JSONValue.java

/*
 * Copyright © 2011 Jason J.A. Stephenson
 * 
 * This file is part of sigio.jar.
 * 
 * sigio.jar is free software: you can redistribute it and/or modify it
 * under the terms of the Lesser GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * sigio.jar is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Lesser GNU General Public License for more details.
 * 
 * You should have received a copy of the Lesser GNU General Public License
 * along with sigio.jar.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.sigio.json;

/**
 * Enum of valid java classes for JSON values.
 */
public enum JSONValue {

  /**
   * Class for JSON objects.
   */
  OBJECT(JSONObject.class),
  /**
   * Class for JSON arrays.
   */
  ARRAY(JSONArray.class),
  /**
   * Class for JSON numbers.
   */
  NUMBER(Number.class),
  /**
   * Class for JSON strings.
   */
  STRING(String.class),
  /**
   * Class (enum) for JSON literal values.
   */
  LITERAL(JSONLiteral.class);

  private final Class<?> klass;

  /**
   * Our hidden constructor.
   */
  JSONValue(Class<?> k) {
    this.klass = k;
  }

  /**
   * Accessor for the class member.
   *
   * @return Class<?> of the specific enum value.
   */
  public Class<?> valueClass() {
    return this.klass;
  }

  /**
   * Returns a string representation of the object.
   *
   * @return The name of class of the specific enum value
   */
  @Override
  public String toString() {
    return this.klass.getName();
  }

  /**
   * Check if a Class can be used as a JSON value.
   *
   * @param k class to check
   * @return <code>true</code> if the class is a viable JSON value
   * class, <code>false</code> if not
   */
  public static boolean isAssignableFrom(Class<?> k) {
    for (JSONValue v : JSONValue.values()) {
      if (v.valueClass().isAssignableFrom(k))
        return true;
    }
    return false;
  }

  /**
   * Check if an instantiated object is a valid JSON value.
   *
   * @param obj object to check
   * @return <code>true</code> if the object is a viable JSON value,
   * <code>false</code> if not
   */
  public static boolean isInstance(Object obj) {
    for (JSONValue v : JSONValue.values()) {
      if (v.valueClass().isInstance(obj))
        return true;
    }
    return false;
  }

}