1 files changed, 65 insertions, 0 deletions
diff --git a/framework/src/onos/core/net/src/main/java/org/onosproject/core/impl/BlockAllocatorBasedIdGenerator.java b/framework/src/onos/core/net/src/main/java/org/onosproject/core/impl/BlockAllocatorBasedIdGenerator.java
new file mode 100644
index 00000000..267cd713
--- /dev/null
+++ b/framework/src/onos/core/net/src/main/java/org/onosproject/core/impl/BlockAllocatorBasedIdGenerator.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * 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.onosproject.core.impl;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.onosproject.core.IdBlock;
+import org.onosproject.core.IdGenerator;
+import org.onosproject.core.UnavailableIdException;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Base class of {@link IdGenerator} implementations which use {@link IdBlockAllocator} as
+ * backend.
+ */
+public class BlockAllocatorBasedIdGenerator implements IdGenerator {
+    protected final IdBlockAllocator allocator;
+    protected IdBlock idBlock;
+    protected AtomicBoolean initialized;
+
+
+    /**
+     * Constructs an ID generator which use {@link IdBlockAllocator} as backend.
+     *
+     * @param allocator the ID block allocator to use
+     */
+    protected BlockAllocatorBasedIdGenerator(IdBlockAllocator allocator) {
+        this.allocator = checkNotNull(allocator, "allocator cannot be null");
+        this.initialized = new AtomicBoolean(false);
+    }
+
+    @Override
+    public long getNewId() {
+        try {
+            if (!initialized.get()) {
+                synchronized (allocator) {
+                    if (!initialized.get()) {
+                        idBlock = allocator.allocateUniqueIdBlock();
+                        initialized.set(true);
+                    }
+                }
+            }
+            return idBlock.getNextId();
+        } catch (UnavailableIdException e) {
+            synchronized (allocator) {
+                idBlock = allocator.allocateUniqueIdBlock();
+            }
+            return idBlock.getNextId();
+        }
+    }
+}