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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_07) on Sun May 06 17:59:49 GMT 2007 --><TITLE>ByteReplayCharSequence (Heritrix 1.12.1)</TITLE><META NAME="keywords" CONTENT="org.archive.io.ByteReplayCharSequence class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="ByteReplayCharSequence (Heritrix 1.12.1)";}</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="class-use/ByteReplayCharSequence.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </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></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../org/archive/io/BufferedSeekInputStream.html" title="class in org.archive.io"><B>PREV CLASS</B></A> <A HREF="../../../org/archive/io/CharSubSequence.html" title="class in org.archive.io"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../index.html?org/archive/io/ByteReplayCharSequence.html" target="_top"><B>FRAMES</B></A> <A HREF="ByteReplayCharSequence.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 | <A HREF="#field_summary">FIELD</A> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <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.archive.io</FONT><BR>Class ByteReplayCharSequence</H2><PRE>java.lang.Object <IMG SRC="../../../resources/inherit.gif" ALT="extended by "><B>org.archive.io.ByteReplayCharSequence</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD>java.lang.CharSequence, <A HREF="../../../org/archive/io/ReplayCharSequence.html" title="interface in org.archive.io">ReplayCharSequence</A></DD></DL><HR><DL><DT><PRE> class <B>ByteReplayCharSequence</B><DT>extends java.lang.Object<DT>implements <A HREF="../../../org/archive/io/ReplayCharSequence.html" title="interface in org.archive.io">ReplayCharSequence</A></DL></PRE><P>Provides a (Replay)CharSequence view on recorded stream bytes (a prefix buffer and overflow backing file). Treats the byte stream as 8-bit. <p>Uses a wraparound rolling buffer of the last windowSize bytes read from disk in memory; as long as the 'random access' of a CharSequence user stays within this window, access should remain fairly efficient. (So design any regexps pointed at these CharSequences to work within that range!) <p>When rereading of a location is necessary, the whole window is recentered around the location requested. (TODO: More research into whether this is the best strategy.) <p>An implementation of a ReplayCharSequence done with ByteBuffers -- one to wrap the passed prefix buffer and the second, a memory-mapped ByteBuffer view into the backing file -- was consistently slower: ~10%. My tests did the following. Made a buffer filled w/ regular content. This buffer was used as the prefix buffer. The buffer content was written MULTIPLER times to a backing file. I then did accesses w/ the following pattern: Skip forward 32 bytes, then back 16 bytes, and then read forward from byte 16-32. Repeat. Though I varied the size of the buffer to the size of the backing file,from 3-10, the difference of 10% or so seemed to persist. Same if I tried to favor get() over get(index). I used a profiler, JMP, to study times taken (St.Ack did above comment). <p>TODO determine in memory mapped files is better way to do this; probably not -- they don't offer the level of control over total memory used that this approach does.<P><P><DL><DT><B>Version:</B></DT> <DD>$Revision: 5027 $, $Date: 2007-03-29 00:30:33 +0000 (Thu, 29 Mar 2007) $</DD><DT><B>Author:</B></DT> <DD>Gordon Mohr</DD></DL><HR><P><!-- =========== FIELD SUMMARY =========== --><A NAME="field_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>Field Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#length">length</A></B></CODE><BR> Total length of character stream to replay minus the HTTP headers if present.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected static java.util.logging.Logger</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#logger">logger</A></B></CODE><BR> </TD></TR></TABLE> <!-- ======== 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/archive/io/ByteReplayCharSequence.html#ByteReplayCharSequence(byte[], long, long, java.lang.String)">ByteReplayCharSequence</A></B>(byte[] buffer, long size, long responseBodyStart, java.lang.String backingFilename)</CODE><BR> Constructor.</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> char</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#charAt(int)">charAt</A></B>(int index)</CODE><BR> Get character at passed absolute position.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#close()">close</A></B>()</CODE><BR> Cleanup resources.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#finalize()">finalize</A></B>()</CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#length()">length</A></B>()</CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.CharSequence</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#subSequence(int, int)">subSequence</A></B>(int start, int end)</CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#substring(int, int)">substring</A></B>(int offset, int len)</CODE><BR> <B>Deprecated.</B> <I>please use subSequence() and then toString() directly</I></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../org/archive/io/ByteReplayCharSequence.html#toString()">toString</A></B>()</CODE><BR> </TD></TR></TABLE> <A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TH ALIGN="left"><B>Methods inherited from class java.lang.Object</B></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE>clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait</CODE></TD></TR>?? 快捷鍵說明
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