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Rebalance checkConnected()

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AtomicBoolean forces the enclosed boolean to be cache-aligned,
needlessly hitting a cacheline. Since we only flip state only once,
when the connection is severed, we can turn this into a volatile
boolean.

Doing that is costing us a synchronized close(), but that is perfectly
acceptable, as that is called only once.

Change-Id: I76fda3d3f65a5f800e7d3970b0b8fe99fb3e8b6d
Signed-off-by: Robert Varga <nite@hq.sk>
This commit is contained in:
Robert Varga
2016-02-14 02:10:18 +01:00
committed by Gerrit Code Review
parent 9b7057fe36
commit e1cfcbcda6
1 changed files with 9 additions and 8 deletions
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17
vpp-japi/japi/org/openvpp/vppjapi/vppConn.java
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@ -23,7 +23,6 @@ import java.nio.file.StandardCopyOption;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import org.openvpp.vppjapi.vppVersion;
import org.openvpp.vppjapi.vppInterfaceDetails;
@ -39,8 +38,8 @@ public class vppConn implements AutoCloseable {
static {
try {
loadLibrary();
} catch (IOException | RuntimeException e) {
System.out.printf ("Can't find vpp jni library: %s\n", LIBNAME);
} catch (Exception e) {
System.out.printf("Can't find vpp jni library: %s\n", LIBNAME);
throw new ExceptionInInitializerError(e);
}
}
@ -67,7 +66,7 @@ public class vppConn implements AutoCloseable {
private static void loadLibrary() throws IOException {
try (final InputStream is = vppConn.class.getResourceAsStream('/' + LIBNAME)) {
if (is == null) {
throw new IOException(String.format("Failed to open library resource %s",
throw new IOException(String.format("Failed to open library resource %s",
LIBNAME));
}
loadStream(is);
@ -75,8 +74,8 @@ public class vppConn implements AutoCloseable {
}
private static vppConn currentConnection = null;
private final AtomicBoolean disconnected = new AtomicBoolean(false);
private final String clientName;
private volatile boolean disconnected = false;
// Hidden on purpose to prevent external instantiation
vppConn(final String clientName) throws IOException {
@ -97,8 +96,10 @@ public class vppConn implements AutoCloseable {
}
@Override
public final void close() {
if (disconnected.compareAndSet(false, true)) {
public synchronized final void close() {
if (!disconnected) {
disconnected = true;
synchronized (vppConn.class) {
clientDisconnect();
currentConnection = null;
@ -112,7 +113,7 @@ public class vppConn implements AutoCloseable {
* @throws IllegalStateException if this instance was disconnected.
*/
protected final void checkConnected() {
if (disconnected.get()) {
if (disconnected) {
throw new IllegalStateException("Disconnected client " + clientName);
}
}