📄 operators.htm

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD><TITLE>EL Operators</TITLE>
<LINK REL=STYLESHEET
      HREF="/el/JSP-Styles.css"
      TYPE="text/css">
</HEAD>
<BODY>
<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
  EL Operators
</TABLE>
<P>
<TABLE BORDER=1 ALIGN="CENTER">
  <TR><TH CLASS="COLORED" COLSPAN=2>Arithmetic Operators
      <TH CLASS="COLORED" COLSPAN=2>Relational Operators
  <TR><TH>Expression<TH>Result<TH>Expression<TH>Result
  <TR ALIGN="CENTER">
    <TD>\${3+2-1}<TD>${3+2-1}  <%-- Addition/Subtraction --%>
    <TD>\${1&lt;2}<TD>${1<2}      <%-- Numerical comparison --%>
  <TR ALIGN="CENTER">
    <TD>\${"1"+2}<TD>${"1"+2}     <%-- String conversion --%>
    <TD>\${"a"&lt;"b"}<TD>${"a"<"b"} <%-- Lexical comparison --%>
  <TR ALIGN="CENTER">
    <TD>\${1 + 2*3 + 3/4}<TD>${1 + 2*3 + 3/4}  <%-- Mult/Div --%>
    <TD>\${2/3 &gt;= 3/2}<TD>${2/3 >= 3/2}        <%-- >= --%>
  <TR ALIGN="CENTER">
    <TD>\${3%2}<TD>${3%2}                 <%-- Modulo --%>
    <TD>\${3/4 == 0.75}<TD>${3/4 == 0.75} <%-- Numeric = --%>
  <TR ALIGN="CENTER">
    <%-- div and mod are alternatives to / and % --%>
    <TD>\${(8 div 2) mod 3}<TD>${(8 div 2) mod 3}
    <%-- Compares with "equals" but returns false for null --%>
    <TD>\${null == "test"}<TD>${null == "test"}
      
  <TR><TH CLASS="COLORED" COLSPAN=2>Logical Operators 
      <TH CLASS="COLORED" COLSPAN=2><CODE>empty</CODE> Operator
  <TR><TH>Expression<TH>Result<TH>Expression<TH>Result
  <TR ALIGN="CENTER">
    <TD>\${(1&lt;2) && (4&lt;3)}<TD>${(1<2) && (4<3)} <%--AND--%>
    <TD>\${empty ""}<TD>${empty ""} <%-- Empty string --%>
  <TR ALIGN="CENTER">
    <TD>\${(1&lt;2) || (4&lt;3)}<TD>${(1<2) || (4<3)} <%--OR--%>
    <TD>\${empty null}<TD>${empty null} <%-- null --%>
  <TR ALIGN="CENTER">
    <TD>\${!(1&lt;2)}<TD>${!(1<2)}  <%-- NOT -%>
    <%-- Handles null or empty string in request param --%>
    <TD>\${empty param.blah}<TD>${empty param.blah}
</TABLE>
</BODY></HTML>

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