DeserializeFilters.java

package qa.qcri.aidr.common.filter;


import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

public class DeserializeFilters {
	
	private static Logger logger = Logger.getLogger(DeserializeFilters.class);
	
	public DeserializeFilters() {}
	
	public JsonQueryList deserializeConstraints(final String queryString) {
		Gson jsonObject = new GsonBuilder().serializeNulls().disableHtmlEscaping()
				.serializeSpecialFloatingPointValues()	
				.create();
		if(!StringUtils.isEmpty(queryString)){
			JsonParser parser = new JsonParser();
			JsonObject obj = (JsonObject) parser.parse(queryString);
			JsonArray constraintsArray = null;
			if (obj.has("constraints")) {					// should always be true
				constraintsArray = obj.get("constraints") != null ? obj.get("constraints").getAsJsonArray() : new JsonArray();
				//logger.debug("constraints: " + constraintsArray);
			}
			JsonQueryList queryList = new JsonQueryList();
			if (constraintsArray.size() > 0) {
				for (int i = 0;i < constraintsArray.size();i++) {
					try {
						JsonElement q = constraintsArray.get(i);
						//System.out.println("constraint " + i + ": " + q);
						GenericInputQuery constraint = jsonObject.fromJson(q, GenericInputQuery.class);
						queryList.createConstraint(constraint);
					} catch (Exception e) {
						logger.error("Error in deserializing received constraints",e);
						return null;
					}
				}
			}

			logger.debug("Output: deserialized queryList: " + queryList);
			return queryList;
		}
		logger.debug("Output: deserialized queryList: null" );
		return null;
	}
}