| /* |
| * 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.pig.builtin; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| |
| import org.apache.pig.FilterFunc; |
| import org.apache.pig.PigException; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.Tuple; |
| |
| |
| /** |
| * Determine whether a bag or map is empty. |
| */ |
| public class IsEmpty extends FilterFunc { |
| |
| @Override |
| public Boolean exec(Tuple input) throws IOException { |
| try { |
| Object values = input.get(0); |
| if (values instanceof DataBag) |
| return ((DataBag)values).size() == 0; |
| else if (values instanceof Map) |
| return ((Map)values).size() == 0; |
| else { |
| int errCode = 2102; |
| String msg = "Cannot test a " + |
| DataType.findTypeName(values) + " for emptiness."; |
| throw new ExecException(msg, errCode, PigException.BUG); |
| } |
| } catch (ExecException ee) { |
| throw ee; |
| } |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| } |