1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.giraph.function.vertex;
19
20 import java.io.Serializable;
21
22 import org.apache.giraph.graph.Vertex;
23 import org.apache.hadoop.io.Writable;
24 import org.apache.hadoop.io.WritableComparable;
25
26 /**
27 * Function:
28 * (vertex) -> T
29 *
30 * A class that can supply objects of a single type, when given a vertex.
31 *
32 * (doesn't extend Function<Vertex<I, V, E>, T>,
33 * because of different method names)
34 *
35 * @param <I> Vertex id type
36 * @param <V> Vertex value type
37 * @param <E> Edge value type
38 * @param <T> Result type
39 */
40 @SuppressWarnings("rawtypes")
41 public interface SupplierFromVertex<I extends WritableComparable,
42 V extends Writable, E extends Writable, T> extends Serializable {
43 /**
44 * Retrieves an instance of the appropriate type, given a vertex.
45 * The returned object may or may not be a new instance,
46 * depending on the implementation.
47 *
48 * @param vertex Vertex
49 * @return result
50 */
51 T get(Vertex<I, V, E> vertex);
52 }