/**
* Remove the specified function from the provided DataBase connection
*
* @param st Active statement
* @param function function to remove
* @throws SQLException
*/
public static void unRegisterFunction(Statement st, Function function) throws SQLException {
String functionAlias = getStringProperty(function, Function.PROP_NAME);
if (functionAlias.isEmpty()) {
functionAlias = function.getClass().getSimpleName();
}
st.execute("DROP ALIAS IF EXISTS " + functionAlias);
}
/**
* @param function Function instance
* @return the function ALIAS, name of the function in SQL engine
*/
public static String getAlias(Function function) {
String functionAlias = getStringProperty(function, Function.PROP_NAME);
if (!functionAlias.isEmpty()) {
return functionAlias;
}
return function.getClass().getSimpleName();
}
/**
* Create java code to add function copy paste into GeoSpatialFunctionsAddRemove to upload it
*
* @param st SQL Statement
* @param function Function instance
* @param packagePrepend For OSGi environment only, use Bundle-SymbolicName:Bundle-Version:
* @param dropAlias Drop alias if exists before define it.
*/
public static void registerFunction(
Statement st, Function function, String packagePrepend, boolean dropAlias)
throws SQLException {
String functionClass = function.getClass().getName();
String functionAlias = getAlias(function);
if (function instanceof ScalarFunction) {
ScalarFunction scalarFunction = (ScalarFunction) function;
String functionName = scalarFunction.getJavaStaticMethod();
if (dropAlias) {
st.execute("DROP ALIAS IF EXISTS " + functionAlias);
}
String deterministic = "";
if (getBooleanProperty(function, ScalarFunction.PROP_DETERMINISTIC, false)) {
deterministic = " DETERMINISTIC";
}
String nobuffer = "";
if (getBooleanProperty(function, ScalarFunction.PROP_NOBUFFER, false)) {
nobuffer = " NOBUFFER";
}
// Create alias, H2 does not support prepare statement on create alias
st.execute(
"CREATE ALIAS IF NOT EXISTS "
+ functionAlias
+ deterministic
+ nobuffer
+ " FOR \""
+ packagePrepend
+ functionClass
+ "."
+ functionName
+ "\"");
// Set comment
String functionRemarks = getStringProperty(function, Function.PROP_REMARKS);
if (!functionRemarks.isEmpty()) {
PreparedStatement ps =
st.getConnection().prepareStatement("COMMENT ON ALIAS " + functionAlias + " IS ?");
ps.setString(1, functionRemarks);
ps.execute();
}
} else if (function instanceof Aggregate) {
st.execute(
"CREATE AGGREGATE IF NOT EXISTS "
+ functionAlias
+ " FOR \""
+ packagePrepend
+ functionClass
+ "\"");
} else {
throw new SQLException("Unsupported function " + functionClass);
}
}
private static boolean getBooleanProperty(
Function function, String propertyKey, boolean defaultValue) {
Object value = function.getProperty(propertyKey);
return value instanceof Boolean ? (Boolean) value : defaultValue;
}
private static String getStringProperty(Function function, String propertyKey) {
Object value = function.getProperty(propertyKey);
return value instanceof String ? (String) value : "";
}
