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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 2008-2022 Ping Identity Corporation
 * All Rights Reserved.
 */
/*
 * Copyright 2008-2022 Ping Identity Corporation
 *
 * 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.
 */
/*
 * Copyright (C) 2008-2022 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.concurrent.atomic.AtomicLong;



/**
 * This class defines a sequential numeric value pattern component, which will
 * generate numeric values in sequential order, optionally using an increment
 * and format string.
 */
final class SequentialValuePatternComponent
      extends ValuePatternComponent
{
  /**
   * The serial version UID for this serializable class.
   */
  private static final long serialVersionUID = -3553865579642557953L;



  // The next value to return.
  @NotNull private final AtomicLong nextValue;

  // The increment for this component.
  private final long increment;

  // The lower bound for this component.
  private final long lowerBound;

  // The upper bound for this component.
  private final long upperBound;

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

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



  /**
   * Creates a new sequential 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  increment     The increment that will be used by this component.
   * @param  formatString  The format string that will be used by this
   *                       component, if any.
   */
  SequentialValuePatternComponent(final long lowerBound, final long upperBound,
                                  final long increment,
                                  @Nullable final String formatString)
  {
    if (lowerBound == upperBound)
    {
      this.lowerBound = lowerBound;
      this.upperBound = upperBound;
      this.increment  = 0L;
    }
    else if (lowerBound > upperBound)
    {
      this.lowerBound = upperBound;
      this.upperBound = lowerBound;

      if (Math.abs(increment) > (lowerBound - upperBound))
      {
        this.increment = 0L;
      }
      else
      {
        this.increment  = -1L * increment;
      }
    }
    else
    {
      this.lowerBound = lowerBound;
      this.upperBound = upperBound;

      if (Math.abs(increment) > (upperBound - lowerBound))
      {
        this.increment = 0L;
      }
      else
      {
        this.increment = increment;
      }
    }

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



  /**
   * {@inheritDoc}
   */
  @Override()
  void append(@NotNull final StringBuilder buffer)
  {
    long value = nextValue.getAndAdd(increment);
    if (value > upperBound)
    {
      if (nextValue.compareAndSet(value+increment, lowerBound))
      {
        value = nextValue.getAndAdd(increment);
      }
      else
      {
        while (true)
        {
          final long v = nextValue.get();
          if ((v < upperBound) || nextValue.compareAndSet(v, lowerBound))
          {
            value = nextValue.getAndAdd(increment);
            break;
          }
        }
      }
    }
    else if (value < lowerBound)
    {
      if (nextValue.compareAndSet(value+increment, upperBound))
      {
        value = nextValue.getAndAdd(increment);
      }
      else
      {
        while (true)
        {
          final long v = nextValue.get();
          if ((v > lowerBound) || nextValue.compareAndSet(v, upperBound))
          {
            value = nextValue.getAndAdd(increment);
            break;
          }
        }
      }
    }

    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;
  }
}