Use StaticException class in jetty-util for websocket flushers.

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>
jetty · Jun 10, 2022 · 805c8ee · 805c8ee
1 parent 657222f
commit 805c8ee
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Showing 4 changed files with 15 additions and 13 deletions.
diff --git a/...tion/SentinelWebSocketCloseException.java → ...g/eclipse/jetty/util/StaticException.java b/...tion/SentinelWebSocketCloseException.java → ...g/eclipse/jetty/util/StaticException.java
@@ -11,22 +11,24 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.websocket.core.exception;
+package org.eclipse.jetty.util;
 
 /**
- * Suppressed exceptions are disabled for this implementation,
+ * This exception can safely be stored in a static variable as suppressed exceptions are disabled,
  * meaning calling {@link #addSuppressed(Throwable)} has no effect.
- * This means instances of {@link SentinelWebSocketCloseException} are suitable to be kept as static fields.
+ * This prevents potential memory leaks where a statically-stored exception would accumulate
+ * suppressed exceptions added to them.
  */
-public class SentinelWebSocketCloseException extends Exception
+public class StaticException extends Exception
 {
-    public SentinelWebSocketCloseException()
+    public StaticException()
     {
         this(null);
     }
 
-    public SentinelWebSocketCloseException(String message)
+    public StaticException(String message)
     {
+        // Make sure to call the super constructor that disables suppressed exception.
         super(message, null, false, true);
     }
-}
+}
diff --git a/...core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/DemandingFlusher.java b/...core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/DemandingFlusher.java
@@ -20,10 +20,10 @@
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.CountingCallback;
 import org.eclipse.jetty.util.IteratingCallback;
+import org.eclipse.jetty.util.StaticException;
 import org.eclipse.jetty.websocket.core.Extension;
 import org.eclipse.jetty.websocket.core.Frame;
 import org.eclipse.jetty.websocket.core.IncomingFrames;
-import org.eclipse.jetty.websocket.core.exception.SentinelWebSocketCloseException;
 
 /**
  * <p>This flusher can be used to mutated and fragment {@link Frame}s and forwarded them on towards the application using the
@@ -39,7 +39,7 @@
  */
 public abstract class DemandingFlusher extends IteratingCallback implements DemandChain
 {
-    private static final Throwable SENTINEL_CLOSE_EXCEPTION = new SentinelWebSocketCloseException();
+    private static final Throwable SENTINEL_CLOSE_EXCEPTION = new StaticException("Closed");
 
     private final IncomingFrames _emitFrame;
     private final AtomicLong _demand = new AtomicLong();

diff --git a/...ket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java b/...ket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java
@@ -29,13 +29,13 @@
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.IteratingCallback;
+import org.eclipse.jetty.util.StaticException;
 import org.eclipse.jetty.util.TypeUtil;
 import org.eclipse.jetty.util.thread.AutoLock;
 import org.eclipse.jetty.util.thread.Scheduler;
 import org.eclipse.jetty.websocket.core.CloseStatus;
 import org.eclipse.jetty.websocket.core.Frame;
 import org.eclipse.jetty.websocket.core.OpCode;
-import org.eclipse.jetty.websocket.core.exception.SentinelWebSocketCloseException;
 import org.eclipse.jetty.websocket.core.exception.WebSocketException;
 import org.eclipse.jetty.websocket.core.exception.WebSocketWriteTimeoutException;
 import org.slf4j.Logger;
@@ -45,7 +45,7 @@ public class FrameFlusher extends IteratingCallback
 {
     public static final Frame FLUSH_FRAME = new Frame(OpCode.BINARY);
     private static final Logger LOG = LoggerFactory.getLogger(FrameFlusher.class);
-    private static final Throwable CLOSED_CHANNEL = new SentinelWebSocketCloseException();
+    private static final Throwable CLOSED_CHANNEL = new StaticException("Closed");
 
     private final AutoLock lock = new AutoLock();
     private final LongAdder messagesOut = new LongAdder();

diff --git a/...e-common/src/main/java/org/eclipse/jetty/websocket/core/internal/TransformingFlusher.java b/...e-common/src/main/java/org/eclipse/jetty/websocket/core/internal/TransformingFlusher.java
@@ -18,9 +18,9 @@
 
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.IteratingCallback;
+import org.eclipse.jetty.util.StaticException;
 import org.eclipse.jetty.util.thread.AutoLock;
 import org.eclipse.jetty.websocket.core.Frame;
-import org.eclipse.jetty.websocket.core.exception.SentinelWebSocketCloseException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -34,7 +34,7 @@
 public abstract class TransformingFlusher
 {
     private final Logger log = LoggerFactory.getLogger(this.getClass());
-    private static final Throwable SENTINEL_CLOSE_EXCEPTION = new SentinelWebSocketCloseException();
+    private static final Throwable SENTINEL_CLOSE_EXCEPTION = new StaticException("Closed");
 
     private final AutoLock lock = new AutoLock();
     private final Queue<FrameEntry> entries = new ArrayDeque<>();