PLT Utilities Test Coverage (plt-20120304-r5436)

Clover coverage report - PLT Utilities Test Coverage (plt-20120304-r5436)

Coverage timestamp: Sat Mar 3 2012 22:01:56 CST

FRAMES NO FRAMES

file stats:	LOC:	174		Methods:	15
	NCLOC:	86		Classes:	3

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Methods

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PollingTaskController.java

1		/BEGIN_COPYRIGHT_BLOCK
2
3		PLT Utilities BSD License
4
5		Copyright (c) 2007-2010 JavaPLT group at Rice University
6		All rights reserved.
7
8		Developed by: Java Programming Languages Team
9		Rice University
10		http://www.cs.rice.edu/~javaplt/
11
12		Redistribution and use in source and binary forms, with or without modification, are permitted
13		provided that the following conditions are met:
14
15		- Redistributions of source code must retain the above copyright notice, this list of conditions
16		and the following disclaimer.
17		- Redistributions in binary form must reproduce the above copyright notice, this list of
18		conditions and the following disclaimer in the documentation and/or other materials provided
19		with the distribution.
20		- Neither the name of the JavaPLT group, Rice University, nor the names of the library's
21		contributors may be used to endorse or promote products derived from this software without
22		specific prior written permission.
23
24		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
25		IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
26		FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND
27		CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28		DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29		DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
30		IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31		OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32
33		END_COPYRIGHT_BLOCK/
34
35		package edu.rice.cs.plt.concurrent;
36
37		import java.util.concurrent.ExecutionException;
38		import java.util.concurrent.TimeUnit;
39		import java.util.concurrent.TimeoutException;
40
41		import edu.rice.cs.plt.collect.ListenerSet;
42		import edu.rice.cs.plt.lambda.LazyRunnable;
43
44		/**
45		* <p>A TaskController for tasks that are run without any facility for executing code when the task
46		* is complete — instead, the controller must either block, poll for the task's current status.
47		* When most of the controller's methods are invoked, the current status is polled before proceeding;
48		* operations depending on completion block ({@link #finishListeners()} are handled by blocking in a new
49		* daemon thread).</p>
50		*
51		* <p>To implement a concrete instance, a subclass must provide {@link #doStart}, {@link #doStop},
52		* {@link #update}, {@link #finish}, and, optionally, {@link #discard}.</p>
53		*/
54		public abstract class PollingTaskController<R> extends TaskController<R> {
55
56		private final LazyRunnable _startDaemon;
57
58	0	protected PollingTaskController() {
59		// a daemon thread is started only if necessary -- if there are no listeners, we can just wait
60		// for the user to check on the current status
61	0	_startDaemon = new LazyRunnable(new Runnable() {
62	0	public void run() {
63	0	Thread t = new Thread("PollingTaskController daemon") {
64	0	public void run() {
65	0	try { finish(); }
66		catch (InterruptedException e) { /* if interrupted, just stop */ }
67		}
68		};
69	0	t.setDaemon(true);
70	0	t.start();
71		}
72		});
73		}
74
75		/**
76		* Access the ListenerSet responding to the completion of computation. The first time this method
77		* is invoked, a daemon thread is started that will wait for computation to complete (otherwise,
78		* any registered listeners will not run until the task is manually polled).
79		*/
80	0	public ListenerSet<R>.Sink finishListeners() {
81	0	_startDaemon.run();
82	0	return super.finishListeners();
83		}
84
85
86
87		/**
88		* Check the current status and call the appropriate method if the task is complete. This method
89		* is invoked frequently and should not block.
90		*/
91		protected abstract void update();
92
93		/**
94		* Block until the task is complete or this thread is interrupted. Must not return until after one
95		* of the completion methods are called.
96		*/
97		protected abstract void finish() throws InterruptedException;
98
99		/**
100		* Block until the task is complete, this thread is interrupted, or the given timeout is reached. Must
101		* not return until after one of the completion methods are called.
102		*/
103		protected abstract void finish(long timeout, TimeUnit unit) throws InterruptedException, TimeoutException;
104
105	0	protected RunningState runningState() { return new PollingRunningState(); }
106
107		/**
108		* RunningState variant based on a PollingRunner. Extends RunningState to allow it to be
109		* recognized as that type.
110		*/
111		protected class PollingRunningState extends RunningState {
112	0	public Status status() {
113	0	update();
114	0	return (state.get() == this) ? Status.RUNNING : state.get().status();
115		}
116	0	public void start() {
117	0	update();
118	0	if (state.get() != this) { state.get().start(); }
119		}
120	0	public R get() throws InterruptedException, ExecutionException {
121	0	finish();
122	0	if (!isDone()) { throw new IllegalStateException("PollingTaskController returned without finishing"); }
123	0	return state.get().get();
124		}
125	0	public R get(long timeout, TimeUnit u) throws InterruptedException, ExecutionException, TimeoutException {
126	0	finish(timeout, u);
127	0	if (!isDone()) { throw new IllegalStateException("PollingTaskController returned without finishing"); }
128	0	return state.get().get();
129		}
130	0	public boolean cancel(boolean stopRunning) {
131	0	update();
132	0	if (state.get() == this) {
133	0	if (stopRunning) {
134	0	if (state.compareAndSet(this, new PollingCancelingState())) { doStop(); return true; }
135	0	else { return state.get().cancel(stopRunning); }
136		}
137	0	else { return false; }
138		}
139	0	else { return state.get().cancel(stopRunning); }
140		}
141		}
142
143		/**
144		* CancelingState variant based on a PollingRunner. Extends Canceling to allow it to be
145		* recognized as that type. (A lot of code is duplicated from PollingRunningState, but that
146		* seems inevitable without overhauling the design to use interfaces to identify different
147		* kinds of states.)
148		*/
149		protected class PollingCancelingState extends CancelingState {
150	0	public void start() {
151	0	update();
152	0	if (state.get() != this) { state.get().start(); }
153		}
154	0	public Status status() {
155	0	update();
156	0	return (state.get() == this) ? Status.RUNNING : state.get().status();
157		}
158	0	public boolean cancel(boolean stopRunning) {
159	0	update();
160	0	return (state.get() == this) ? stopRunning : state.get().cancel(stopRunning);
161		}
162	0	public R get() throws InterruptedException, ExecutionException {
163	0	finish();
164	0	if (!isDone()) { throw new IllegalStateException("PollingRunner returned without finishing"); }
165	0	return state.get().get();
166		}
167	0	public R get(long timeout, TimeUnit u) throws InterruptedException, ExecutionException, TimeoutException {
168	0	finish(timeout, u);
169	0	if (!isDone()) { throw new IllegalStateException("PollingRunner returned without finishing"); }
170	0	return state.get().get();
171		}
172		}
173
174		}