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The UnboundID LDAP SDK for Java is a fast, comprehensive, and easy-to-use Java API for communicating with LDAP directory servers and performing related tasks like reading and writing LDIF, encoding and decoding data using base64 and ASN.1 BER, and performing secure communication. This package contains the Standard Edition of the LDAP SDK, which is a complete, general-purpose library for communicating with LDAPv3 directory servers.

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/*
 * Copyright 2008-2018 Ping Identity Corporation
 * All Rights Reserved.
 */
/*
 * Copyright (C) 2008-2018 Ping Identity Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (GPLv2 only)
 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
 * as published by the Free Software Foundation.
 *
 * This program 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see .
 */
package com.unboundid.util;



import java.text.DecimalFormat;
import java.util.Random;



/**
 * This class defines a random numeric value pattern component, which will
 * generate numeric values chosen randomly from a given range, optionally using
 * a format string.
 */
final class RandomValuePatternComponent
      extends ValuePatternComponent
{
  /**
   * The serial version UID for this serializable class.
   */
  private static final long serialVersionUID = -670528378158953667L;



  // The lower bound for generated values.
  private final long lowerBound;

  // The span for generated values.
  private final long span;

  // The random number generator that will be used to seed the thread-local
  // generators.
  private final Random seedRandom;

  // The format string that will be used by the decimal formatter.
  private final String formatString;

  // The decimal format that will be used by this component, if applicable.
  private final ThreadLocal decimalFormat;

  // The random number generator that will be used by this component.
  private final ThreadLocal random;



  /**
   * Creates a new random numeric value pattern component with the provided
   * information.
   *
   * @param  lowerBound    The lower bound that will be used by this component.
   * @param  upperBound    The upper bound that will be used by this component.
   * @param  seed          The value that will be used to seed the initial
   *                       random number generator.
   * @param  formatString  The format string that will be used by this
   *                       component, if any.
   */
  RandomValuePatternComponent(final long lowerBound, final long upperBound,
                              final long seed, final String formatString)
  {
    if (lowerBound == upperBound)
    {
      this.lowerBound = lowerBound;

      span = 1L;
    }
    else if (lowerBound > upperBound)
    {
      this.lowerBound = upperBound;

      span = lowerBound - upperBound + 1;
    }
    else
    {
      this.lowerBound = lowerBound;

      span = upperBound - lowerBound + 1;
    }

    seedRandom = new Random(seed);
    random     = new ThreadLocal<>();

    this.formatString = formatString;
    decimalFormat     = new ThreadLocal<>();
  }



  /**
   * {@inheritDoc}
   */
  @Override()
  void append(final StringBuilder buffer)
  {
    Random r = random.get();
    if (r == null)
    {
      r = new Random(seedRandom.nextLong());
      random.set(r);
    }

    final long value = ((r.nextLong() & 0x7FFF_FFFF) % span) + lowerBound;
    if (formatString == null)
    {
      buffer.append(value);
    }
    else
    {
      DecimalFormat f = decimalFormat.get();
      if (f == null)
      {
        f = new DecimalFormat(formatString);
        decimalFormat.set(f);
      }

      buffer.append(f.format(value));
    }
  }



  /**
   * {@inheritDoc}
   */
  @Override()
  boolean supportsBackReference()
  {
    return true;
  }
}