Allow Batch Field Encapsulation for Multiple Fields

[HeikoKlare]

Issue: eclipse-jdt/eclipse.jdt.ui#1080

Current Situation

JDT provides two functionalities for the generation of getters and setters.

1. Apply the Encapsulate Field refactoring, which generates getters and setters and, in particular, allows to replace references to the field with calls of the generated accessors.
   
2. Apply the Generate Getters/Setters source modification, which allows to add getters and setters to the file.
   

While getter/setter generation can be applied in a batch operation for multiple fields of a class, the refactoring can only be applied to a single field at once.

Expected Behavior

The user shall be able to perform a getter/setter generation together with field encapsulation (i.e., replacement of field access with calls of accessors) in batch mode to multiple fields of a class.

Proposed Solution

Starting from the two existing functionalities, either the getter/setter generation may be extended by functionality to encapsulate the fields, or the field encapsulation refactoring may be enhanced with support for being applied to multiple fields as once.

I propose to follow to second approach, as performing field encapsulation actually is a refactoring that goes beyond source manipulation. I.e., in addition (or as a replacement for the) to the existing Encapsulate Field refactoring, an Encapsulate Fields refactoring should be provided. As a result, the options provided by getter/setter generation and field encapsulation should be aligned. The new refactoring should be capable of everything provided by the existing refactoring but along with a selection of all fiels to apply it to, i.e. :

• Selecting the fields to encapsulate (in case of a text selection or when triggered as a quick fix, may be restricted to the fields in the text selection)
• Per field:
  • Defining wheter a getter and/or setter shall be created along with their names
  • A selection where the method(s) shall be placed