/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE
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* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
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* add the following below this CDDL HEADER, with the fields enclosed
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* by brackets "[]" replaced with your own identifying * information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Portions Copyright 2006 Sun Microsystems, Inc.
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*/
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package org.opends.server.backends.jeb;
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import com.sleepycat.je.DatabaseEntry;
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import java.util.concurrent.atomic.AtomicLong;
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/**
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* An integer identifier assigned to each entry in the JE backend.
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* An entry ID is implemented by this class as a long.
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* There are static methods to assign monotonically increasing entry IDs,
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* starting from 1.
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*/
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public class EntryID implements Comparable<EntryID>
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{
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/**
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* The cached value of the next identifier to be assigned.
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*/
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private static AtomicLong nextid = new AtomicLong(1);
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/**
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* The identifier integer value.
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*/
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private final Long id;
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/**
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* The value in database format, created when necessary.
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*/
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private DatabaseEntry data = null;
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/**
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* Create a new entry ID object from a given long value.
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* @param id The long value of the ID.
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*/
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public EntryID(long id)
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{
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this.id = id;
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}
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/**
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* Create a new entry ID object from a given Long value.
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* @param id the Long value of the ID.
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*/
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public EntryID(Long id)
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{
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this.id = id;
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}
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/**
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* Create a new entry ID object from a value in database format.
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* @param databaseEntry The database value of the ID.
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*/
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public EntryID(DatabaseEntry databaseEntry)
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{
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data = databaseEntry;
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id = JebFormat.entryIDFromDatabase(data.getData());
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}
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/**
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* Get the value of the entry ID as a long.
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* @return The entry ID.
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*/
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public long longValue()
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{
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return id;
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}
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/**
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* Get the value of the ID in database format.
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* @return The value of the ID in database format.
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*/
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public DatabaseEntry getDatabaseEntry()
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{
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if (data == null)
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{
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data = new DatabaseEntry();
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data.setData(JebFormat.entryIDToDatabase(id));
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}
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return data;
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}
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/**
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* Initialize the next ID counter from the previous highest value.
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* @param highestID The previous highest entry ID.
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*/
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public static void initialize(EntryID highestID)
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{
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nextid = new AtomicLong(highestID.id + 1);
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}
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/**
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* Assign the next entry ID.
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* @return The assigned entry ID.
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*/
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public static EntryID assignNext()
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{
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return new EntryID(nextid.getAndIncrement());
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}
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/**
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* Return the lowest entry ID assigned.
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* @return The lowest entry ID assigned.
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*/
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public static Long getLowest()
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{
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return 1L;
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}
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/**
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* Return the highest entry ID assigned.
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* @return The highest entry ID assigned.
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*/
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public static Long getHighest()
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{
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return (nextid.get() - 1);
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}
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/**
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* Compares this object with the specified object for order. Returns a
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* negative integer, zero, or a positive integer as this object is less
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* than, equal to, or greater than the specified object.<p>
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* <p/>
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*
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* @param that the Object to be compared.
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* @return a negative integer, zero, or a positive integer as this object
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* is less than, equal to, or greater than the specified object.
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* @throws ClassCastException if the specified object's type prevents it
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* from being compared to this Object.
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*/
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public int compareTo(EntryID that) throws ClassCastException
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{
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return this.id.compareTo(that.id);
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}
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/**
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* Indicates whether some other object is "equal to" this one.
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*
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* @param that the reference object with which to compare.
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* @return <code>true</code> if this object is the same as the obj
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* argument; <code>false</code> otherwise.
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* @see #hashCode()
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* @see java.util.Hashtable
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*/
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@Override public boolean equals(Object that)
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{
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if (that == null)
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{
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return false;
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}
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if (this == that)
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{
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return true;
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}
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if (!(that instanceof EntryID))
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{
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return false;
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}
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return this.id.equals(((EntryID)that).id);
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}
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/**
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* Returns a hash code value for the object. This method is
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* supported for the benefit of hashtables such as those provided by
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* <code>java.util.Hashtable</code>.
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*
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* @return a hash code value for this object.
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* @see java.lang.Object#equals(java.lang.Object)
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* @see java.util.Hashtable
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*/
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@Override public int hashCode()
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{
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return (int)id.longValue();
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}
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/**
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* Get a string representation of this object.
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* @return A string representation of this object.
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*/
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public String toString()
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{
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return id.toString();
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}
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}
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