Package org.apache.vxquery.compiler.rewriter.rules

Class RemoveRedundantDataExpressionsRule

java.lang.Object

org.apache.vxquery.compiler.rewriter.rules.AbstractRemoveRedundantTypeExpressionsRule

org.apache.vxquery.compiler.rewriter.rules.RemoveRedundantDataExpressionsRule

All Implemented Interfaces:

org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule

public class RemoveRedundantDataExpressionsRule
extends AbstractRemoveRedundantTypeExpressionsRule

The rule searches for where the xquery data function is used. When the expression's return type is atomic, the data function is removed.

 Before
 
   plan__parent
   %OPERATOR( $v1 : data( \@input_expression ) )
   plan__child
   
   Where \@input_expression creates an atomic value.
   
 After 
 
   plan__parent
   %OPERATOR( $v1 : \@input_expression )
   plan__child
 

Author:

prestonc

Constructor Summary

Constructors

Constructor	Description
RemoveRedundantDataExpressionsRule()

Method Summary

Modifier and Type	Method	Description
protected org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier	getSearchFunction()
boolean	hasTypeArgument()
boolean	matchesAllInstancesOf(SequenceType sTypeArg, SequenceType sTypeOutput)

Methods inherited from class org.apache.vxquery.compiler.rewriter.rules.AbstractRemoveRedundantTypeExpressionsRule

rewritePost, rewritePre

Methods inherited from class java.lang.Object

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

Constructor Detail

RemoveRedundantDataExpressionsRule

public RemoveRedundantDataExpressionsRule()

Method Detail

getSearchFunction

protected org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier getSearchFunction()

Specified by:

getSearchFunction in class AbstractRemoveRedundantTypeExpressionsRule

hasTypeArgument

public boolean hasTypeArgument()

Overrides:

hasTypeArgument in class AbstractRemoveRedundantTypeExpressionsRule

matchesAllInstancesOf

public boolean matchesAllInstancesOf(SequenceType sTypeArg,
                                     SequenceType sTypeOutput)

Specified by:

matchesAllInstancesOf in class AbstractRemoveRedundantTypeExpressionsRule