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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.5.0_15) on Thu Aug 28 21:12:39 PDT 2008 --><TITLE>SequenceManager (Openfire 3.6.0a Javadoc)</TITLE><META NAME="keywords" CONTENT="org.jivesoftware.database.SequenceManager class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="SequenceManager (Openfire 3.6.0a Javadoc)";}</SCRIPT><NOSCRIPT></NOSCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Openfire 3.6.0a Javadoc</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../org/jivesoftware/database/SchemaManager.html" title="class in org.jivesoftware.database"><B>PREV CLASS</B></A> NEXT CLASS</FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../index.html?org/jivesoftware/database/SequenceManager.html" target="_top"><B>FRAMES</B></A> <A HREF="SequenceManager.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">org.jivesoftware.database</FONT><BR>Class SequenceManager</H2><PRE><A HREF="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Object.html" title="class or interface in java.lang">java.lang.Object</A> <IMG SRC="../../../resources/inherit.gif" ALT="extended by "><B>org.jivesoftware.database.SequenceManager</B></PRE><HR><DL><DT><PRE>public class <B>SequenceManager</B><DT>extends <A HREF="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A></DL></PRE><P>Manages sequences of unique ID's that get stored in the database. Database support for sequences varies widely; some don't use them at all. Instead, we handle unique ID generation with a combination VM/database solution.<p/> A special table in the database doles out blocks of unique ID's to each virtual machine that interacts with Jive. This has the following consequences: <ul> <li>There is no need to go to the database every time we want a new unique id. <li>Multiple app servers can interact with the same db without id collision. <li>The order of unique id's may not correspond to the creation date of objects. <li>There can be gaps in ID's after server restarts since blocks will get "lost" if the block size is greater than 1. </ul><p/> Each sequence type that this class manages has a different block size value. Objects that aren't created often have a block size of 1, while frequently created objects such as entries and comments have larger block sizes.<P><P><DL><DT><B>Author:</B></DT> <DD>Matt Tucker, Bruce Ritchie</DD></DL><HR><P><!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../../org/jivesoftware/database/SequenceManager.html#SequenceManager(int, int)">SequenceManager</A></B>(int seqType, int size)</CODE><BR> Creates a new DbSequenceManager.</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Method Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static long</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/jivesoftware/database/SequenceManager.html#nextID(int)">nextID</A></B>(int type)</CODE><BR> Returns the next ID of the specified type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static long</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/jivesoftware/database/SequenceManager.html#nextID(java.lang.Object)">nextID</A></B>(<A HREF="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A> o)</CODE><BR> Returns the next id for an object that has defined the annotation <A HREF="../../../org/jivesoftware/database/JiveID.html" title="annotation in org.jivesoftware.database"><CODE>JiveID</CODE></A>.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> long</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/jivesoftware/database/SequenceManager.html#nextUniqueID()">nextUniqueID</A></B>()</CODE><BR> Returns the next available unique ID.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/jivesoftware/database/SequenceManager.html#setBlockSize(int, int)">setBlockSize</A></B>(int type, int blockSize)</CODE>⌨️ 快捷键说明
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