Package com.squareup.javapoet

Class NameAllocator

  • All Implemented Interfaces:
    java.lang.Cloneable
    public final class NameAllocator
extends java.lang.Object
implements java.lang.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.name(), property);
   }
   nameAllocator.newName("sb", "string builder");
    Pass a unique tag object to each allocation. The tag scopes the name, and can be used to look up the allocated name 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 name-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 name allocation for a specific inner scope.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private java.util.Set<java.lang.String> allocatedNames  
      private java.util.Map<java.lang.Object,​java.lang.String> tagToName  

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
        NameAllocator()  
      private NameAllocator​(java.util.LinkedHashSet<java.lang.String> allocatedNames, java.util.LinkedHashMap<java.lang.Object,​java.lang.String> tagToName)  

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      NameAllocator clone()
      Create a deep copy of this NameAllocator.
      java.lang.String get​(java.lang.Object tag)
      Retrieve a name created with newName(String, Object).
      java.lang.String newName​(java.lang.String suggestion)
      Return a new name using suggestion that will not be a Java identifier or clash with other names.
      java.lang.String newName​(java.lang.String suggestion, java.lang.Object tag)
      Return a new name using suggestion that will not be a Java identifier or clash with other names.
      static java.lang.String toJavaIdentifier​(java.lang.String suggestion)  

      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • allocatedNames

        private final java.util.Set<java.lang.String> allocatedNames

      • tagToName

        private final java.util.Map<java.lang.Object,​java.lang.String> tagToName

    • Constructor Detail

      • NameAllocator

        public NameAllocator()

      • NameAllocator

        private NameAllocator​(java.util.LinkedHashSet<java.lang.String> allocatedNames,
                      java.util.LinkedHashMap<java.lang.Object,​java.lang.String> tagToName)

    • Method Detail

      • newName

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

      • newName

        public java.lang.String newName​(java.lang.String suggestion,
                                java.lang.Object tag)
        Return a new name 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).

      • toJavaIdentifier

        public static java.lang.String toJavaIdentifier​(java.lang.String suggestion)

      • get

        public java.lang.String get​(java.lang.Object tag)
        Retrieve a name 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 java.lang.Object
        Returns:
        A deep copy of this NameAllocator.