AnsiTrimEmulationFunctionpublic class AnsiTrimEmulationFunction extends Object implements SQLFunction| A {@link SQLFunction} implementation that emulates the ANSI SQL trim function
on dialects which do not support the full definition. However, this function
definition does assume the availability of ltrim, rtrim, and replace functions
which it uses in various combinations to emulate the desired ANSI trim()
functionality. |
| Fields Summary |
|---|
| private static final SQLFunction | LEADING_SPACE_TRIM | | private static final SQLFunction | TRAILING_SPACE_TRIM | | private static final SQLFunction | BOTH_SPACE_TRIM | | private static final SQLFunction | BOTH_SPACE_TRIM_FROM | | private static final SQLFunction | LEADING_TRIM | | private static final SQLFunction | TRAILING_TRIM | | private static final SQLFunction | BOTH_TRIM |
| Methods Summary |
|---|
| public org.hibernate.type.Type | getReturnType(org.hibernate.type.Type columnType, org.hibernate.engine.Mapping mapping)
return Hibernate.STRING;
| | public boolean | hasArguments()
return true;
| | public boolean | hasParenthesesIfNoArguments()
return false;
| | public java.lang.String | render(java.util.List args, org.hibernate.engine.SessionFactoryImplementor factory)
// according to both the ANSI-SQL and EJB3 specs, trim can either take
// exactly one parameter or a variable number of parameters between 1 and 4.
// from the SQL spec:
//
// <trim function> ::=
// TRIM <left paren> <trim operands> <right paren>
//
// <trim operands> ::=
// [ [ <trim specification> ] [ <trim character> ] FROM ] <trim source>
//
// <trim specification> ::=
// LEADING
// | TRAILING
// | BOTH
//
// If only <trim specification> is omitted, BOTH is assumed;
// if <trim character> is omitted, space is assumed
if ( args.size() == 1 ) {
// we have the form: trim(trimSource)
// so we trim leading and trailing spaces
return BOTH_SPACE_TRIM.render( args, factory );
}
else if ( "from".equalsIgnoreCase( ( String ) args.get( 0 ) ) ) {
// we have the form: trim(from trimSource).
// This is functionally equivalent to trim(trimSource)
return BOTH_SPACE_TRIM_FROM.render( args, factory );
}
else {
// otherwise, a trim-specification and/or a trim-character
// have been specified; we need to decide which options
// are present and "do the right thing"
boolean leading = true; // should leading trim-characters be trimmed?
boolean trailing = true; // should trailing trim-characters be trimmed?
String trimCharacter = null; // the trim-character
String trimSource = null; // the trim-source
// potentialTrimCharacterArgIndex = 1 assumes that a
// trim-specification has been specified. we handle the
// exception to that explicitly
int potentialTrimCharacterArgIndex = 1;
String firstArg = ( String ) args.get( 0 );
if ( "leading".equalsIgnoreCase( firstArg ) ) {
trailing = false;
}
else if ( "trailing".equalsIgnoreCase( firstArg ) ) {
leading = false;
}
else if ( "both".equalsIgnoreCase( firstArg ) ) {
}
else {
potentialTrimCharacterArgIndex = 0;
}
String potentialTrimCharacter = ( String ) args.get( potentialTrimCharacterArgIndex );
if ( "from".equalsIgnoreCase( potentialTrimCharacter ) ) {
trimCharacter = "' '";
trimSource = ( String ) args.get( potentialTrimCharacterArgIndex + 1 );
}
else if ( potentialTrimCharacterArgIndex + 1 >= args.size() ) {
trimCharacter = "' '";
trimSource = potentialTrimCharacter;
}
else {
trimCharacter = potentialTrimCharacter;
if ( "from".equalsIgnoreCase( ( String ) args.get( potentialTrimCharacterArgIndex + 1 ) ) ) {
trimSource = ( String ) args.get( potentialTrimCharacterArgIndex + 2 );
}
else {
trimSource = ( String ) args.get( potentialTrimCharacterArgIndex + 1 );
}
}
List argsToUse = null;
argsToUse = new ArrayList();
argsToUse.add( trimSource );
argsToUse.add( trimCharacter );
if ( trimCharacter.equals( "' '" ) ) {
if ( leading && trailing ) {
return BOTH_SPACE_TRIM.render( argsToUse, factory );
}
else if ( leading ) {
return LEADING_SPACE_TRIM.render( argsToUse, factory );
}
else {
return TRAILING_SPACE_TRIM.render( argsToUse, factory );
}
}
else {
if ( leading && trailing ) {
return BOTH_TRIM.render( argsToUse, factory );
}
else if ( leading ) {
return LEADING_TRIM.render( argsToUse, factory );
}
else {
return TRAILING_TRIM.render( argsToUse, factory );
}
}
}
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