java/src/main/com/google/appengine/api/search/query/QueryTreeVisitor.java

   1 // Copyright 2011 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.search.query;
   4
   5 import org.antlr.runtime.tree.Tree;
   6
   7 /**
   8  * Defines an interface of the visitor invoked by the walker.
   9  *
  10  * @param <T> the type of the context object accompanying visited tree nodes.
  11  *
  12  */
  13 public interface QueryTreeVisitor<T extends QueryTreeContext<T>> {
  14
  15   /**
  16    * Visits a node that represents a sequence of expressions.
  17    */
  18   void visitSequence(Tree node, T context);
  19
  20   /**
  21    * Visits a node that represents a conjunction (logical and) of conditions.
  22    */
  23   void visitConjunction(Tree node, T context);
  24
  25   /**
  26    * Visits a node that represents a disjunction (logical or) of conditions.
  27    */
  28   void visitDisjunction(Tree node, T context);
  29
  30   /**
  31    * Visits a node that represents a negation of conditions.
  32    */
  33   void visitNegation(Tree node, T context);
  34
  35   /**
  36    * Visits a node that represents a text field that is subject to query rewrite.
  37    */
  38   void visitFuzzy(Tree node, T context);
  39
  40   /**
  41    * Visits a node that represents a text field that must not be altered.
  42    */
  43   void visitLiteral(Tree node, T context);
  44
  45   /**
  46    * Visits a node that represents that a field value must be less than some
  47    * specified value.
  48    */
  49   void visitLessThan(Tree node, T context);
  50
  51   /**
  52    * Visits a node that represents that a field value must be less than or
  53    * equal to some specified value.
  54    */
  55   void visitLessOrEqual(Tree node, T context);
  56
  57   /**
  58    * Visits a node that represents that a field value must be greater than some
  59    * specified value.
  60    */
  61   void visitGreaterThan(Tree node, T context);
  62
  63   /**
  64    * Visits a node that represents an inequality between a field and value.
  65    */
  66   void visitGreaterOrEqual(Tree node, T context);
  67
  68   /**
  69    * Visits a node that represents that a field value must be greater than
  70    * or equal to some specified value.
  71    */
  72   void visitEqual(Tree node, T context);
  73
  74   /**
  75    * Visits a node that represents that a field must contain a value.
  76    */
  77   void visitContains(Tree node, T context);
  78
  79   /**
  80    * Visits a node that represents a constant value.
  81    */
  82   void visitValue(Tree node, T context);
  83
  84   /**
  85    * Visits a node that represents a function computed on some arguments.
  86    */
  87   void visitFunction(Tree node, T context);
  88
  89   /**
  90    * Visits a node that represents a global field.
  91    */
  92   void visitGlobal(Tree node, T context);
  93
  94   /**
  95    * Catch-all method for future type of query nodes.
  96    */
  97   void visitOther(Tree node, T context);
  98 }