Module java4ever.binding
Package tech.deplant.java4ever.binding.generator.javapoet

Class NameAllocator

java.lang.Object
tech.deplant.java4ever.binding.generator.javapoet.NameAllocator
All Implemented Interfaces:
Cloneable
public final class NameAllocator extends Object implements Cloneable
Assigns Java identifier names to avoid collisions, keywords, and invalid characters. To use, first create an instance and allocate all of the names that you need. Typically this is a mix of user-supplied names and constants: 
   

   NameAllocator nameAllocator = new NameAllocator();
   for (MyProperty property : properties) {
     nameAllocator.newName(property.parameterName(), property);
   }
   nameAllocator.newName("sb", "string builder");

Pass a unique tag object to each allocation. The tag scopes the parameterName, and can be used to look up the allocated parameterName later. Typically the tag is the object that is being named. In the above example we use property for the user-supplied property names, and "string builder" for our constant string builder.

Once we've allocated names we can use them when generating code: 

   

   MethodSpec.Builder builder = MethodSpec.methodBuilder("toString")
       .addAnnotation(Override.class)
       .addModifiers(Modifier.PUBLIC)
       .returns(String.class);

   builder.addStatement("$1T $2N = new $1T()",
       StringBuilder.class, nameAllocator.get("string builder"));
   for (MyProperty property : properties) {
     builder.addStatement("$N.append($N)",
         nameAllocator.get("string builder"), nameAllocator.get(property));
   }
   builder.addStatement("return $N", nameAllocator.get("string builder"));
   return builder.build();

The above code generates unique names if presented with conflicts. Given user-supplied properties with names ab and sb this generates the following: 

   

   @Override
   public String toString() {
     StringBuilder sb_ = new StringBuilder();
     sb_.append(ab);
     sb_.append(sb);
     return sb_.toString();
   }

The underscore is appended to sb to avoid conflicting with the user-supplied sb property. Underscores are also prefixed for names that start with a digit, and used to replace parameterName-unsafe characters like space or dash.

When dealing with multiple independent inner scopes, use a clone() of the NameAllocator used for the outer scope to further refine parameterName allocation for a specific inner scope.

  • Constructor Details

    • NameAllocator

      public NameAllocator()

  • Method Details

    • toJavaIdentifier

      public static String toJavaIdentifier(String suggestion)

    • newName

      public String newName(String suggestion)
      Return a new parameterName using suggestion that will not be a Java identifier or clash with other names.

    • newName

      public String newName(String suggestion, Object tag)
      Return a new parameterName using suggestion that will not be a Java identifier or clash with other names. The returned value can be queried multiple times by passing tag to get(Object).

    • get

      public String get(Object tag)
      Retrieve a parameterName created with newName(String, Object).

    • clone

      public NameAllocator clone()
      Create a deep copy of this NameAllocator. Useful to create multiple independent refinements of a NameAllocator to be used in the respective definition of multiples, independently-scoped, inner code blocks.
      Overrides:
      clone in class Object
      Returns:
      A deep copy of this NameAllocator.