/*
* Licensed 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 com.facebook.presto.sql.util;
import com.facebook.presto.sql.tree.DefaultTraversalVisitor;
import com.facebook.presto.sql.tree.Node;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;
import java.util.Spliterators;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
public class AstUtils
{
public static boolean nodeContains(Node node, Node subNode)
{
return new DefaultTraversalVisitor<Boolean, AtomicBoolean>()
{
@Override
public Boolean process(Node node, AtomicBoolean findResultHolder)
{
if (!findResultHolder.get()) {
if (node == subNode) {
findResultHolder.set(true);
}
else {
super.process(node, findResultHolder);
}
}
return findResultHolder.get();
}
}.process(node, new AtomicBoolean(false));
}
public static Stream<Node> preOrder(Node node)
{
return StreamSupport.stream(Spliterators.spliteratorUnknownSize(new PreOrderIterator(node), 0), false);
}
private static final class PreOrderIterator
implements Iterator<Node>
{
private final Deque<Node> remaining = new ArrayDeque<>();
public PreOrderIterator(Node node)
{
remaining.push(node);
}
@Override
public boolean hasNext()
{
return remaining.size() > 0;
}
@Override
public Node next()
{
Node node = remaining.pop();
node.getChildren().forEach(remaining::push);
return node;
}
}
private AstUtils() {}
}