in sql2019book/ch5_modern_development_platform/java/RegexSample.java [20:74]
public PrimitiveDataset execute(PrimitiveDataset input, LinkedHashMap<String, Object> params) {
// Validate the input parameters and input column schema
validateInput(input, params);
int[] inIds = input.getIntColumn(0);
String[] inValues = input.getStringColumn(1);
int rowCount = inValues.length;
String regexExpr = (String)params.get("regexExpr");
expr = Pattern.compile(regexExpr);
System.out.println("regex expression: " + regexExpr);
// Lists to store the output data
LinkedList<Integer> outIds = new LinkedList<Integer>();
LinkedList<String> outValues = new LinkedList<String>();
// Evaluate each row
for(int i = 0; i < rowCount; i++) {
if (check(inValues[i])) {
outIds.add(inIds[i]);
outValues.add(inValues[i]);
}
}
int outputRowCount = outValues.size();
int[] idOutputCol = new int[outputRowCount];
String[] valueOutputCol = new String[outputRowCount];
// Convert the list of output columns to arrays
outValues.toArray(valueOutputCol);
ListIterator<Integer> it = outIds.listIterator(0);
int rowId = 0;
System.out.println("Output data:");
while (it.hasNext()) {
idOutputCol[rowId] = it.next().intValue();
System.out.println("ID: " + idOutputCol[rowId] + " Value: " + valueOutputCol[rowId]);
rowId++;
}
// Construct the output dataset
PrimitiveDataset output = new PrimitiveDataset();
output.addColumnMetadata(0, "ID", java.sql.Types.INTEGER, 0, 0);
output.addColumnMetadata(1, "Text", java.sql.Types.NVARCHAR, 0, 0);
output.addIntColumn(0, idOutputCol, null);
output.addStringColumn(1, valueOutputCol);
return output;
}