com.metamatrix.query.sql.lang
Class MatchCriteria

java.lang.Object
  com.metamatrix.query.sql.lang.Criteria
      com.metamatrix.query.sql.lang.PredicateCriteria
          com.metamatrix.query.sql.lang.MatchCriteria

All Implemented Interfaces:

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

public class MatchCriteria
extends PredicateCriteria

This class represents a criteria involving a string expression to be matched against a string expression match value. The match value may contain a few special characters: % represents 0 or more characters and _ represents a single match character. The escape character can be used to escape an actual % or _ within a match string.

See Also:

Serialized Form

Nested Class Summary

static class

MatchCriteria.PatternTranslator Utility to convert the pattern into a different match syntax

Field Summary

static char	MATCH_CHAR The default single match character - '_'
static char	NULL_ESCAPE_CHAR The internal null escape character
static char	WILDCARD_CHAR The default wildcard character - '%'

Constructor Summary

MatchCriteria()
Constructs a default instance of this class.

MatchCriteria(Expression leftExpression, Expression rightExpression)
Constructs an instance of this class from a left and right expression

MatchCriteria(Expression leftExpression, Expression rightExpression, char escapeChar)
Constructs an instance of this class from a left and right expression and an escape character

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.
char	getEscapeChar() Get the escape character, which can be placed before the wildcard or single match character in the expression to prevent it from being used as a wildcard or single match.
Expression	getLeftExpression() Get left expression.
Expression	getRightExpression() Get right expression.
int	hashCode() Get hash code.
boolean	isNegated() Returns whether this criteria is negated.
void	setEscapeChar(char escapeChar) Set the escape character which can be used when the wildcard or single character should be used literally.
void	setLeftExpression(Expression expression) Set left expression.
void	setNegated(boolean negationFlag) Sets the negation flag for this criteria.
void	setRightExpression(Expression expression) Set right expression.

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

WILDCARD_CHAR

public static final char WILDCARD_CHAR

The default wildcard character - '%'

See Also:

Constant Field Values

MATCH_CHAR

public static final char MATCH_CHAR

The default single match character - '_'

See Also:

Constant Field Values

NULL_ESCAPE_CHAR

public static final char NULL_ESCAPE_CHAR

The internal null escape character

See Also:

Constant Field Values

Constructor Detail

MatchCriteria

public MatchCriteria()

Constructs a default instance of this class.

MatchCriteria

public MatchCriteria(Expression leftExpression,
                     Expression rightExpression)

Constructs an instance of this class from a left and right expression

Parameters:

leftExpression - The expression to check

rightExpression - The match expression

MatchCriteria

public MatchCriteria(Expression leftExpression,
                     Expression rightExpression,
                     char escapeChar)

Constructs an instance of this class from a left and right expression and an escape character

Parameters:

leftExpression - The expression to check

rightExpression - The match expression

escapeChar - The escape character, to allow literal use of wildcard and single match chars

Method Detail

setLeftExpression

public void setLeftExpression(Expression expression)

Set left expression.

Parameters:

expression - expression

getLeftExpression

public Expression getLeftExpression()

Get left expression.

Returns:

Left expression

setRightExpression

public void setRightExpression(Expression expression)

Set right expression.

Parameters:

expression - expression

getRightExpression

public Expression getRightExpression()

Get right expression.

Returns:

right expression

getEscapeChar

public char getEscapeChar()

Get the escape character, which can be placed before the wildcard or single match character in the expression to prevent it from being used as a wildcard or single match. The escape character must not be used elsewhere in the expression. For example, to match "35%" without activating % as a wildcard, set the escape character to '$' and use the expression "35$%".

Returns:

Escape character, if not set will return NULL_ESCAPE_CHAR

setEscapeChar

public void setEscapeChar(char escapeChar)

Set the escape character which can be used when the wildcard or single character should be used literally.

Parameters:

escapeChar - New escape character

isNegated

public boolean isNegated()

Returns whether this criteria is negated.

Returns:

flag indicating whether this criteria contains a NOT

setNegated

public void setNegated(boolean negationFlag)

Sets the negation flag for this criteria.

Parameters:

negationFlag - true if this criteria contains a NOT; false otherwise

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.

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 equal

clone

public java.lang.Object clone()

Deep copy of object

Specified by:

clone in interface LanguageObject

Specified by:

clone in class PredicateCriteria

Returns:

Deep copy of object