org.cumulus4j.store.query.eval
Class OrExpressionEvaluator

java.lang.Object
  org.cumulus4j.store.query.eval.AbstractExpressionEvaluator<DyadicExpression>
      org.cumulus4j.store.query.eval.OrExpressionEvaluator

public class OrExpressionEvaluator
extends AbstractExpressionEvaluator<DyadicExpression>

Evaluator handling the boolean operation "||" (OR).

This evaluator works just like the AndExpressionEvaluator with the only difference that it unites the partial results instead of intersecting them.

If the ResultDescriptor indicates a negation, this evaluator delegates to the AndExpressionEvaluator, because a query like "!( a > 5 || b <= 12 )" is internally converted to "a <= 5 && b > 12" for performance reasons. See NotExpressionEvaluator as well as De Morgan's laws in wikipedia for details.

Author:

Marco หงุ่ยตระกูล-Schulze - marco at nightlabs dot de

See Also:

AndExpressionEvaluator

Constructor Summary

OrExpressionEvaluator(AndExpressionEvaluator negatedExpressionEvaluator)

OrExpressionEvaluator(QueryEvaluator queryEvaluator, AbstractExpressionEvaluator<?> parent, DyadicExpression expression)

Method Summary

protected Set<Long>	_queryResultDataEntryIDs(ResultDescriptor resultDescriptor) Execute a query for the given resultDescriptor.
protected Set<Long>	_queryResultDataEntryIDsIgnoringNegation(ResultDescriptor resultDescriptor)
AbstractExpressionEvaluator<? extends Expression>	getLeft() Get the left branch in the tree structure.
AbstractExpressionEvaluator<? extends Expression>	getRight() Get the right branch in the tree structure.

Methods inherited from class org.cumulus4j.store.query.eval.AbstractExpressionEvaluator

_getResultSymbols, _queryResultObjects, getExpression, getFieldType, getParent, getQueryEvaluator, getResultSymbols, queryResultDataEntryIDs, queryResultObjects, setLeft, setRight

Methods inherited from class java.lang.Object

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

Constructor Detail

OrExpressionEvaluator

public OrExpressionEvaluator(QueryEvaluator queryEvaluator,
                             AbstractExpressionEvaluator<?> parent,
                             DyadicExpression expression)

OrExpressionEvaluator

public OrExpressionEvaluator(AndExpressionEvaluator negatedExpressionEvaluator)

Method Detail

getLeft

public AbstractExpressionEvaluator<? extends Expression> getLeft()

Description copied from class: AbstractExpressionEvaluator

Get the left branch in the tree structure.

Overrides:

getLeft in class AbstractExpressionEvaluator<DyadicExpression>

Returns:

the left branch in the tree structure or null if there is none.

See Also:

AbstractExpressionEvaluator.setLeft(AbstractExpressionEvaluator), AbstractExpressionEvaluator.getRight()

getRight

public AbstractExpressionEvaluator<? extends Expression> getRight()

Description copied from class: AbstractExpressionEvaluator

Get the right branch in the tree structure.

Overrides:

getRight in class AbstractExpressionEvaluator<DyadicExpression>

Returns:

the right branch in the tree structure or null if there is none.

See Also:

AbstractExpressionEvaluator.setRight(AbstractExpressionEvaluator), AbstractExpressionEvaluator.getLeft()

_queryResultDataEntryIDs

protected Set<Long> _queryResultDataEntryIDs(ResultDescriptor resultDescriptor)

Description copied from class: AbstractExpressionEvaluator

Execute a query for the given resultDescriptor. This method should contain the concrete logic for AbstractExpressionEvaluator.queryResultDataEntryIDs(ResultDescriptor) and must be implemented by subclasses.

Specified by:

_queryResultDataEntryIDs in class AbstractExpressionEvaluator<DyadicExpression>

Parameters:

resultDescriptor - the descriptor specifying what candidates (usually "this" or a variable) the caller is interested in as well as modifiers (e.g. negation) affecting the query.

Returns:

those dataEntryIDs that match the query criteria for the specified resultSymbol or null, if the symbol is not supported (this should be consistent with the implementation of AbstractExpressionEvaluator._getResultSymbols()).

See Also:

AbstractExpressionEvaluator.queryResultDataEntryIDs(ResultDescriptor)

_queryResultDataEntryIDsIgnoringNegation

protected Set<Long> _queryResultDataEntryIDsIgnoringNegation(ResultDescriptor resultDescriptor)