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*
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
/* @test
* @bug 7200742
* @key intermittent
* @summary Test that Selector doesn't spin when changing interest ops
*/
import java.net.*;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import static java.nio.channels.SelectionKey.*;
import java.io.IOException;
public class ChangingInterests {
static int OPS[] = { 0, OP_WRITE, OP_READ, (OP_WRITE|OP_READ) };
static String toOpsString(int ops) {
String s = "";
if ((ops & OP_READ) > 0)
s += "POLLIN";
if ((ops & OP_WRITE) > 0) {
if (s.length() > 0)
s += "|";
s += "POLLOUT";
}
if (s.length() == 0)
s = "0";
return "(" + s + ")";
}
static void write1(SocketChannel peer) throws IOException {
peer.write(ByteBuffer.wrap(new byte[1]));
// give time for other end to be readable
try {
Thread.sleep(50);
} catch (InterruptedException ignore) { }
}
static void drain(SocketChannel sc) throws IOException {
ByteBuffer buf = ByteBuffer.allocate(100);
int n;
while ((n = sc.read(buf)) > 0) {
buf.rewind();
}
}
/**
* Changes the given key's interest set from one set to another and then
* checks the selected key set and the key's channel.
*/
static void testChange(SelectionKey key, int from, int to) throws IOException {
Selector sel = key.selector();
assertTrue(sel.keys().size() == 1, "Only one channel should be registered");
// ensure that channel is registered with the "from" interest set
key.interestOps(from);
sel.selectNow();
sel.selectedKeys().clear();
// change to the "to" interest set
key.interestOps(to);
System.out.println("select...");
int selected = sel.selectNow();
System.out.println("" + selected + " channel(s) selected");
int expected = (to == 0) ? 0 : 1;
assertTrue(selected == expected, "Expected " + expected);
// check selected keys
for (SelectionKey k: sel.selectedKeys()) {
assertTrue(k == key, "Unexpected key selected");
boolean readable = k.isReadable();
boolean writable = k.isWritable();
System.out.println("key readable: " + readable);
System.out.println("key writable: " + writable);
if ((to & OP_READ) == 0) {
assertTrue(!readable, "Not expected to be readable");
} else {
assertTrue(readable, "Expected to be readable");
}
if ((to & OP_WRITE) == 0) {
assertTrue(!writable, "Not expected to be writable");
} else {
assertTrue(writable, "Expected to be writable");
}
sel.selectedKeys().clear();
}
}
/**
* Tests that given Selector's select method blocks.
*/
static void testForSpin(Selector sel) throws IOException {
System.out.println("Test for spin...");
long start = System.currentTimeMillis();
int count = 3;
while (count-- > 0) {
int selected = sel.select(1000);
System.out.println("" + selected + " channel(s) selected");
assertTrue(selected == 0, "Channel should not be selected");
}
long dur = System.currentTimeMillis() - start;
assertTrue(dur > 1000, "select was too short");
}
public static void main(String[] args) throws IOException {
InetAddress lh = InetAddress.getLocalHost();
// create loopback connection
ServerSocketChannel ssc =
ServerSocketChannel.open().bind(new InetSocketAddress(0));
final SocketChannel sc = SocketChannel.open();
sc.setOption(StandardSocketOptions.TCP_NODELAY, true);
sc.connect(new InetSocketAddress(lh, ssc.socket().getLocalPort()));
SocketChannel peer = ssc.accept();
peer.setOption(StandardSocketOptions.TCP_NODELAY, true);
sc.configureBlocking(false);
// ensure that channel "sc" is readable
write1(peer);
try (Selector sel = Selector.open()) {
SelectionKey key = sc.register(sel, 0);
sel.selectNow();
// test all transitions
for (int from: OPS) {
for (int to: OPS) {
System.out.println(toOpsString(from) + " -> " + toOpsString(to));
testChange(key, from, to);
// if the interst ops is now 0 then Selector should not spin
if (to == 0)
testForSpin(sel);
// if interest ops is now OP_READ then make non-readable
// and test that Selector does not spin.
if (to == OP_READ) {
System.out.println("Drain channel...");
drain(sc);
testForSpin(sel);
System.out.println("Make channel readable again");
write1(peer);
}
System.out.println();
}
}
} finally {
sc.close();
peer.close();
ssc.close();
}
}
static void assertTrue(boolean v, String msg) {
if (!v) throw new RuntimeException(msg);
}
}