test attribute in JSTL c if tag

Question

I saw some code like the following in a JSP   lt c if test   lt   request isUserInRole RoleEnum USER getCode     gt   gt       lt li gt user lt  li gt   lt  c if gt    My confusion is over the     that appears in the value of the test attribute  My understanding was that anything included within  lt      gt  is printed to the output  but surely the value assigned to test must be a Boolean  so why does this work   For bonus points  is there any way to change the attribute value above such that it does not use scriptlet code  Presumably  that means using EL instead   Cheers  Don

User · Answer

The expression between the  lt       is evaluated before the c if tag is evaluated  So  supposing that  request isUserInRole  returns  true   your example would be evaluated to this first    lt c if test  true  gt       lt li gt user lt  li gt   lt  c if gt    and then the c if tag would be executed

User · Answer

lt      by itself will be sent to the output  in the context of the JSTL it will be evaluated to a string

User · Answer

The expression between the  lt       is evaluated before the c if tag is evaluated  So  supposing that  request isUserInRole  returns  true   your example would be evaluated to this first    lt c if test  true  gt       lt li gt user lt  li gt   lt  c if gt    and then the c if tag would be executed

User · Answer

All that the test attribute looks for to determine if something is true is the string  true   case in-sensitive    For example  the following code will print  Hello world     lt c if test  true  gt Hello world  lt  c if gt    The code within the  lt      gt  returns a boolean  so it will either print the string  true  or  false   which is exactly what the  lt c if gt  tag looks for

User · Answer

The expression between the  lt       is evaluated before the c if tag is evaluated  So  supposing that  request isUserInRole  returns  true   your example would be evaluated to this first    lt c if test  true  gt       lt li gt user lt  li gt   lt  c if gt    and then the c if tag would be executed

User · Answer

The expression between the  lt       is evaluated before the c if tag is evaluated  So  supposing that  request isUserInRole  returns  true   your example would be evaluated to this first    lt c if test  true  gt       lt li gt user lt  li gt   lt  c if gt    and then the c if tag would be executed

User · Answer

You can also use something like    lt c if test     testObject testPropert     testValue     gt     lt  c if gt

User · Answer

lt      by itself will be sent to the output  in the context of the JSTL it will be evaluated to a string

User · Answer

All that the test attribute looks for to determine if something is true is the string  true   case in-sensitive    For example  the following code will print  Hello world     lt c if test  true  gt Hello world  lt  c if gt    The code within the  lt      gt  returns a boolean  so it will either print the string  true  or  false   which is exactly what the  lt c if gt  tag looks for

User · Answer

Attributes in JSP tag libraries in general can be either static or resolved at request time   If they are resolved at request time the JSP will resolve their value at runtime and pass the output on to the tag   This means you can put pretty much any JSP code into the attribute and the tag will behave accordingly to what output that produces   If you look at the jstl taglib docs you can see which attributes are reuest time and which are not  http   java sun com products jsp jstl 1 1 docs tlddocs index html

User · Answer

lt      by itself will be sent to the output  in the context of the JSTL it will be evaluated to a string

User · Answer

Attributes in JSP tag libraries in general can be either static or resolved at request time   If they are resolved at request time the JSP will resolve their value at runtime and pass the output on to the tag   This means you can put pretty much any JSP code into the attribute and the tag will behave accordingly to what output that produces   If you look at the jstl taglib docs you can see which attributes are reuest time and which are not  http   java sun com products jsp jstl 1 1 docs tlddocs index html

User · Answer

Attributes in JSP tag libraries in general can be either static or resolved at request time   If they are resolved at request time the JSP will resolve their value at runtime and pass the output on to the tag   This means you can put pretty much any JSP code into the attribute and the tag will behave accordingly to what output that produces   If you look at the jstl taglib docs you can see which attributes are reuest time and which are not  http   java sun com products jsp jstl 1 1 docs tlddocs index html

User · Answer

All that the test attribute looks for to determine if something is true is the string  true   case in-sensitive    For example  the following code will print  Hello world     lt c if test  true  gt Hello world  lt  c if gt    The code within the  lt      gt  returns a boolean  so it will either print the string  true  or  false   which is exactly what the  lt c if gt  tag looks for

User · Answer

You can also use something like    lt c if test     testObject testPropert     testValue     gt     lt  c if gt

User · Answer

You can also use something like    lt c if test     testObject testPropert     testValue     gt     lt  c if gt

User · Answer

All that the test attribute looks for to determine if something is true is the string  true   case in-sensitive    For example  the following code will print  Hello world     lt c if test  true  gt Hello world  lt  c if gt    The code within the  lt      gt  returns a boolean  so it will either print the string  true  or  false   which is exactly what the  lt c if gt  tag looks for

User · Answer

lt      by itself will be sent to the output  in the context of the JSTL it will be evaluated to a string

User · Answer

Attributes in JSP tag libraries in general can be either static or resolved at request time   If they are resolved at request time the JSP will resolve their value at runtime and pass the output on to the tag   This means you can put pretty much any JSP code into the attribute and the tag will behave accordingly to what output that produces   If you look at the jstl taglib docs you can see which attributes are reuest time and which are not  http   java sun com products jsp jstl 1 1 docs tlddocs index html

User · Answer

You can also use something like    lt c if test     testObject testPropert     testValue     gt     lt  c if gt

[java] test attribute in JSTL <c:if> tag

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