| /* |
| * 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.drill.exec.expr; |
| |
| import java.util.Collections; |
| import java.util.Iterator; |
| |
| import org.apache.drill.common.expression.ExpressionPosition; |
| import org.apache.drill.common.expression.LogicalExpression; |
| import org.apache.drill.common.expression.visitors.ExprVisitor; |
| import org.apache.drill.common.types.TypeProtos.MajorType; |
| import org.apache.drill.exec.expr.ClassGenerator.HoldingContainer; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Wrapper around a representation of a "Holder" to represent that |
| * Holder as an expression. Whether this expression represents a |
| * declaration, initialization, or reference (use) of the holder |
| * depends on the visitor applied to this expression. |
| * <p> |
| * This expression class is a run-time implementation detail; it |
| * shows up in the "unknown" bucket within the visitor, where it |
| * must be parsed out using <code>instanceof</code> (or assumed.) |
| */ |
| public class HoldingContainerExpression implements LogicalExpression{ |
| static final Logger logger = LoggerFactory.getLogger(HoldingContainerExpression.class); |
| |
| final HoldingContainer container; |
| |
| public HoldingContainerExpression(HoldingContainer container) { |
| this.container = container; |
| } |
| |
| @Override |
| public Iterator<LogicalExpression> iterator() { |
| return Collections.emptyIterator(); |
| } |
| |
| @Override |
| public MajorType getMajorType() { |
| return container.getMajorType(); |
| } |
| |
| @Override |
| public <T, V, E extends Exception> T accept(ExprVisitor<T, V, E> visitor, V value) throws E { |
| return visitor.visitUnknown(this, value); |
| } |
| |
| public HoldingContainer getContainer() { |
| return container; |
| } |
| |
| @Override |
| public ExpressionPosition getPosition() { |
| return ExpressionPosition.UNKNOWN; |
| } |
| |
| @Override |
| public int getSelfCost() { |
| return 0; // TODO |
| } |
| |
| @Override |
| public int getCumulativeCost() { |
| return 0; // TODO |
| } |
| |
| @Override |
| public String toString() { |
| return container.toString(); |
| } |
| } |