package org.hibernate.dialect.function;
import org.hibernate.Hibernate;
/**
* 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.
*
* @author Steve Ebersole
*/
public class AnsiTrimEmulationFunction extends AbstractAnsiTrimEmulationFunction {
public static final String LTRIM = "ltrim";
public static final String RTRIM = "rtrim";
public static final String REPLACE = "replace";
public static final String SPACE_PLACEHOLDER = "${space}$";
public static final String LEADING_SPACE_TRIM_TEMPLATE = LTRIM + "(?1)";
public static final String TRAILING_SPACE_TRIM_TEMPLATE = RTRIM + "(?1)";
public static final String BOTH_SPACE_TRIM_TEMPLATE = LTRIM + "(" + RTRIM + "(?1))";
public static final String BOTH_SPACE_TRIM_FROM_TEMPLATE = LTRIM + "(" + RTRIM + "(?2))"; //skip the FROM keyword in params
/**
* A template for the series of calls required to trim non-space chars from the beginning of text.
* <p/>
* NOTE : essentially we:</ol>
* <li>replace all space chars with the text '${space}$'</li>
* <li>replace all the actual replacement chars with space chars</li>
* <li>perform left-trimming (that removes any of the space chars we just added which occur at the beginning of the text)</li>
* <li>replace all space chars with the replacement char</li>
* <li>replace all the '${space}$' text with space chars</li>
* </ol>
*/
public static final String LEADING_TRIM_TEMPLATE =
REPLACE + "(" +
REPLACE + "(" +
LTRIM + "(" +
REPLACE + "(" +
REPLACE + "(" +
"?1," +
"' '," +
"'" + SPACE_PLACEHOLDER + "'" +
")," +
"?2," +
"' '" +
")" +
")," +
"' '," +
"?2" +
")," +
"'" + SPACE_PLACEHOLDER + "'," +
"' '" +
")";
/**
* A template for the series of calls required to trim non-space chars from the end of text.
* <p/>
* NOTE: essentially the same series of calls as outlined in {@link #LEADING_TRIM_TEMPLATE} except that here,
* instead of left-trimming the added spaces, we right-trim them to remove them from the end of the text.
*/
public static final String TRAILING_TRIM_TEMPLATE =
REPLACE + "(" +
REPLACE + "(" +
RTRIM + "(" +
REPLACE + "(" +
REPLACE + "(" +
"?1," +
"' '," +
"'" + SPACE_PLACEHOLDER + "'" +
")," +
"?2," +
"' '" +
")" +
")," +
"' '," +
"?2" +
")," +
"'" + SPACE_PLACEHOLDER + "'," +
"' '" +
")";
/**
* A template for the series of calls required to trim non-space chars from both the beginning and the end of text.
* <p/>
* NOTE: again, we have a series of calls that is essentially the same as outlined in {@link #LEADING_TRIM_TEMPLATE}
* except that here we perform both left (leading) and right (trailing) trimming.
*/
public static final String BOTH_TRIM_TEMPLATE =
REPLACE + "(" +
REPLACE + "(" +
LTRIM + "(" +
RTRIM + "(" +
REPLACE + "(" +
REPLACE + "(" +
"?1," +
"' '," +
"'" + SPACE_PLACEHOLDER + "'" +
")," +
"?2," +
"' '" +
")" +
")" +
")," +
"' '," +
"?2" +
")," +
"'" + SPACE_PLACEHOLDER + "'," +
"' '" +
")";
private final SQLFunction leadingSpaceTrim;
private final SQLFunction trailingSpaceTrim;
private final SQLFunction bothSpaceTrim;
private final SQLFunction bothSpaceTrimFrom;
private final SQLFunction leadingTrim;
private final SQLFunction trailingTrim;
private final SQLFunction bothTrim;
/**
* Constructs a new AnsiTrimEmulationFunction using {@link #LTRIM}, {@link #RTRIM}, and {@link #REPLACE}
* respectively.
*
* @see #AnsiTrimEmulationFunction(String,String,String)
*/
public AnsiTrimEmulationFunction() {
this( LTRIM, RTRIM, REPLACE );
}
/**
* Constructs a <tt>trim()</tt> emulation function definition using the specified function calls.
*
* @param ltrimFunctionName The <tt>left trim</tt> function to use.
* @param rtrimFunctionName The <tt>right trim</tt> function to use.
* @param replaceFunctionName The <tt>replace</tt> function to use.
*/
public AnsiTrimEmulationFunction(String ltrimFunctionName, String rtrimFunctionName, String replaceFunctionName) {
leadingSpaceTrim = new SQLFunctionTemplate(
Hibernate.STRING,
LEADING_SPACE_TRIM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
);
trailingSpaceTrim = new SQLFunctionTemplate(
Hibernate.STRING,
TRAILING_SPACE_TRIM_TEMPLATE.replaceAll( RTRIM, rtrimFunctionName )
);
bothSpaceTrim = new SQLFunctionTemplate(
Hibernate.STRING,
BOTH_SPACE_TRIM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
.replaceAll( RTRIM, rtrimFunctionName )
);
bothSpaceTrimFrom = new SQLFunctionTemplate(
Hibernate.STRING,
BOTH_SPACE_TRIM_FROM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
.replaceAll( RTRIM, rtrimFunctionName )
);
leadingTrim = new SQLFunctionTemplate(
Hibernate.STRING,
LEADING_TRIM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
.replaceAll( RTRIM, rtrimFunctionName )
.replaceAll( REPLACE,replaceFunctionName )
);
trailingTrim = new SQLFunctionTemplate(
Hibernate.STRING,
TRAILING_TRIM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
.replaceAll( RTRIM, rtrimFunctionName )
.replaceAll( REPLACE,replaceFunctionName )
);
bothTrim = new SQLFunctionTemplate(
Hibernate.STRING,
BOTH_TRIM_TEMPLATE.replaceAll( LTRIM, ltrimFunctionName )
.replaceAll( RTRIM, rtrimFunctionName )
.replaceAll( REPLACE,replaceFunctionName )
);
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveBothSpaceTrimFunction() {
return bothSpaceTrim;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveBothSpaceTrimFromFunction() {
return bothSpaceTrimFrom;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveLeadingSpaceTrimFunction() {
return leadingSpaceTrim;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveTrailingSpaceTrimFunction() {
return trailingSpaceTrim;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveBothTrimFunction() {
return bothTrim;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveLeadingTrimFunction() {
return leadingTrim;
}
/**
* {@inheritDoc}
*/
protected SQLFunction resolveTrailingTrimFunction() {
return trailingTrim;
}
}
|