protected ExpQuery(
Type resultType, VarDeclList elemVarDecls, Expression rangeExp, Expression queryExp)
throws ExpInvalidException {
super(resultType, rangeExp, queryExp);
fElemVarDecls = elemVarDecls;
fRangeExp = rangeExp;
fQueryExp = queryExp;
// type of rangeExp must be a subtype of Collection, i.e. Set,
// Sequence or Bag
if (!fRangeExp.type().isCollection(false))
throw new ExpInvalidException(
"Range expression must be of type " + "`Collection', found `" + fRangeExp.type() + "'.");
// assert that declard element variables are equal or
// supertypes of range element type
Type rangeElemType = ((CollectionType) fRangeExp.type()).elemType();
for (int i = 0; i < fElemVarDecls.size(); i++) {
VarDecl vd = fElemVarDecls.varDecl(i);
if (!rangeElemType.isSubtypeOf(vd.type()))
throw new ExpInvalidException(
"Type `"
+ vd.type()
+ "' of range variable `"
+ vd.name()
+ "' does not match type `"
+ rangeElemType
+ "' of collection elements.");
}
}
/** Evaluate isUnique expression. */
protected final Value evalIsUnique(EvalContext ctx) {
// evaluate range
Value v = fRangeExp.eval(ctx);
if (v.isUndefined()) return UndefinedValue.instance;
CollectionValue rangeVal = (CollectionValue) v;
// collect values for finding duplicates
Set<Value> values = new HashSet<Value>();
// loop over range elements
for (Value elemVal : rangeVal) {
// bind element variable to range element, if variable was
// declared
if (!fElemVarDecls.isEmpty()) ctx.pushVarBinding(fElemVarDecls.varDecl(0).name(), elemVal);
// evaluate collect expression
Value val = fQueryExp.eval(ctx);
if (!fElemVarDecls.isEmpty()) ctx.popVarBinding();
// stop if duplicate element is found
if (values.contains(val)) return BooleanValue.FALSE;
else values.add(val);
}
// result is true if no duplicates where found
return BooleanValue.TRUE;
}
/** Evaluate collect expressions. */
protected final Value evalCollectNested(EvalContext ctx) {
// evaluate range
Value v = fRangeExp.eval(ctx);
if (v.isUndefined()) return UndefinedValue.instance;
CollectionValue rangeVal = (CollectionValue) v;
// prepare result value
ArrayList<Value> resValues = new ArrayList<Value>();
// loop over range elements
for (Value elemVal : rangeVal) {
// bind element variable to range element, if variable was
// declared
if (!fElemVarDecls.isEmpty()) ctx.pushVarBinding(fElemVarDecls.varDecl(0).name(), elemVal);
// evaluate collect expression
Value val = fQueryExp.eval(ctx);
// add element to result
resValues.add(val);
if (!fElemVarDecls.isEmpty()) ctx.popVarBinding();
}
// result is collection with mapped values
if (fRangeExp.type().isSequence() || fRangeExp.type().isOrderedSet())
return new SequenceValue(fQueryExp.type(), resValues);
else return new BagValue(fQueryExp.type(), resValues);
}
@Override
public StringBuilder toString(StringBuilder sb) {
fRangeExp.toString(sb);
sb.append("->").append(this.name()).append("(");
if (!fElemVarDecls.isEmpty()) {
fElemVarDecls.toString(sb);
sb.append(" | ");
}
fQueryExp.toString(sb);
return sb.append(")");
}
/** Evaluate sortedBy expressions. */
protected final Value evalSortedBy(EvalContext ctx) {
// evaluate range
Value v = fRangeExp.eval(ctx);
if (v.isUndefined()) return UndefinedValue.instance;
CollectionValue rangeVal = (CollectionValue) v;
ArrayList<KeyValPair> keyValList = new ArrayList<KeyValPair>();
// loop over range elements
for (Value elemVal : rangeVal) {
// bind element variable to range element, if variable was
// declared
if (!fElemVarDecls.isEmpty()) ctx.pushVarBinding(fElemVarDecls.varDecl(0).name(), elemVal);
// evaluate sortedBy expression and store the result as a
