QPID-529: Priority queue implementation

QPID-2104: LVQ enhancement

These both required some refactoring of the Queue class to allow cleaner implementation of different types of behaviour. The in-memory storage of messages is now abstracted out behind an interface specified by qpid::broker::Messages which qpid::broker::Queue uses. Different implementations of that are available for the standard FIFO queue, priority queues and LVQ (I have also separated out the 'legacy' implementation of LVQ from the new version driven by QPID-2104).



git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1069322 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 61 insertions, 0 deletions

diff --git a/qpid/cpp/src/qpid/broker/Fairshare.h b/qpid/cpp/src/qpid/broker/Fairshare.h
new file mode 100644
index 0000000000..6c4b87f857
--- /dev/null
+++ b/qpid/cpp/src/qpid/broker/Fairshare.h
@@ -0,0 +1,61 @@
+#ifndef QPID_BROKER_FAIRSHARE_H
+#define QPID_BROKER_FAIRSHARE_H
+
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
+#include "qpid/broker/PriorityQueue.h"
+
+namespace qpid {
+namespace framing {
+class FieldTable;
+}
+namespace broker {
+
+/**
+ * Modifies a basic prioirty queue by limiting the number of messages
+ * from each priority level that are dispatched before allowing
+ * dispatch from the next level.
+ */
+class Fairshare : public PriorityQueue
+{
+  public:
+    Fairshare(size_t levels, uint limit);
+    bool getState(uint& priority, uint& count) const;
+    bool setState(uint priority, uint count);
+    void setLimit(size_t level, uint limit);
+    static std::auto_ptr<Messages> create(const qpid::framing::FieldTable& settings);
+    static bool getState(const Messages&, uint& priority, uint& count);
+    static bool setState(Messages&, uint priority, uint count);
+  private:
+    std::vector<uint> limits;
+    
+    uint priority;
+    uint count;
+    
+    uint currentLevel();
+    uint nextLevel();
+    bool isNull();
+    bool limitReached();
+    bool findFrontLevel(uint& p, PriorityLevels&);
+};
+}} // namespace qpid::broker
+
+#endif  /*!QPID_BROKER_FAIRSHARE_H*/