org.netbeans.spi.lexer

Interface TokenPropertyProvider<T extends TokenId>

public interface TokenPropertyProvider<T extends TokenId>

Provides extra properties of a token.
Normally each token has an extra instance of the property provider:

 final class MyTokenPropertyProvider implements TokenPropertyProvider {

     private final Object value;

     TokenPropProvider(Object value) {
         this.value = value;
     }
      
     public Object getValue (Token token, Object key) {
         if ("type".equals(key))
             return value;
         return null;
     }

 }
 

However multiple flyweight instances of the provider may be used to save memory if there are just several values for a property.
Example of two instances of a provider for boolean property "key":

 final class MyTokenPropertyProvider implements TokenPropertyProvider {

     static final MyTokenPropertyProvider TRUE = new MyTokenPropertyProvider(Boolean.TRUE);

     static final MyTokenPropertyProvider FALSE = new MyTokenPropertyProvider(Boolean.FALSE);
 
     private final Boolean value;

     private MyTokenPropertyProvider(Boolean value) {
         this.value = value;
     }

     public Object getValue(Token<T> token, Object key) {
         if ("key".equals(key)) {
             return value;
         }
         return null;
     }

 }
 

A special kind of token PropertyToken allows to carry token properties.

Method Summary

Modifier and Type	Method and Description
Object	getValue(Token<T> token, Object key) Get value of a token property.

Method Detail

getValue

Object getValue(Token<T> token,
                Object key)

Get value of a token property.

Parameters:

token - non-null token for which the property is being retrieved. It might be useful if the property would be computed dynamically.

key - non-null key for which the value should be retrieved.

Returns:

value of the property or null if there is no value for the given key.