/** Create int-based (non-nested) field position keys on a tuple type. */
public ExpressionKeys(int[] keyPositions, TypeInformation<T> type, boolean allowEmpty) {
if (!type.isTupleType() || !(type instanceof CompositeType)) {
throw new InvalidProgramException(
"Specifying keys via field positions is only valid "
+ "for tuple data types. Type: "
+ type);
}
if (type.getArity() == 0) {
throw new InvalidProgramException(
"Tuple size must be greater than 0. Size: " + type.getArity());
}
if (!allowEmpty && (keyPositions == null || keyPositions.length == 0)) {
throw new IllegalArgumentException("The grouping fields must not be empty.");
}
this.keyFields = new ArrayList<>();
if (keyPositions == null || keyPositions.length == 0) {
// use all tuple fields as key fields
keyPositions = createIncrIntArray(type.getArity());
} else {
rangeCheckFields(keyPositions, type.getArity() - 1);
}
Preconditions.checkArgument(
keyPositions.length > 0, "Grouping fields can not be empty at this point");
// extract key field types
CompositeType<T> cType = (CompositeType<T>) type;
this.keyFields = new ArrayList<>(type.getTotalFields());
// for each key position, find all (nested) field types
String[] fieldNames = cType.getFieldNames();
ArrayList<FlatFieldDescriptor> tmpList = new ArrayList<>();
for (int keyPos : keyPositions) {
tmpList.clear();
// get all flat fields
cType.getFlatFields(fieldNames[keyPos], 0, tmpList);
// check if fields are of key type
for (FlatFieldDescriptor ffd : tmpList) {
if (!ffd.getType().isKeyType()) {
throw new InvalidProgramException(
"This type (" + ffd.getType() + ") cannot be used as key.");
}
}
this.keyFields.addAll(tmpList);
}
}
