/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.fpm.pfpgrowth;
import java.util.Iterator;
import java.util.Stack;
import org.apache.mahout.math.list.IntArrayList;
import com.google.common.collect.AbstractIterator;
import org.apache.mahout.common.Pair;
/**
* Generates a List of transactions view of Transaction Tree by doing Depth First Traversal on the tree
* structure
*/
@Deprecated
final class TransactionTreeIterator extends AbstractIterator<Pair<IntArrayList,Long>> {
private final Stack<int[]> depth = new Stack<int[]>();
private final TransactionTree transactionTree;
TransactionTreeIterator(TransactionTree transactionTree) {
this.transactionTree = transactionTree;
depth.push(new int[] {0, -1});
}
@Override
protected Pair<IntArrayList, Long> computeNext() {
if (depth.isEmpty()) {
return endOfData();
}
long sum;
int childId;
do {
int[] top = depth.peek();
while (top[1] + 1 == transactionTree.childCount(top[0])) {
depth.pop();
top = depth.peek();
}
if (depth.isEmpty()) {
return endOfData();
}
top[1]++;
childId = transactionTree.childAtIndex(top[0], top[1]);
depth.push(new int[] {childId, -1});
sum = 0;
for (int i = transactionTree.childCount(childId) - 1; i >= 0; i--) {
sum += transactionTree.count(transactionTree.childAtIndex(childId, i));
}
} while (sum == transactionTree.count(childId));
Iterator<int[]> it = depth.iterator();
it.next();
IntArrayList data = new IntArrayList();
while (it.hasNext()) {
data.add(transactionTree.attribute(it.next()[0]));
}
Pair<IntArrayList,Long> returnable = new Pair<IntArrayList,Long>(data, transactionTree.count(childId) - sum);
int[] top = depth.peek();
while (top[1] + 1 == transactionTree.childCount(top[0])) {
depth.pop();
if (depth.isEmpty()) {
break;
}
top = depth.peek();
}
return returnable;
}
}