io.trino.sql.planner.ConnectorExpressions Maven / Gradle / Ivy
/*
* 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 io.trino.sql.planner;
import com.google.common.graph.SuccessorsFunction;
import com.google.common.graph.Traverser;
import io.trino.spi.expression.ConnectorExpression;
import io.trino.spi.expression.Variable;
import java.util.List;
import java.util.stream.Stream;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.Streams.stream;
import static java.util.Objects.requireNonNull;
public final class ConnectorExpressions
{
private ConnectorExpressions() {}
public static List extractVariables(ConnectorExpression expression)
{
return preOrder(expression)
.filter(Variable.class::isInstance)
.map(Variable.class::cast)
.collect(toImmutableList());
}
public static Stream preOrder(ConnectorExpression expression)
{
return stream(
Traverser.forTree((SuccessorsFunction) ConnectorExpression::getChildren)
.depthFirstPreOrder(requireNonNull(expression, "expression is null")));
}
}