Operators"

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EL expressions provide the following operators<ref>The information is from [http://download.oracle.com/javaee/1.4/tutorial/doc/JSPIntro7.html JSP Tutorial].</ref>:
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{| class='wikitable'
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! Type !! Operators !! Description
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|-
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| Arithmetic
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| +, -<ref>binary</ref>, *, /, div, %, mod, -<ref>unary</ref>
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|
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* / and div are the same, while % and mod are the same.
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|-
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| Logical
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| and, <nowiki>&&</nowiki>, or, <nowiki>||</nowiki>, not, !, empty
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|
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* The empty operator is a prefix operation that can be used to determine whether a value is null or empty, such as ${empty foo}.
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|-
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| Relational
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|  ==, eq, !=, ne, <, lt, >, gt, <=, ge, >=, le
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|
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* Comparisons can be made against other values, or against boolean, string, integer, or floating point literals.
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|-
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| Conditional
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| A ? B : C
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| It evaluate B or C, depending on the result of the evaluation of A.
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|-
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| Index
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| []
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|
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To evaluate expr-a[expr-b], evaluate expr-a into value-a and evaluate expr-b into value-b. If either value-a or value-b is null, return null.
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* If value-a is a Map, return value-a.get(value-b). If !value-a.containsKey(value-b), then return null.
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* If value-a is a List or array, coerce value-b to int and return value-a.get(value-b) or Array.get(value-a, value-b), as appropriate. If the coercion couldn't be performed, an error is returned. If the get call returns an IndexOutOfBoundsException, null is returned. If the get call returns another exception, an error is returned.
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* If value-a is a JavaBeans object, coerce value-b to String. If value-b is a readable property of value-a, then return the result of a get call. If the get method throws an exception, an error is returned.
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|-
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| Member
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| .
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|
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* Properties of variables are accessed using the . operator and can be nested arbitrarily.
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* The value of a map can be accessed by using the . operator.
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|}
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<blockquote>
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----
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<references/>
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</blockquote>
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The relative precedence levels of operators from the highest to lowest, left to right are as follows:
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* [] .
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* ()<ref>Used to change the precedence of operators.</ref>
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* - <ref>unary</ref> not ! empty
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* * / div % mod
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* + - <ref>binary</ref>
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* < > <= >= lt gt le ge
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* == != eq ne
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* && and
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* || or
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* ? :
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<blockquote>
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----
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<references/>
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</blockquote>
  
 
=Version History=
 
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Latest revision as of 09:41, 1 June 2022


DocumentationZUML ReferenceEL ExpressionsOperators
Operators


EL expressions provide the following operators[1]:

Type Operators Description
Arithmetic +, -[2], *, /, div, %, mod, -[3]
  • / and div are the same, while % and mod are the same.
Logical and, &&, or, ||, not, !, empty
  • The empty operator is a prefix operation that can be used to determine whether a value is null or empty, such as ${empty foo}.
Relational ==, eq, !=, ne, <, lt, >, gt, <=, ge, >=, le
  • Comparisons can be made against other values, or against boolean, string, integer, or floating point literals.
Conditional A ? B : C It evaluate B or C, depending on the result of the evaluation of A.
Index []

To evaluate expr-a[expr-b], evaluate expr-a into value-a and evaluate expr-b into value-b. If either value-a or value-b is null, return null.

  • If value-a is a Map, return value-a.get(value-b). If !value-a.containsKey(value-b), then return null.
  • If value-a is a List or array, coerce value-b to int and return value-a.get(value-b) or Array.get(value-a, value-b), as appropriate. If the coercion couldn't be performed, an error is returned. If the get call returns an IndexOutOfBoundsException, null is returned. If the get call returns another exception, an error is returned.
  • If value-a is a JavaBeans object, coerce value-b to String. If value-b is a readable property of value-a, then return the result of a get call. If the get method throws an exception, an error is returned.
Member .
  • Properties of variables are accessed using the . operator and can be nested arbitrarily.
  • The value of a map can be accessed by using the . operator.
  1. ↑ The information is from JSP Tutorial.
  2. ↑ binary
  3. ↑ unary

The relative precedence levels of operators from the highest to lowest, left to right are as follows:

  • [] .
  • ()[1]
  • - [2] not ! empty
  • * / div % mod
  • + - [3]
  • < > <= >= lt gt le ge
  • == != eq ne
  • && and
  • || or
  • ? :
  1. ↑ Used to change the precedence of operators.
  2. ↑ unary
  3. ↑ binary

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Last Update : 2022/06/01


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Last Update : 2022/06/01

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