org.cloudgraph.hbase.graph

Class ExternalEdgeRecognizerRelationalBinaryExpr

java.lang.Object

org.cloudgraph.query.expr.DefaultExpr

org.cloudgraph.query.expr.DefaultBinaryExpr

org.cloudgraph.query.expr.DefaultRelationalBinaryExpr

org.cloudgraph.hbase.graph.ExternalEdgeRecognizerRelationalBinaryExpr

All Implemented Interfaces:

BinaryExpr, Expr, RelationalBinaryExpr, org.plasma.query.Term

public class ExternalEdgeRecognizerRelationalBinaryExpr
extends DefaultRelationalBinaryExpr
implements RelationalBinaryExpr

An RelationalBinaryExpr implementation which uses a specific evaluation context to locate or recognize a given sequence based column qualifier within the context of the expression.

For external edges, we have only the row key fields to evaluate and the predicate tree may contain predicates with properties which target fields anywhere in the target graph including properties outside the row key. So for external edge evaluators always return true when a value is not found.

Since:

1.0.4

Author:

Scott Cinnamond

See Also:

ExternalEdgeRecognizerContext

Field Summary

Fields

Modifier and Type	Field and Description
protected Endpoint	endpoint
protected GraphRecognizerSupport	recognizer

Fields inherited from class org.cloudgraph.query.expr.DefaultRelationalBinaryExpr

literal, operator, property, propertyPath

Constructor Summary

Constructors

Constructor and Description
ExternalEdgeRecognizerRelationalBinaryExpr(org.plasma.query.model.Property property, org.plasma.query.model.Literal literal, org.plasma.query.model.RelationalOperator operator) Constructs an expression based on the given terms and column qualifier prefix.

Method Summary

Modifier and Type	Method and Description
boolean	evaluate(EvaluationContext context) Returns a "truth" value for the expression using a specific evaluation context to locate or recognize a given row key field within the context of the expression.

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

getLiteral, getOperator, getProperty, getPropertyPath, toString

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

accept, createPropertyPath, getLeft, getRight, setLeft, setRight

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cloudgraph.query.expr.RelationalBinaryExpr

getLiteral, getOperator, getProperty, getPropertyPath

Methods inherited from interface org.cloudgraph.query.expr.BinaryExpr

accept, getLeft, getRight

Field Detail

endpoint

protected Endpoint endpoint

recognizer

protected GraphRecognizerSupport recognizer

Constructor Detail

ExternalEdgeRecognizerRelationalBinaryExpr

public ExternalEdgeRecognizerRelationalBinaryExpr(org.plasma.query.model.Property property,
                                                  org.plasma.query.model.Literal literal,
                                                  org.plasma.query.model.RelationalOperator operator)

Constructs an expression based on the given terms and column qualifier prefix.

Parameters:

property - the "left" property term

literal - the "right" literal term

operator - the relational operator

See Also:

LocalEdgeRecognizerContext

Method Detail

evaluate

public boolean evaluate(EvaluationContext context)

Returns a "truth" value for the expression using a specific evaluation context to locate or recognize a given row key field within the context of the expression.

For external edges, we have only the row key fields to evaluate and the predicate tree may contain predicates with properties which target fields anywhere in the target graph including properties outside the row key. So for external edge evaluators always return true when a value is not found, but indicate the row evaluation was not complete so downstream actions can be taken.

Specified by:

evaluate in interface Expr

Overrides:

evaluate in class DefaultRelationalBinaryExpr

Parameters:

context -

Returns:

a "truth" value for the expression using a specific evaluation context to locate or recognize a given row key field within the context of the expression.

See Also:

LocalEdgeRecognizerContext