Intellij template generator syntax

Question

In Intellij IDE you can writte your own templates for generating code. I would like to writte a template for generating my equals method. The goal is to have a equals method that do not distiguish between null and a empty string like this:
(using StringUtils.IsNotEmpty from apache.commons.language)

public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    POJO pojo = (POJO) o;

    if(StringUtils.IsNotEmpty(stringAtt) ? !stringAtt.equals(pojo.stringAtt) : StringUtils.IsNotEmpty(pojo.stringAtt)) return false;

    return true;       
}

I would like to writte this equals as a template so I can generate code for all the POJOs I am using.

The problem is that I do not fully understand the syntax of language and tokens used for intellij template generation. It looks like this:

#parse("equalsHelper.vm")
public boolean equals(##
#if ($settings.generateFinalParameters)
  final ##
#end
Object $paramName){
#addEqualsPrologue()
#if ($fields.size() > 0)
  #addClassInstance()
#foreach($field in $fields)     
  #addFieldComparison($field)
#end
#end

return true;
}
##
#macro(addFieldComparison $field)
  #if ($field.notNull)
    if(!${field.accessor}.equals(${classInstanceName}.$field.accessor))return false;
  #else
    if($field.accessor != null ? !${field.accessor}.equals(${classInstanceName}.$field.accessor) : ${classInstanceName}.$field.accessor != null)return false;
  #end
#end
##

I have looked for it on Intellij doc pages but I cant find a explanation for the syntax.

Could someone give me a good example or point to some documentation webpage so I can learn how to do it?
Or what language is this so I can learn it by myself

Thanks.

user_1861742 · Answer

So the language used for this is Velocity Template Language or VTL

I think I have the job done. The only important thing was to check if the POJO´s field is a String. Then if it is writte the code straigth foward. This is my answer I hope it helps, I´m only giving the code for the addFieldComparisson macro, the rest is the same:

#macro(addFieldComparison $field)
  ## Check if the field is a String
  // CHECKED TYPE: ${field.accessor.class.name}
  #if (${field.accessor.class.name} == "java.lang.String")
    //is a String
    if(StringUtils.isNotEmpty($field.accessor) ? !${field.accessor}.equals(${classInstanceName}.$field.accessor) : StringUtils.isNotEmpty(${classInstanceName}.$field.accessor))return false;
  #else
    // Not a String
    if($field.accessor != null ? !${field.accessor}.equals(${classInstanceName}.$field.accessor) : ${classInstanceName}.$field.accessor != null)return false;
  #end
#end

Intellij template generator syntax

1 Answers