Java tutorial
/* * 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; } } }