T
- type of the result determined by the Evaluator
used.public class ParseTreeWalker<T> extends Object implements PredicateWalkerBase
PredicateWalkerBase
traverses the parse tree of a CMIS query.
It uses an Evaluator
to accumulate the result of the traversal. Evaluator
has a corresponding method for each node type
in the parse tree.
ParseTreeWalker
calls these methods while traversing the parse tree passing an
Evaluator
for each of the corresponding operation's arguments.
The walkPredicate(Tree)
serves as entry point for traversing a parse tree. After
successful traversal, the result is obtained from the getResult()
method.Constructor and Description |
---|
ParseTreeWalker(Evaluator<T> evaluator)
Create a new instance for traversing CMIS query parse trees.
|
Modifier and Type | Method and Description |
---|---|
T |
getResult()
Retrieve the result of a successful traversal.
|
protected T |
walkOtherExpr(Evaluator<?> evaluator,
org.antlr.runtime.tree.Tree node)
For extensibility.
|
protected T |
walkOtherPredicate(Evaluator<?> evaluator,
org.antlr.runtime.tree.Tree node)
For extensibility.
|
Boolean |
walkPredicate(org.antlr.runtime.tree.Tree node) |
public T getResult()
null
if either not yet traversed, an error occurred
on traversal or the query has an empty where clause.public Boolean walkPredicate(org.antlr.runtime.tree.Tree node)
walkPredicate
in interface PredicateWalkerBase
protected T walkOtherExpr(Evaluator<?> evaluator, org.antlr.runtime.tree.Tree node)
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