Damian Steer wrote:
On 11 Mar 2011, at 12:30, Damian Steer wrote:
The only difference between Q3 and Q1|Q2 is that we have a different
variable name (i.e. ?y instead of ?v). The queries are different, but
they are "equivalent": they are structurally the same, only variable
names are different.
I don't think it handles this (but I may be wrong).
Ah, Op#equalTo(Op other, NodeIsomorphismMap labelMap) would do that, once you
have the mapping.
Thank you Damian, I'll try this.
In the meantime, this is what I came up with (before reading your email):
Op op1 = Algebra.compile(q1);
Op op3 = Algebra.compile(q3);
Item it1 = SSE.parse(op1.toString());
it1 = ItemTransformer.transform(new RenameVariablesItemTransform(), it1);
Item it3 = SSE.parse(op3.toString());
it3 = ItemTransformer.transform(new RenameVariablesItemTransform(), it3);
op1 = Algebra.parse(it1);
op3 = Algebra.parse(it3);
assertEquals(op1, op3);
The RenameVariablesItemTransform is:
class RenameVariablesItemTransform extends ItemTransformBase {
private HashMap<String, String> varNamesMapping = new HashMap<String,
String>();
private int count = 0;
@Override
public Item transform(Item item, Node node) {
if ( node.isVariable() ) {
if ( ! varNamesMapping.containsKey(node.toString()) ) {
varNamesMapping.put(node.toString(), "v_" + count++);
}
Var var = Var.alloc(varNamesMapping.get(node.toString()));
return Item.createNode(var, item.getLine(), item.getColumn()) ;
} else {
return Item.createNode(node, item.getLine(), item.getColumn()) ;
}
}
}
Not an elegant solution, but it allows me to find (and count) "equivalent"
queries
in my log files. :-)
Paolo
Damian
