("type"));
//the type has already been verified by the method that gets the JSONObject,
//so any NullPointerExceptions or similar problems are the caller's own fault.
Class clazz = type.getEventRepresentative();
GerritJsonEvent event = null;
try {
logger.debug("Interesting event with a class defined. Searching shorthand constructor.");
Constructor constructor = clazz.getConstructor(JSONObject.class);
event = constructor.newInstance(jsonObject);
logger.trace("Event created from shorthand constructor.");
} catch (NoSuchMethodException ex) {
logger.debug("Constructor with JSONObject as parameter missing, trying default constructor.", ex);
} catch (Exception ex) {
logger.debug("Error when using event constructor with JSONObject, trying default constructor.", ex);
}
if (event == null) {
logger.debug("Trying default constructor.");
try {
event = clazz.newInstance();
event.fromJson(jsonObject);
logger.trace("Event created from default constructor");
} catch (InstantiationException ex) {
logger.error("Could not create an interesting GerritJsonEvent via default constructor "
+ "(DESIGN ERROR).", ex);
} catch (IllegalAccessException ex) {
logger.error("Could not create an interesting GerritJsonEvent via default constructor"
+ "(DESIGN ERROR).", ex);
}
}
logger.debug("Returning an event: {}", event);
return event;
}
/**
* Tells if the provided string is a valid JSON string
* and represents an interesting and usable {@link GerritJsonEvent}
* as defined by {@link #getJsonObjectIfInterestingAndUsable(java.lang.String) }.
* This is the same as doing {@code (getJsonObjectIfInterestingAndUsable(jsonString) != null)}
* @param jsonString the JSON formatted String.
* @return true if it is so.
*/
public static boolean isInterestingAndUsable(String jsonString) {
return getJsonObjectIfInterestingAndUsable(jsonString) != null;
}
/**
* Tries to parse the provided string into a JSONObject and returns it if it is interesting and usable.
* If it is interesting is determined by:
*
* - The object contains a String field named type
* - The String returns a non null GerritEventType from
* {@link GerritEventType#findByTypeValue(java.lang.String) }
* - The property {@link GerritEventType#isInteresting() } == true
*
* It is usable if the type's {@link GerritEventType#getEventRepresentative() } is not null.
* @param jsonString the string to parse.
* @return an interesting and usable JSONObject, or null if it is not.
*/
public static JSONObject getJsonObjectIfInterestingAndUsable(String jsonString) {
logger.trace("finding event for jsonString: {}", jsonString);
if (jsonString == null || jsonString.length() <= 0) {
return null;
}
try {
JSONObject jsonObject = (JSONObject)JSONSerializer.toJSON(jsonString);
logger.debug("Parsed a JSONObject");
if (jsonObject.get("type") != null) {
logger.trace("It has a type");
GerritEventType type = GerritEventType.findByTypeValue(jsonObject.getString("type"));
logger.debug("Type found: {}", type);
if (type != null && type.isInteresting() && type.getEventRepresentative() != null) {
logger.debug("It is interesting and usable.");
return jsonObject;
}
}
} catch (Exception ex) {
logger.warn("Unanticipated error when examining JSON String", ex);
}
return null;
}
/**
* Tries to parse the provided string into a GerritJsonEvent DTO if it is interesting and usable.
* @param jsonString the JSON formatted string.
* @return the Event.
* @see #getJsonObjectIfInterestingAndUsable(String)
*/
public static GerritJsonEvent getEventIfInteresting(String jsonString) {
logger.trace("finding event for jsonString: {}", jsonString);
try {
JSONObject jsonObject = getJsonObjectIfInterestingAndUsable(jsonString);
if (jsonObject != null) {
return getEvent(jsonObject);
}
} catch (Exception ex) {
logger.warn("Unanticipated error when creating DTO representation of JSON string.", ex);
}
return null;
}
/**
* Returns the value of a JSON property as a String if it exists otherwise returns the defaultValue.
* @param json the JSONObject to check.
* @param key the key
* @param defaultValue the value to return if the key is missing
* @return the value for the key as a string.
*/
public static String getString(JSONObject json, String key, String defaultValue) {
if (json.containsKey(key)) {
return json.getString(key);
} else {
return defaultValue;
}
}
/**
* Returns the value of a JSON property as a String if it exists otherwise returns null.
* Same as calling {@link #getString(net.sf.json.JSONObject, java.lang.String, java.lang.String) }
* with null as defaultValue.
* @param json the JSONObject to check.
* @param key the key
* @return the value for the key as a string.
*/
public static String getString(JSONObject json, String key) {
return getString(json, key, null);
}
}