com.metamatrix.query.sql.lang
Class SubqueryCompareCriteria

java.lang.Object
  com.metamatrix.query.sql.lang.Criteria
      com.metamatrix.query.sql.lang.PredicateCriteria
          com.metamatrix.query.sql.lang.AbstractCompareCriteria
              com.metamatrix.query.sql.lang.SubqueryCompareCriteria

All Implemented Interfaces:

SubqueryContainer, LanguageObject, ValueIteratorProvider, java.io.Serializable, java.lang.Cloneable

public class SubqueryCompareCriteria
extends AbstractCompareCriteria
implements SubqueryContainer, ValueIteratorProvider

This class implements a quantified comparison predicate. This is a criteria which represents a simple operator relationship between an expression and either a scalar subquery or a table subquery preceded by one of the possible quantifiers.

The quantifiers are:

• NO_QUANTIFIER, meaning the subquery has no quantifier and therefore must be a scalar subquery
• SOME and ANY, which are synonymous - the criteria is true if there is at least one comparison between the left expression and the values of the subquery. The criteria is false if the subquery returns no rows.
• ALL
- the criteria is true only if all of the comparisons between the left expression and each value of the subquery is true. The criteria is also true if the subquery returns no rows.

Some examples are:

• ticker = ANY (Select ... FROM ... WHERE ... )
• price >= ALL (Select ... FROM ... WHERE ... )
• revenue < (Select ... FROM ... WHERE ... )

See Also:

Serialized Form

Field Summary

static int	ALL "All" predicate quantifier
static int	ANY "Any" predicate quantifier (equivalent to "Some")
static int	NO_QUANTIFIER "All" predicate quantifier
static int	SOME "Some" predicate quantifier (equivalent to "Any")

Fields inherited from class com.metamatrix.query.sql.lang.AbstractCompareCriteria

EQ, GE, GT, LE, LT, NE

Constructor Summary

SubqueryCompareCriteria()

SubqueryCompareCriteria(Expression leftExpression, Command subCommand, int operator, int predicateQuantifier)

Method Summary

void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
java.lang.Object	clone() Deep copy of object.
boolean	equals(java.lang.Object obj) Override equals() method.
Command	getCommand() Returns the subquery Command object
int	getPredicateQuantifier() Get the predicate quantifier - returns one of the following: NO_QUANTIFIER ANY SOME ALL
java.lang.String	getPredicateQuantifierAsString() Returns the predicate quantifier as a string.
Expression	getRightExpression()
ValueIterator	getValueIterator() Returns always the same instance of a ValueIterator, but resets it each time this method is called
int	hashCode() Get hash code.
void	setCommand(Command command) Set the subquery command (either a SELECT or a procedure execution).
void	setPredicateQuantifier(int predicateQuantifier) Set the predicate quantifier - use one of the following: NO_QUANTIFIER ANY SOME ALL
void	setValueIterator(ValueIterator valueIterator) Set the ValueIterator on this object (the ValueIterator will encapsulate the single-column results of the subquery processor plan).

Methods inherited from class com.metamatrix.query.sql.lang.AbstractCompareCriteria

getLeftExpression, getOperator, getOperator, getOperatorAsString, setLeftExpression, setOperator

Methods inherited from class com.metamatrix.query.sql.lang.Criteria

combineCriteria, combineCriteria, combineCriteria, separateCriteriaByAnd, toConjunctiveNormalForm, toDisjunctiveNormalForm, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

NO_QUANTIFIER

public static final int NO_QUANTIFIER

"All" predicate quantifier

See Also:

Constant Field Values

SOME

public static final int SOME

"Some" predicate quantifier (equivalent to "Any")

See Also:

Constant Field Values

ANY

public static final int ANY

"Any" predicate quantifier (equivalent to "Some")

See Also:

Constant Field Values

ALL

public static final int ALL

"All" predicate quantifier

See Also:

Constant Field Values

Constructor Detail

SubqueryCompareCriteria

public SubqueryCompareCriteria()

SubqueryCompareCriteria

public SubqueryCompareCriteria(Expression leftExpression,
                               Command subCommand,
                               int operator,
                               int predicateQuantifier)

Method Detail

getPredicateQuantifier

public int getPredicateQuantifier()

Get the predicate quantifier - returns one of the following:

• NO_QUANTIFIER
• ANY
• SOME
• ALL

Returns:

the predicate quantifier

setPredicateQuantifier

public void setPredicateQuantifier(int predicateQuantifier)

Set the predicate quantifier - use one of the following:

• NO_QUANTIFIER
• ANY
• SOME
• ALL

Parameters:

predicateQuantifier - the predicate quantifier

getCommand

public Command getCommand()

Description copied from interface: SubqueryContainer

Returns the subquery Command object

Specified by:

getCommand in interface SubqueryContainer

Returns:

the subquery Command object

See Also:

com.metamatrix.query.sql.lang.SubqueryCriteria#getCommand()

setCommand

public void setCommand(Command command)

Set the subquery command (either a SELECT or a procedure execution).

Specified by:

setCommand in interface SubqueryContainer

Parameters:

command - Command to execute to get the values for the criteria

getValueIterator

public ValueIterator getValueIterator()

Returns always the same instance of a ValueIterator, but resets it each time this method is called

Specified by:

getValueIterator in interface ValueIteratorProvider

Returns:

this object's ValueIterator instance (always the same instance)

Throws:

MetaMatrixRuntimeException - if the subquery for this set criteria has not yet been processed and no value iterator is available

See Also:

com.metamatrix.query.sql.lang.SubqueryCriteria#getValueIterator()

setValueIterator

public void setValueIterator(ValueIterator valueIterator)

Set the ValueIterator on this object (the ValueIterator will encapsulate the single-column results of the subquery processor plan). This ValueIterator must be set before processing (before the Criteria can be evaluated). Also, this ValueIterator should be considered transient - only available during processing - and it will not be cloned should this Criteria object be cloned.

Specified by:

setValueIterator in interface ValueIteratorProvider

Parameters:

valueIterator - encapsulating the results of the sub query

getPredicateQuantifierAsString

public java.lang.String getPredicateQuantifierAsString()

Returns the predicate quantifier as a string.

Returns:

String version of predicate quantifier

acceptVisitor

public void acceptVisitor(LanguageVisitor visitor)

Description copied from interface: LanguageObject

Method for accepting a visitor. It is the responsibility of the language object to call back on the visitor.

Specified by:

acceptVisitor in interface LanguageObject

Parameters:

visitor - Visitor being used

hashCode

public int hashCode()

Get hash code. WARNING: The hash code is based on data in the criteria. If data values are changed, the hash code will change - don't hash this object and change values.

Overrides:

hashCode in class java.lang.Object

Returns:

Hash code

equals

public boolean equals(java.lang.Object obj)

Override equals() method.

Overrides:

equals in class java.lang.Object

Parameters:

obj - Other object

Returns:

true if objects are equivalent

clone

public java.lang.Object clone()

Deep copy of object. The values Iterator of this object will not be cloned - it will be null in the new object (see #setValueIterator setValueIterator}).

Specified by:

clone in interface LanguageObject

Specified by:

clone in class PredicateCriteria

Returns:

Deep copy of object

See Also:

Object.clone()

getRightExpression

public Expression getRightExpression()

Specified by:

getRightExpression in class AbstractCompareCriteria

See Also:

AbstractCompareCriteria.getRightExpression()