Update equals() method code generation to use pattern matching

Answered

Is there a way to change the default template of java.util.Objects.equals and hashCode (java 7+) to use pattern matching every time it generates the code? As it stands right now, the IDE tells me that the code can be shortened by using pattern matching. I do not know how to reformat the code to create my own template.

7 comments
Comment actions Permalink

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

0
Comment actions Permalink

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);
}
0
Comment actions Permalink

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

0
Comment actions Permalink

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.

0
Comment actions Permalink

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
;
}

 

1
Comment actions Permalink

It seems to work. Thanks a lot!

0
Comment actions Permalink

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

0

Please sign in to leave a comment.