| /* |
| * 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.lang.annotation.Documented; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.classification.InterfaceAudience; |
| import org.apache.pig.classification.InterfaceStability; |
| |
| /** |
| * An EvalFunc can annotated with an <code>OutputSchema</code> to |
| * tell Pig what the expected output is. This can be used in place |
| * of {@link EvalFunc#outputSchema(Schema)} |
| * <p> |
| * The default implementation of {@link EvalFunc#outputSchema(Schema)} |
| * will look at this annotation and return an interpreted schema, if the annotation is present. |
| * <p> |
| * Implementing a custom {@link EvalFunc#outputSchema(Schema)} will |
| * override the annotation (unless you deal with it explicitly, or by calling <code>super.outputSchema(schema)</code>). |
| * <p> |
| * Here's an example of a complex schema declared in an annotation: |
| * <code>@OutputSchema("y:bag{t:tuple(len:int,word:chararray)}")</code> |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Unstable |
| @Documented |
| @Retention(value=RetentionPolicy.RUNTIME) |
| public @interface OutputSchema { |
| String value(); |
| } |