ObjectFactory.java

/*
 * Copyright (c) 2004, PostgreSQL Global Development Group
 * See the LICENSE file in the project root for more information.
 */

package org.postgresql.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Properties;

/**
 * Helper class to instantiate objects. Note: the class is <b>NOT</b> public API, so it is subject
 * to change.
 */
public class ObjectFactory {

  /**
   * Instantiates a class using the appropriate constructor. If a constructor with a single
   * Propertiesparameter exists, it is used. Otherwise, if tryString is true a constructor with a
   * single String argument is searched if it fails, or tryString is true a no argument constructor
   * is tried.
   *
   * @param classname Nam of the class to instantiate
   * @param info parameter to pass as Properties
   * @param tryString weather to look for a single String argument constructor
   * @param stringarg parameter to pass as String
   * @return the instantiated class
   * @throws ClassNotFoundException if something goes wrong
   * @throws SecurityException if something goes wrong
   * @throws NoSuchMethodException if something goes wrong
   * @throws IllegalArgumentException if something goes wrong
   * @throws InstantiationException if something goes wrong
   * @throws IllegalAccessException if something goes wrong
   * @throws InvocationTargetException if something goes wrong
   */
  public static Object instantiate(String classname, Properties info, boolean tryString,
      String stringarg) throws ClassNotFoundException, SecurityException, NoSuchMethodException,
          IllegalArgumentException, InstantiationException, IllegalAccessException,
          InvocationTargetException {
    Object[] args = {info};
    Constructor<?> ctor = null;
    Class<?> cls = Class.forName(classname);
    try {
      ctor = cls.getConstructor(Properties.class);
    } catch (NoSuchMethodException nsme) {
      if (tryString) {
        try {
          ctor = cls.getConstructor(String.class);
          args = new String[]{stringarg};
        } catch (NoSuchMethodException nsme2) {
          tryString = false;
        }
      }
      if (!tryString) {
        ctor = cls.getConstructor((Class[]) null);
        args = null;
      }
    }
    return ctor.newInstance(args);
  }

}