JsonUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.twill.internal.json;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

/**
 * Collections of helper functions for json codec.
 */
public final class JsonUtils {

  private JsonUtils() {
  }

  /**
   * Returns a String representation of the given property.
   */
  public static String getAsString(JsonObject json, String property) {
    JsonElement jsonElement = json.get(property);
    if (jsonElement == null || jsonElement.isJsonNull()) {
      return null;
    }
    if (jsonElement.isJsonPrimitive()) {
      return jsonElement.getAsString();
    }
    return jsonElement.toString();
  }

  /**
   * Returns a long representation of the given property.
   */
  public static long getAsLong(JsonObject json, String property, long defaultValue) {
    try {
      return json.get(property).getAsLong();
    } catch (Exception e) {
      return defaultValue;
    }
  }

  /**
   * Returns a long representation of the given property.
   */
  public static int getAsInt(JsonObject json, String property, int defaultValue) {
    try {
      return json.get(property).getAsInt();
    } catch (Exception e) {
      return defaultValue;
    }
  }
}