Update equals() method code generation to use pattern matching

Hello - could you describe what you would like to achieve in more detail using an example?

Certainly.

This is what the equals() method before pattern matching existed and what the IDE generates by default:

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof Employee)) return false;
    Employee employee = (Employee) o;
    return id == employee.id && Objects.equals(name, employee.name);
}

After pattern switching though and what I want the IDE to always use when generating equals method is:

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof Employee employee)) return false;
    return id == employee.id && Objects.equals(name, employee.name);
}

You can change the default template - in the Generate popup, click equals() and hashCode(), then click to open the Templates dialog, where you can create a custom template based on a default one. Check https://www.jetbrains.com/help/idea/generating-code.html#customize-templates for the details

Yes but do you think you could directly tell me what the new code would look like? I think it would be a very small code change.

Kanishknishar

e.g. you can try this template:

#parse("equalsHelper.vm")
public boolean equals(##
#if ($settings.generateFinalParameters)
  final ##
#end
Object $paramName){
  if(this == $paramName) return true;
  if(!($paramName instanceof $classname ${classInstanceName})) return false;
  #if ($superHasEquals)
    if(!super.equals($paramName)) return false;
  #end
  return ##
   #set($i = 0)
   #foreach($field in $fields)
     #if ($i > 0)
     && ##
     #end
     #set($i = $i + 1)
     #if ($field.primitive)
       #if ($field.double || $field.float)
         #addDoubleFieldComparisonConditionDirect($field) ##
       #else
         #addPrimitiveFieldComparisonConditionDirect($field) ##
       #end
     #elseif ($field.enum)
       #addPrimitiveFieldComparisonConditionDirect($field) ##
     #elseif ($field.array)
java.util.Arrays.equals($field.accessor, ${classInstanceName}.$field.accessor)##
     #elseif ($field.notNull)
${field.accessor}.equals(${classInstanceName}.$field.accessor)##
     #else
java.util.Objects.equals($field.accessor, ${classInstanceName}.$field.accessor)##
     #end
   #end
  ;
}

It seems to work. Thanks a lot!

and just in case: you can see the following code in the original template in IDEA:

#parse("equalsHelper.vm")
...
  #addEqualsPrologue()
  #addClassInstance()

This refers to https://github.com/JetBrains/intellij-community/blob/master/java/java-impl/src/com/intellij/codeInsight/generation/equalsHelper.vm, lines 26 and 4
You can use it as an example how you can modify the template