1 files changed, 69 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.log.stream/osgi/src/org/osgi/util/pushstream/PushEventConsumer.java b/bundles/org.eclipse.equinox.log.stream/osgi/src/org/osgi/util/pushstream/PushEventConsumer.java
new file mode 100644
index 000000000..43de152ae
--- /dev/null
+++ b/bundles/org.eclipse.equinox.log.stream/osgi/src/org/osgi/util/pushstream/PushEventConsumer.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) OSGi Alliance (2015). All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.osgi.util.pushstream;
+
+import org.osgi.annotation.versioning.ConsumerType;
+
+/**
+ * An Async Event Consumer asynchronously receives Data events until it receives
+ * either a Close or Error event.
+ * 
+ * @param <T>
+ *            The type for the event payload
+ */
+@ConsumerType
+@FunctionalInterface
+public interface PushEventConsumer<T> {
+
+	/**
+	 * If ABORT is used as return value, the sender should close the channel all
+	 * the way to the upstream source. The ABORT will not guarantee that no
+	 * more events are delivered since this is impossible in a concurrent
+	 * environment. The consumer should accept subsequent events and close/clean
+	 * up when the Close or Error event is received.
+	 * 
+	 * Though ABORT has the value -1, any value less than 0 will act as an
+	 * abort.
+	 */
+	long	ABORT		= -1;
+
+	/**
+	 * A 0 indicates that the consumer is willing to receive subsequent events
+	 * at full speeds.
+	 * 
+	 * Any value more than 0 will indicate that the consumer is becoming
+	 * overloaded and wants a delay of the given milliseconds before the next
+	 * event is sent. This allows the consumer to pushback the event delivery
+	 * speed.
+	 */
+	long	CONTINUE	= 0;
+
+	/**
+	 * Accept an event from a source. Events can be delivered on multiple
+	 * threads simultaneously. However, Close and Error events are the last
+	 * events received, no more events must be sent after them.
+	 * 
+	 * @param event The event
+	 * @return less than 0 means abort, 0 means continue, more than 0 means
+	 *         delay ms
+	 * @throws Exception to indicate that an error has occured and that no
+	 *         further events should be delivered to this
+	 *         {@link PushEventConsumer}
+	 */
+	long accept(PushEvent<? extends T> event) throws Exception;
+
+}