expressionevaluator.html

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Evaluates an expression.  </TD>
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<CODE>abstract &nbsp;<A HREF="../../../../javax/servlet/jsp/el/Expression.html" title="class in javax.servlet.jsp.el">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../javax/servlet/jsp/el/ExpressionEvaluator.html#parseExpression(java.lang.String, java.lang.Class, javax.servlet.jsp.el.FunctionMapper)">parseExpression</A></B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;expression,
                <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Class.html" title="class or interface in java.lang">Class</A>&nbsp;expectedType,
                <A HREF="../../../../javax/servlet/jsp/el/FunctionMapper.html" title="interface in javax.servlet.jsp.el">FunctionMapper</A>&nbsp;fMapper)</CODE>

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prepare an expression for later evaluation.  </TD>
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<TD><B>Methods inherited from class java.lang.<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A></B></TD>
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<A NAME="ExpressionEvaluator()"><!-- --></A><H3>
ExpressionEvaluator</H3>
<PRE>
public <B>ExpressionEvaluator</B>()</PRE>
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<A NAME="parseExpression(java.lang.String, java.lang.Class, javax.servlet.jsp.el.FunctionMapper)"><!-- --></A><H3>
parseExpression</H3>
<PRE>
public abstract <A HREF="../../../../javax/servlet/jsp/el/Expression.html" title="class in javax.servlet.jsp.el">Expression</A> <B>parseExpression</B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;expression,
                                           <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Class.html" title="class or interface in java.lang">Class</A>&nbsp;expectedType,
                                           <A HREF="../../../../javax/servlet/jsp/el/FunctionMapper.html" title="interface in javax.servlet.jsp.el">FunctionMapper</A>&nbsp;fMapper)
                                    throws <A HREF="../../../../javax/servlet/jsp/el/ELException.html" title="class in javax.servlet.jsp.el">ELException</A></PRE>
<DL>
<DD>Prepare an expression for later evaluation.  This method should perform
 syntactic validation of the expression; if in doing so it detects 
 errors, it should raise an ELParseException.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>expression</CODE> - The expression to be evaluated.<DD><CODE>expectedType</CODE> - The expected type of the result of the evaluation<DD><CODE>fMapper</CODE> - A FunctionMapper to resolve functions found in 
     the expression.  It can be null, in which case no functions 
     are supported for this invocation.  The ExpressionEvaluator 
     must not hold on to the FunctionMapper reference after 
     returning from <code>parseExpression()</code>.  The 
     <code>Expression</code> object returned must invoke the same 
     functions regardless of whether the mappings in the 
     provided <code>FunctionMapper</code> instance change between 
     calling <code>ExpressionEvaluator.parseExpression()</code>
     and <code>Expression.evaluate()</code>.
<DT><B>Returns:</B><DD>The Expression object encapsulating the arguments.
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../javax/servlet/jsp/el/ELException.html" title="class in javax.servlet.jsp.el">ELException</A></CODE> - Thrown if parsing errors were found.</DL>
</DD>
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<A NAME="evaluate(java.lang.String, java.lang.Class, javax.servlet.jsp.el.VariableResolver, javax.servlet.jsp.el.FunctionMapper)"><!-- --></A><H3>
evaluate</H3>
<PRE>
public abstract <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A> <B>evaluate</B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;expression,
                                <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Class.html" title="class or interface in java.lang">Class</A>&nbsp;expectedType,
                                <A HREF="../../../../javax/servlet/jsp/el/VariableResolver.html" title="interface in javax.servlet.jsp.el">VariableResolver</A>&nbsp;vResolver,
                                <A HREF="../../../../javax/servlet/jsp/el/FunctionMapper.html" title="interface in javax.servlet.jsp.el">FunctionMapper</A>&nbsp;fMapper)
                         throws <A HREF="../../../../javax/servlet/jsp/el/ELException.html" title="class in javax.servlet.jsp.el">ELException</A></PRE>
<DL>
<DD>Evaluates an expression.  This method may perform some syntactic 
 validation and, if so, it should raise an ELParseException error if 
 it encounters syntactic errors.  EL evaluation errors should cause 
 an ELException to be raised.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>expression</CODE> - The expression to be evaluated.<DD><CODE>expectedType</CODE> - The expected type of the result of the evaluation<DD><CODE>vResolver</CODE> - A VariableResolver instance that can be used at 
     runtime to resolve the name of implicit objects into Objects.<DD><CODE>fMapper</CODE> - A FunctionMapper to resolve functions found in 
     the expression.  It can be null, in which case no functions 
     are supported for this invocation.
<DT><B>Returns:</B><DD>The result of the expression evaluation.
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../javax/servlet/jsp/el/ELException.html" title="class in javax.servlet.jsp.el">ELException</A></CODE> - Thrown if the expression evaluation failed.</DL>
</DD>
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