/** Creates an array of {@link RexLocalRef} objects, one for each field of a given rowtype. */
public static RexLocalRef[] toLocalRefs(RelDataType rowType) {
final RelDataTypeField[] fields = rowType.getFields();
final RexLocalRef[] refs = new RexLocalRef[fields.length];
for (int i = 0; i < refs.length; i++) {
refs[i] = new RexLocalRef(i, fields[i].getType());
}
return refs;
}
/**
* Creates an array of {@link RexInputRef} objects, one for each field of a given rowtype,
* according to a permutation.
*
* @param args Permutation
* @param rowType Input row type
* @return Array of input refs
*/
public static RexInputRef[] toInputRefs(int[] args, RelDataType rowType) {
final RelDataTypeField[] fields = rowType.getFields();
final RexInputRef[] rexNodes = new RexInputRef[args.length];
for (int i = 0; i < args.length; i++) {
int fieldOrdinal = args[i];
rexNodes[i] = new RexInputRef(fieldOrdinal, fields[fieldOrdinal].getType());
}
return rexNodes;
}
/**
* Generates a cast from one row type to another
*
* @param rexBuilder RexBuilder to use for constructing casts
* @param lhsRowType target row type
* @param rhsRowType source row type; fields must be 1-to-1 with lhsRowType, in same order
* @return cast expressions
*/
public static RexNode[] generateCastExpressions(
RexBuilder rexBuilder, RelDataType lhsRowType, RelDataType rhsRowType) {
int n = rhsRowType.getFieldCount();
assert n == lhsRowType.getFieldCount()
: "field count: lhs [" + lhsRowType + "] rhs [" + rhsRowType + "]";
RexNode[] rhsExps = new RexNode[n];
for (int i = 0; i < n; ++i) {
rhsExps[i] = rexBuilder.makeInputRef(rhsRowType.getFields()[i].getType(), i);
}
return generateCastExpressions(rexBuilder, lhsRowType, rhsExps);
}
/**
* Returns whether the type of an array of expressions is compatible with a struct type.
*
* @param exprs Array of expressions
* @param type Type
* @param fail Whether to fail if there is a mismatch
* @return Whether every expression has the same type as the corresponding member of the struct
* type
* @see RelOptUtil#eq(String, RelDataType, String, RelDataType, boolean)
*/
public static boolean compatibleTypes(RexNode[] exprs, RelDataType type, boolean fail) {
final RelDataTypeField[] fields = type.getFields();
if (exprs.length != fields.length) {
assert !fail : "rowtype mismatches expressions";
return false;
}
for (int i = 0; i < fields.length; i++) {
final RelDataType exprType = exprs[i].getType();
final RelDataType fieldType = fields[i].getType();
if (!RelOptUtil.eq("type1", exprType, "type2", fieldType, fail)) {
return false;
}
}
return true;
}
/**
* Generates a cast for a row type.
*
* @param rexBuilder RexBuilder to use for constructing casts
* @param lhsRowType target row type
* @param rhsExps expressions to be cast
* @return cast expressions
*/
public static RexNode[] generateCastExpressions(
RexBuilder rexBuilder, RelDataType lhsRowType, RexNode[] rhsExps) {
RelDataTypeField[] lhsFields = lhsRowType.getFields();
final int fieldCount = lhsFields.length;
RexNode[] castExps = new RexNode[fieldCount];
assert fieldCount == rhsExps.length;
for (int i = 0; i < fieldCount; ++i) {
RelDataTypeField lhsField = lhsFields[i];
RelDataType lhsType = lhsField.getType();
RelDataType rhsType = rhsExps[i].getType();
if (lhsType.equals(rhsType)) {
castExps[i] = rhsExps[i];
} else {
castExps[i] = rexBuilder.makeCast(lhsType, rhsExps[i]);
}
}
return castExps;
}
/**
* Returns whether the leading edge of a given array of expressions is wholly {@link RexInputRef}
* objects with types corresponding to the underlying datatype.
*/
public static boolean containIdentity(RexNode[] exprs, RelDataType rowType, boolean fail) {
final RelDataTypeField[] fields = rowType.getFields();
if (exprs.length < fields.length) {
assert !fail : "exprs/rowType length mismatch";
return false;
}
for (int i = 0; i < fields.length; i++) {
if (!(exprs[i] instanceof RexInputRef)) {
assert !fail : "expr[" + i + "] is not a RexInputRef";
return false;
}
RexInputRef inputRef = (RexInputRef) exprs[i];
if (inputRef.getIndex() != i) {
assert !fail : "expr[" + i + "] has ordinal " + inputRef.getIndex();
return false;
}
if (!RelOptUtil.eq("type1", exprs[i].getType(), "type2", fields[i].getType(), fail)) {
return false;
}
}
return true;
}
