<!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 1.4.2_16) on Fri Nov 19 12:15:44 PST 2010 --> <TITLE> CharStream (Velocity 1.7 API) </TITLE> <META NAME="keywords" CONTENT="org.apache.velocity.runtime.parser.CharStream interface"> <LINK REL ="stylesheet" TYPE="text/css" HREF="../../../../../stylesheet.css" TITLE="Style"> <SCRIPT type="text/javascript"> function windowTitle() { parent.document.title="CharStream (Velocity 1.7 API)"; } </SCRIPT> </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=3 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/CharStream.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"> PREV CLASS <A HREF="../../../../../org/apache/velocity/runtime/parser/ParserConstants.html" title="interface in org.apache.velocity.runtime.parser"><B>NEXT CLASS</B></A></FONT></TD> <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../index.html" target="_top"><B>FRAMES</B></A> <A HREF="CharStream.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 | CONSTR | <A HREF="#method_summary">METHOD</A></FONT></TD> <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> DETAIL: FIELD | CONSTR | <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.apache.velocity.runtime.parser</FONT> <BR> Interface CharStream</H2> <DL> <DT><B>All Known Implementing Classes:</B> <DD><A HREF="../../../../../org/apache/velocity/runtime/parser/VelocityCharStream.html" title="class in org.apache.velocity.runtime.parser">VelocityCharStream</A></DD> </DL> <HR> <DL> <DT>public interface <B>CharStream</B></DL> <P> This interface describes a character stream that maintains line and column number positions of the characters. It also has the capability to backup the stream to some extent. An implementation of this interface is used in the TokenManager implementation generated by JavaCCParser. All the methods except backup can be implemented in any fashion. backup needs to be implemented correctly for the correct operation of the lexer. Rest of the methods are all used to get information like line number, column number and the String that constitutes a token and are not used by the lexer. Hence their implementation won't affect the generated lexer's operation. <P> <P> <HR> <P> <!-- ======== NESTED CLASS SUMMARY ======== --> <!-- =========== FIELD SUMMARY =========== --> <!-- ======== CONSTRUCTOR SUMMARY ======== --> <!-- ========== METHOD SUMMARY =========== --> <A NAME="method_summary"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TD COLSPAN=2><FONT SIZE="+2"> <B>Method Summary</B></FONT></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/apache/velocity/runtime/parser/CharStream.html#backup(int)">backup</A></B>(int amount)</CODE> <BR> Backs up the input stream by amount steps.</TD> </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/apache/velocity/runtime/parser/CharStream.html#BeginToken()">BeginToken</A></B>()</CODE> <BR> Returns the next character that marks the beginning of the next token.</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/apache/velocity/runtime/parser/CharStream.html#Done()">Done</A></B>()</CODE> <BR> The lexer calls this function to indicate that it is done with the stream and hence implementations can free any resources held by this class.</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/apache/velocity/runtime/parser/CharStream.html#getBeginColumn()">getBeginColumn</A></B>()</CODE> <BR> Returns the column number of the first character for current token (being matched after the last call to BeginTOken).</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/apache/velocity/runtime/parser/CharStream.html#getBeginLine()">getBeginLine</A></B>()</CODE> <BR> Returns the line number of the first character for current token (being matched after the last call to BeginTOken).</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/apache/velocity/runtime/parser/CharStream.html#getColumn()">getColumn</A></B>()</CODE> <BR> <B>Deprecated.</B> <I></I> </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/apache/velocity/runtime/parser/CharStream.html#getEndColumn()">getEndColumn</A></B>()</CODE> <BR> Returns the column number of the last character for current token (being matched after the last call to BeginTOken).</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/apache/velocity/runtime/parser/CharStream.html#getEndLine()">getEndLine</A></B>()</CODE> <BR> Returns the line number of the last character for current token (being matched after the last call to BeginTOken).</TD> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"> <CODE> <A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A></CODE></FONT></TD> <TD><CODE><B><A HREF="../../../../../org/apache/velocity/runtime/parser/CharStream.html#GetImage()">GetImage</A></B>()</CODE> <BR> Returns a string made up of characters from the marked token beginning to the current buffer position.</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/apache/velocity/runtime/parser/CharStream.html#getLine()">getLine</A></B>()</CODE> <BR> <B>Deprecated.