org.cloudgraph.hbase.filter

Class RowPredicateVisitor

java.lang.Object

org.plasma.query.visitor.DefaultQueryVisitor

org.cloudgraph.query.expr.ExpresionVisitorSupport

org.cloudgraph.hbase.filter.FilterHierarchyAssembler

org.cloudgraph.hbase.filter.PredicateVisitor

org.cloudgraph.hbase.filter.RowPredicateVisitor

All Implemented Interfaces:

Assembler, HBaseFilterAssembler, org.plasma.query.visitor.QueryVisitor

Direct Known Subclasses:

PredicateRowFilterAssembler

public class RowPredicateVisitor
extends PredicateVisitor

Creates a hierarchy of regular expression based HBase row filters using GraphRowKeyExpressionFactory and HBase RegexStringComparator. Processes visitor events for query model elements specific to assembly of HBase row filters, such as properties, wildcards, literals, logical operators, relational operators, within the context of HBase filter hierarchy assembly. Maintains various context information useful to subclasses.

HBase filters may be collected into lists using FilterList each with a MUST_PASS_ALL or MUST_PASS_ONE (logical) operator. Lists may then be assembled into hierarchies used to represent complex expression trees filtering either rows or columns in HBase.

Since:

0.5

Author:

Scott Cinnamond

See Also:

GraphRowKeyExpressionFactory

Field Summary

Fields

Modifier and Type	Field and Description
protected String	contextPropertyPath
protected GraphRowKeyExpressionFactory	rowKeyFac

Fields inherited from class org.cloudgraph.hbase.filter.PredicateVisitor

contextHBaseCompareOp, contextOpWildcard, contextProperty, contextType, contextWildcardOperator

Fields inherited from class org.cloudgraph.hbase.filter.FilterHierarchyAssembler

filterStack, params, rootFilter, rootType

Constructor Summary

Constructors

Constructor and Description
RowPredicateVisitor(org.plasma.sdo.PlasmaType rootType)

Method Summary

Modifier and Type	Method and Description
void	end(org.plasma.query.model.Expression expression) Process the traversal end event for a query expression removing the current (top) HBase filter list from the stack.
void	start(org.plasma.query.model.Expression expression) Process the traversal start event for a query expression creating a new HBase filter list with a default MUST_PASS_ALL operator and pushes it onto the stack.
void	start(org.plasma.query.model.Literal literal) Process the traversal start event for a query literal within an expression creating an HBase row filter and adding it to the filter hierarchy.
void	start(org.plasma.query.model.LogicalOperator operator) Process a logical operator query traversal start event.
void	start(org.plasma.query.model.NullLiteral nullLiteral) (non-Javadoc)
void	start(org.plasma.query.model.PredicateOperator operator)
void	start(org.plasma.query.model.Property property) Process the traversal start event for a query property within an expression just traversing the property path if exists and capturing context information for the current expression.

Methods inherited from class org.cloudgraph.hbase.filter.PredicateVisitor

clear, start, start

Methods inherited from class org.cloudgraph.hbase.filter.FilterHierarchyAssembler

filterTokens, getFilter, getParams, log, popFilter, pushFilter, pushFilter

Methods inherited from class org.cloudgraph.query.expr.ExpresionVisitorSupport

getChildExpressionCount, getChildExpressions, getLogicalOperatorCount, hasChildExpressions, hasWildcard

Methods inherited from class org.plasma.query.visitor.DefaultQueryVisitor

end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, end, getContext, start, start, start, start, start, start, start, start, start, start, start, start, start, start, start, start, start

Methods inherited from class java.lang.Object

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

Field Detail

contextPropertyPath

protected String contextPropertyPath

rowKeyFac

protected GraphRowKeyExpressionFactory rowKeyFac

Constructor Detail

RowPredicateVisitor

public RowPredicateVisitor(org.plasma.sdo.PlasmaType rootType)

Method Detail

start

public void start(org.plasma.query.model.Expression expression)

Process the traversal start event for a query expression creating a new HBase filter list with a default MUST_PASS_ALL operator and pushes it onto the stack. Any subsequent literals encountered then cause a new row filter to be created and added to this new filter list which is on the top of the stack.

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor

Parameters:

expression - the expression

end

public void end(org.plasma.query.model.Expression expression)

Process the traversal end event for a query expression removing the current (top) HBase filter list from the stack.

Specified by:

end in interface org.plasma.query.visitor.QueryVisitor

Overrides:

end in class org.plasma.query.visitor.DefaultQueryVisitor

Parameters:

expression - the expression

start

public void start(org.plasma.query.model.Property property)

Process the traversal start event for a query property within an expression just traversing the property path if exists and capturing context information for the current expression.

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor

See Also:

DefaultQueryVisitor.start(org.plasma.query.model.Property)

start

public void start(org.plasma.query.model.PredicateOperator operator)

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor

start

public void start(org.plasma.query.model.Literal literal)

Process the traversal start event for a query literal within an expression creating an HBase row filter and adding it to the filter hierarchy. Looks at the context under which the literal is encountered and if a user defined row key token configuration is found, creates a regular expression based HBase row filter.

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor

Parameters:

literal - the expression literal

Throws:

GraphFilterException - if no user defined row-key token is configured for the current literal context.

start

public void start(org.plasma.query.model.NullLiteral nullLiteral)

(non-Javadoc)

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor

See Also:

DefaultQueryVisitor.start(org.plasma.query.model.NullLiteral)

start

public void start(org.plasma.query.model.LogicalOperator operator)

Process a logical operator query traversal start event. If the filter list on the top of the filter stack is not an 'OR' filter, since it's immutable and we cannot modify its operator, create an 'OR' filter and swaps out the existing filters into the new 'OR' filter list.

Specified by:

start in interface org.plasma.query.visitor.QueryVisitor

Overrides:

start in class org.plasma.query.visitor.DefaultQueryVisitor