1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package com.github.dexecutor.executor;
19
20 import java.io.Writer;
21
22 /**
23 * Main Interface for Dexecutor framework, It provides api to build the graph and and to kick off the execution.
24 *
25 * @author Nadeem Mohammad
26 *
27 * @see {@link DefaultDependentTasksExecutor}
28 *
29 * @param <T> Type of Node/Task ID
30 * @param <R> Type of Node/Task result
31 */
32 public interface DependentTasksExecutor<T extends Comparable<T>> {
33 /**
34 * Add a node as independent, it does not require any dependent node
35 *
36 * @param nodeValue
37 */
38 void addIndependent(final T nodeValue);
39 /**
40 * <p>Add Two dependent nodes into the graph, creating the nodes if not already present </p>
41 * <p><code>evalFirstValue </code> would be executed first and then <code> evalAfterValue </code> </p>
42 *
43 * @param evalFirstValue
44 * @param evalAfterValue
45 */
46 void addDependency(final T evalFirstValue, final T evalAfterValue);
47 /**
48 * Adds the node as dependent on all leaf nodes (at the time of adding), meaning all leaf nodes would be evaluated first and then the given node
49 *
50 * @param nodeValue
51 */
52 void addAsDependentOnAllLeafNodes(final T nodeValue);
53 /**
54 * Adds the node as dependency to all initial nodes (at the time of adding), meaning this given node would be evaluated first and then all initial nodes would run in parallel
55 *
56 * @param nodeValue
57 */
58 void addAsDependencyToAllInitialNodes(final T nodeValue);
59 /**
60 * Kicks off the execution of the nodes based on the dependency graph constructed, using {@code addDepen***} apis
61 *
62 * @param behavior
63 */
64 void execute(final ExecutionBehavior behavior);
65
66 /**
67 * Prints the graph into the writer
68 *
69 * @param writer
70 */
71 void print(final Writer writer);
72
73 /**
74 * Defines the execution behavior of the tasks
75 * <ul>
76 * <li>
77 * <code>TERMINATING </code> : Whole tasks execution would come to an end after the execution is thrown
78 * </li>
79 * <li>
80 * <code>NON_TERMINATING</code> : Tasks execution wont come to halt after an exception is thrown out of task
81 * </li>
82 * <li>
83 * <code>RETRY_ONCE_TERMINATING</code> : A retry would be attempted after an exception is thrown, and then if the execption is thrown again, the tasks execution would stop
84 * </li>
85 *
86 * </ul>
87 *
88 * @author Nadeem Mohammad
89 *
90 */
91 enum ExecutionBehavior {
92 TERMINATING, NON_TERMINATING, RETRY_ONCE_TERMINATING;
93 }
94 }