</B> <I></I> </TD> </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/apache/velocity/runtime/parser/CharStream.html#GetSuffix(int)">GetSuffix</A></B>(int len)</CODE> <BR> Returns an array of characters that make up the suffix of length 'len' for the currently matched token.</TD> </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/apache/velocity/runtime/parser/CharStream.html#readChar()">readChar</A></B>()</CODE> <BR> Returns the next character from the selected input.</TD> </TR> </TABLE> <P> <!-- ============ FIELD DETAIL =========== --> <!-- ========= CONSTRUCTOR DETAIL ======== --> <!-- ============ METHOD DETAIL ========== --> <A NAME="method_detail"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TD COLSPAN=1><FONT SIZE="+2"> <B>Method Detail</B></FONT></TD> </TR> </TABLE> <A NAME="readChar()"><!-- --></A><H3> readChar</H3> <PRE> public char <B>readChar</B>() throws <A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE> <DL> <DD>Returns the next character from the selected input. The method of selecting the input is the responsibility of the class implementing this interface. Can throw any java.io.IOException. <P> <DD><DL> <DT><B>Throws:</B> <DD><CODE><A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL> </DD> </DL> <HR> <A NAME="getColumn()"><!-- --></A><H3> getColumn</H3> <PRE> public int <B>getColumn</B>()</PRE> <DL> <DD><B>Deprecated.</B> <I></I> <P> <DD>Returns the column position of the character last read. <P> <DD><DL> <DT><B>See Also:</B><DD><A HREF="../../../../../org/apache/velocity/runtime/parser/CharStream.html#getEndColumn()"><CODE>getEndColumn()</CODE></A></DL> </DD> </DL> <HR> <A NAME="getLine()"><!-- --></A><H3> getLine</H3> <PRE> public int <B>getLine</B>()</PRE> <DL> <DD><B>Deprecated.</B> <I></I> <P> <DD>Returns the line number of the character last read. <P> <DD><DL> <DT><B>See Also:</B><DD><A HREF="../../../../../org/apache/velocity/runtime/parser/CharStream.html#getEndLine()"><CODE>getEndLine()</CODE></A></DL> </DD> </DL> <HR> <A NAME="getEndColumn()"><!-- --></A><H3> getEndColumn</H3> <PRE> public int <B>getEndColumn</B>()</PRE> <DL> <DD>Returns the column number of the last character for current token (being matched after the last call to BeginTOken). <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="getEndLine()"><!-- --></A><H3> getEndLine</H3> <PRE> public int <B>getEndLine</B>()</PRE> <DL> <DD>Returns the line number of the last character for current token (being matched after the last call to BeginTOken). <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="getBeginColumn()"><!-- --></A><H3> getBeginColumn</H3> <PRE> public int <B>getBeginColumn</B>()</PRE> <DL> <DD>Returns the column number of the first character for current token (being matched after the last call to BeginTOken). <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="getBeginLine()"><!-- --></A><H3> getBeginLine</H3> <PRE> public int <B>getBeginLine</B>()</PRE> <DL> <DD>Returns the line number of the first character for current token (being matched after the last call to BeginTOken). <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="backup(int)"><!-- --></A><H3> backup</H3> <PRE> public void <B>backup</B>(int amount)</PRE> <DL> <DD>Backs up the input stream by amount steps. Lexer calls this method if it had already read some characters, but could not use them to match a (longer) token. So, they will be used again as the prefix of the next token and it is the implemetation's responsibility to do this right. <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="BeginToken()"><!-- --></A><H3> BeginToken</H3> <PRE> public char <B>BeginToken</B>() throws <A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE> <DL> <DD>Returns the next character that marks the beginning of the next token. All characters must remain in the buffer between two successive calls to this method to implement backup correctly. <P> <DD><DL> <DT><B>Throws:</B> <DD><CODE><A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL> </DD> </DL> <HR> <A NAME="GetImage()"><!-- --></A><H3> GetImage</H3> <PRE> public <A HREF="http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>GetImage</B>()</PRE> <DL> <DD>Returns a string made up of characters from the marked token beginning to the current buffer position. Implementations have the choice of returning anything that they want to. For example, for efficiency, one might decide to just return null, which is a valid implementation. <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="GetSuffix(int)"><!-- --></A><H3> GetSuffix</H3> <PRE> public char[] <B>GetSuffix</B>(int len)</PRE> <DL> <DD>Returns an array of characters that make up the suffix of length 'len' for the currently matched token. This is used to build up the matched string for use in actions in the case of MORE. A simple and inefficient implementation of this is as follows : { String t = GetImage(); return t.substring(t.length() - len, t.length()).toCharArray(); } <P> <DD><DL> </DL> </DD> </DL> <HR> <A NAME="Done()"><!-- --></A><H3> Done</H3> <PRE> public void <B>Done</B>()</PRE> <DL> <DD>The lexer calls this function to indicate that it is done with the stream and hence implementations can free any resources held by this class. 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