How to handle null values in Freemarker? I get some exceptions in the template when null values are present in data.
Starting from freemarker 2.3.7, you can use this syntax :
${(object.attribute)!}
or, if you want display a default text when the attribute is null :
${(object.attribute)!"default text"}
You can use the ?? test operator:
This checks if the attribute of the object is not null:
<#if object.attribute??></#if>
This checks if object or attribute is not null:
<#if (object.attribute)??></#if>
Source: FreeMarker Manual
I think it works the other way
<#if object.attribute??>
Do whatever you want....
</#if>
If object.attribute is NOT NULL, then the content will be printed.
Use ?? operator at the end of your <#if> statement.
This example demonstrates how to handle null values for two lists in a Freemaker template.
List of cars:
<#if cars??>
<#list cars as car>${car.owner};</#list>
</#if>
List of motocycles:
<#if motocycles??>
<#list motocycles as motocycle>${motocycle.owner};</#list>
</#if>
I would like to add more context if you have issues and this is what I have tried.
<#if Recipient.account_type?has_content>
… (executes if variable exists)
<#else>
… (executes if variable does not exist)
</#if>
This is more like Javascript IF and ELSE concept where we want to check whether this value or another chaining through required logic.
Freemarker webite
Other reference:
Scenario: Customer has ID and name combined like 13242 Harish, so where our stakeholder need the only name, so I have tried this ${record.entity?keep_after(" ")} and it did work, however, it can only work when you have space, but when a customer doesn't have space and one name, I had to do some IF ELSE condition to check Null value.
Use:
${(user.isSuperman!false)?c}
It will work when "isSuperman" is null and when have boolean value
What we want:
For "null" we want to output 'false'
For boolean value and want to output value ('true' or 'false')
What we know:
boolean need to convert to string by using "?c" see Built-ins for booleans
but null we cannot convert to string and we need to use "!" see Handling missing values
Related
For example.
String s can have these values like "value", "" or null.
<#if str?? && str?has_content>
${str}
</#if>
Can I check ??(null) and ?has_content(empty not null) both value in freemarker if statement not using TemplateModel?
str?has_content returns true if str is non-null (non-missing), and is also not a 0-length string. So you just need <#if str?has_content>.
(As of TemplateModel-s, every value is a TemplateModel as far as templates see. There's no such thing as a non-TemplateModel value.)
I'm trying to compare two values
<#if user.cellPhone != changedUser.cellPhon>
<br><span class="changes">*${changedUser.cellPhone}</span></#if>
I'm getting an error
freemarker.core.InvalidReferenceException: The following has evaluated to null or missing:==> changeUser
Tip:
If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
Add null check to condition changedUser??:
<#if changedUser?? && user.cellPhone != changedUser.cellPhon>
<#list reports as report>
<#list report.transactionList as expense>
${expense.transactionID}^<#t>
${table[expenses.transcationID}
<#if expense.modifiedCreated?has_content>
${expense.modifiedCreated}^<#t>
<#else>
${expense.created}^<#t>
</#if>
In the above code I have a hash table called table and I want to use expense.transactionID as the key to then load the table's value like in the above code.
when I run it, the second item instead of a value is just a blank spot.
figured it out. {table[expenses.transcationID} needs to cast the category I am using as the key into a string. so the answer is: {table[expenses.transcationID?string}
I'm having trouble while trying to assign value to a variable using Freemarker.
<#if size??>
<#assign num=size?number>
<#if (num>0)>
<#list 0..num-1 as i>
<#if .vars['abc'+i?c] = "test">
<#assign .vars['abc'+i?c] = .vars['abc'+i?c]?replace("test","Test")>
</#if>
</#list>
</#if>
This is the error message: Encountered ".", but was expecting one of:
STRING_LITERAL
RAW_STRING
ID
Can anyone help me with this?
Thank you.
You can only write top-level variables in a FreeMarker template. Also you can't assign to a variable with dynamically constructed name, except with an ?interpret hack: <#"<#assign abc${i?c} = abc${i?c}?reaplce('test', "Test")>"?interpret />. Obviously that's horrid... BTW, what's the use case here? Why do you need to assign to dynamically constructed variable names?
Is it possible to write this in freemarker.
<input type="checkbox" value="Available ?" checked="<#if ${status}=='Available'>true<#else>false</#if>"/>
For now it throws exception
I want html checkbox to be checked if status property equals to "Available".
How to do this in freemarker?
<#if ${status}=='Available'> has a syntactical error (that the error message that you haven't included points to, I'm certain): you can't use ${...} inside FreeMarker tags (well, except inside string literals, but whatever). It should be just <#if status == 'Available'>. But, the simples solution for what you want is:
checked="${(status == 'Available')?c}"
or if you have an older FreeMarker then:
checked="${(status == 'Available')?string('true', 'false')}"