/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.sql.optimizer.plan;
import com.foundationdb.ais.model.Table;
/** A subtree from the AIS.
* In other words, a group.
*/
public class TableTree extends TableTreeBase<TableNode>
{
private int nbranches;
protected TableNode createNode(Table table) {
return new TableNode(table, this);
}
/** Determine branch sharing.
* @return the number of branches. */
public int colorBranches() {
if (nbranches == 0)
nbranches = colorBranches(root, 0);
return nbranches;
}
private int colorBranches(TableNode node, int nbranches) {
long branches = 0;
for (TableNode child = node.getFirstChild();
child != null;
child = child.getNextSibling()) {
nbranches = colorBranches(child, nbranches);
// A parent is on the same branch as any child.
branches |= child.getBranches();
}
if (branches == 0) {
// The leaf of a new branch.
branches = (1L << nbranches++);
}
node.setBranches(branches);
return nbranches;
}
}