de.ipcon.db.oql.predicate

Interface OQLExpressionEvaluatorI<T extends ParseTreeNode>

All Known Implementing Classes:

BinaryExpressionEvaluator, ExpressionEvalBase, FunctionEvaluator, ListEvaluator, LiteralEvaluator, ParameterEvaluator, PathNodeEvaluator, UnaryEvaluator, WherePredicate

public interface OQLExpressionEvaluatorI<T extends ParseTreeNode>

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.Object	INNER_JOIN_FILTERED_OUT The "STATE" of an expression being filtered out due to an inner join occurring somewhere.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getAlias()
java.util.List<? extends OQLExpressionEvaluatorI<?>>	getChildren() Nonnull list of available children
EntityI	getEntity() The entity of the current context
T	getNode() The parsed OQL Node that belongs to this expression evaluator
java.lang.Object[]	getParameters() Fixed parameter provided to the OQL Query
OQLExpressionEvaluatorI<?>	getParent() The parent evaluator
SchemaI	getSchema() The schema to use for evaluation.
java.lang.Object	getValue(BOI bo) Computes the raw value of the expression evaluated on the provided BO.

Field Detail

INNER_JOIN_FILTERED_OUT

static final java.lang.Object INNER_JOIN_FILTERED_OUT

The "STATE" of an expression being filtered out due to an inner join occurring somewhere. In most cases, this result is used as a shortcut to evaluate the final predicate into false. However, for existing cross product joins only a specific join is filtered out, not everything. This is needed, because "null" for SQLs localized "UNKNOWN" state.

Method Detail

getValue

java.lang.Object getValue(BOI bo)

Computes the raw value of the expression evaluated on the provided BO. Can return a flat Collection (Sets preferred) if the evaluation contains a join and has multiple results due to the internally created cross-product.

Parameters:

bo - the nonnull root BO to evaluate the node on

Returns:

the raw value of the OQL expression that this predicate represents. Can be an arbitrary return value, e.g. Strings, Boolean, INNER_JOIN_FILTERED_OUT, null, etc.

getParent

OQLExpressionEvaluatorI<?> getParent()

The parent evaluator

getChildren

java.util.List<? extends OQLExpressionEvaluatorI<?>> getChildren()

Nonnull list of available children

getNode

T getNode()

The parsed OQL Node that belongs to this expression evaluator

getSchema

SchemaI getSchema()

The schema to use for evaluation. In Unittests, the provided BOI might not have a schema assigned

getEntity

EntityI getEntity()

The entity of the current context

getParameters

java.lang.Object[] getParameters()

Fixed parameter provided to the OQL Query

getAlias

java.lang.String getAlias()

Returns:

the current Alias in the OQL Query