com.github.wnameless.json.base.JsonValueUtils Maven / Gradle / Ivy

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/*
 *
 * Copyright 2020 Wei-Ming Wu
 *
 * 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.github.wnameless.json.base;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 
 * {@link JsonValueUtils} provides convenient methods to generate Java objects
 * from any JSON wrapper in this library.
 * 
 * @author Wei-Ming Wu
 *
 */
public final class JsonValueUtils {

  private JsonValueUtils() {}

  /**
   * Creates a Java {@link Object} from given {@link JsonValueBase}.
   * 
   * @param jsonValue
   *          a {@link JsonValueBase}
   * @return an {@link Object} corresponds to JSON value
   * @throws IllegalStateException
   *           if given {@link JsonValueBase} is not represented as any JSON
   *           value
   */
  public static Object toObject(JsonValueBase jsonValue) {
    if (jsonValue.isNull()) return jsonValue.asNull();
    if (jsonValue.isBoolean()) return jsonValue.asBoolean();
    if (jsonValue.isString()) return jsonValue.asString();
    if (jsonValue.isNumber()) return jsonValue.asNumber();
    if (jsonValue.isArray()) return toList(jsonValue.asArray());
    if (jsonValue.isObject()) return toMap(jsonValue.asObject());
    throw new IllegalStateException();
  }

  /**
   * Creates a {@link Number} by given {@link BigDecimal} from {@link Integer},
   * {@link Long}, {@link BigInteger}, {@link Double} and {@link BigDecimal}
   * based on the size and scale of numeric.
   * 
   * @param bd
   *          a {@link BigDecimal}
   * @return a {@link Number}
   */
  public static Number toJavaNumber(BigDecimal bd) {
    if (BigDecimal.valueOf(bd.intValue()).equals(bd)) {
      return bd.intValue();
    }
    if (BigDecimal.valueOf(bd.longValue()).equals(bd)) {
      return bd.longValue();
    }
    if (bd.scale() <= 0) {
      return bd.toBigInteger();
    }
    if (BigDecimal.valueOf(bd.doubleValue()).compareTo(bd) == 0) {
      return bd.doubleValue();
    }
    return bd;
  }

  /**
   * Creates a {@link List} by given {@link JsonArrayBase}.
   * 
   * @param jsonArray
   *          a {@link JsonArrayBase}
   * @return a {@link List}
   */
  public static List