// key together with elemVal
Value key = fQueryExp.eval(ctx);
keyValList.add(new KeyValPair(key, elemVal));
if (!fElemVarDecls.isEmpty()) ctx.popVarBinding();
}
// sort elements by key
Collections.sort(
keyValList,
new Comparator<KeyValPair>() {
public int compare(KeyValPair o1, KeyValPair o2) {
return o1.fKey.compareTo(o2.fKey);
}
});
// drop the keys from the list
ListIterator<KeyValPair> listIter = keyValList.listIterator();
Collection<Value> result = new ArrayList<Value>(keyValList.size());
while (listIter.hasNext()) {
KeyValPair kvp = listIter.next();
result.add(kvp.fElem);
}
Type rangeElemType = ((CollectionType) fRangeExp.type()).elemType();
return new SequenceValue(rangeElemType, result);
}
/** Evaluate select and reject expressions. */
protected final Value evalSelectOrReject(EvalContext ctx, boolean doSelect) {
// evaluate range
Value v = fRangeExp.eval(ctx);
if (v.isUndefined()) return UndefinedValue.instance;
CollectionValue rangeVal = (CollectionValue) v;
// prepare result value
ArrayList<Value> resValues = new ArrayList<Value>();
Type elemType = rangeVal.elemType();
if (!rangeVal.type().isInstantiableCollection())
throw new RuntimeException("rangeVal is not of collection type: " + rangeVal.type());
// loop over range elements
for (Value elemVal : rangeVal) {
// bind element variable to range element, if variable was
// declared
if (!fElemVarDecls.isEmpty()) ctx.pushVarBinding(fElemVarDecls.varDecl(0).name(), elemVal);
// evaluate select expression
Value queryVal = fQueryExp.eval(ctx);
// undefined query values default to false
if (queryVal.isUndefined()) queryVal = BooleanValue.FALSE;
if (((BooleanValue) queryVal).value() == doSelect) resValues.add(elemVal);
if (!fElemVarDecls.isEmpty()) ctx.popVarBinding();
}
CollectionValue res;
if (rangeVal.type().isSet()) res = new SetValue(elemType, resValues);
else if (rangeVal.type().isSequence()) res = new SequenceValue(elemType, resValues);
else if (rangeVal.type().isBag()) res = new BagValue(elemType, resValues);
else if (rangeVal.type().isOrderedSet()) res = new OrderedSetValue(elemType, resValues);
else {
// should not happen
throw new RuntimeException("rangeVal is not of collection type: " + rangeVal.type());
}
// result is collection with selected/rejected values
return res;
}
private final boolean evalExistsOrForAll0(
int nesting, CollectionValue rangeVal, EvalContext ctx, boolean doExists) {
// loop over range elements
boolean res = !doExists;
for (Value elemVal : rangeVal) {
// bind element variable to range element, if variable was
// declared
if (!fElemVarDecls.isEmpty())
ctx.pushVarBinding(fElemVarDecls.varDecl(nesting).name(), elemVal);
if (!fElemVarDecls.isEmpty() && nesting < fElemVarDecls.size() - 1) {
// call recursively to iterate over range while
// assigning each value to each element variable
// eventually
if (res != doExists) res = evalExistsOrForAll0(nesting + 1, rangeVal, ctx, doExists);
else
// don't change the result value when expression is true
// (exists) or
// false (forAll) and continue iteration
evalExistsOrForAll0(nesting + 1, rangeVal, ctx, doExists);
} else {
// evaluate predicate expression
Value queryVal = fQueryExp.eval(ctx);
// undefined query values default to false
if (queryVal.isUndefined()) queryVal = BooleanValue.FALSE;
// don't change the result value when expression is true
// (exists) or
// false (forAll) and continue iteration
if (res != doExists && ((BooleanValue) queryVal).value() == doExists) res = doExists;
}
if (!fElemVarDecls.isEmpty()) ctx.popVarBinding();
}
return res;
}
