migrate sdnr features to phosphorus

[ccsdk/features.git] / sdnr / wt / common / src / main / java / org / onap / ccsdk / features / sdnr / wt / common / threading / KeyBasedThreadpool.java

diff --git a/sdnr/wt/common/src/main/java/org/onap/ccsdk/features/sdnr/wt/common/threading/KeyBasedThreadpool.java b/sdnr/wt/common/src/main/java/org/onap/ccsdk/features/sdnr/wt/common/threading/KeyBasedThreadpool.java
new file mode 100644 (file)
index 0000000..f41a903
--- /dev/null
+++ b/sdnr/wt/common/src/main/java/org/onap/ccsdk/features/sdnr/wt/common/threading/KeyBasedThreadpool.java
@@ -0,0 +1,93 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP : ccsdk features
+ * ================================================================================
+ * Copyright (C) 2020 highstreet technologies GmbH Intellectual Property.
+ * 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.
+ * ============LICENSE_END=========================================================
+ *
+ */
+package org.onap.ccsdk.features.sdnr.wt.common.threading;
+
+import java.util.AbstractMap.SimpleEntry;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map.Entry;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Threadpool for running n instances per key T
+ *
+ * @author jack
+ *
+ * @param <T>
+ * @param <S>
+ */
+public class KeyBasedThreadpool<T, S> implements GenericRunnableFactoryCallback<T> {
+
+    private final Queue<Entry<T, S>> queue;
+    private final List<T> runningKeys;
+    private final int keyPoolSize;
+    private final GenericRunnableFactory<T, S> factory;
+    private final ExecutorService executor;
+
+    /**
+     *
+     * @param poolSize overall maximum amount of threads
+     * @param keyPoolSize amount of threads per key
+     * @param runner runnable to start
+     */
+    public KeyBasedThreadpool(int poolSize, int keyPoolSize, GenericRunnableFactory<T, S> factory) {
+        this.queue = new ConcurrentLinkedQueue<>();
+        this.keyPoolSize = keyPoolSize;
+        this.factory = factory;
+        this.executor = Executors.newFixedThreadPool(poolSize);
+        this.runningKeys = new ArrayList<>();
+    }
+
+    public void execute(T key, S arg) {
+        if (this.isKeyPoolSizeReached(key)) {
+            queue.add(new SimpleEntry<>(key, arg));
+        } else {
+            this.runningKeys.add(key);
+            this.executor.execute(this.factory.create(arg, this));
+        }
+
+    }
+
+    private void executeNext() {
+        Entry<T, S> entry = this.queue.peek();
+        if (!this.isKeyPoolSizeReached(entry.getKey())) {
+            this.queue.poll();
+            this.runningKeys.add(entry.getKey());
+            this.executor.execute(this.factory.create(entry.getValue(), this));
+        }
+    }
+
+    private boolean isKeyPoolSizeReached(T key) {
+        return this.runningKeys.stream().filter(e -> e == key).count() >= this.keyPoolSize;
+    }
+
+    @Override
+    public void onFinish(T key) {
+        this.runningKeys.remove(key);
+        this.executeNext();
+    }
+
+
+}