Merge "Add m2 model, including the LCM application"

2 files changed, 172 insertions, 0 deletions

diff --git a/controlloop/m2/util/src/main/java/org/onap/policy/util/DroolsSessionCommonSerializable.java b/controlloop/m2/util/src/main/java/org/onap/policy/util/DroolsSessionCommonSerializable.java
new file mode 100644
index 000000000..d8501fea8
--- /dev/null
+++ b/controlloop/m2/util/src/main/java/org/onap/policy/util/DroolsSessionCommonSerializable.java
@@ -0,0 +1,136 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * util
+ * ================================================================================
+ * Copyright (C) 2020 AT&T 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.policy.util;
+
+import java.io.InvalidObjectException;
+import java.io.ObjectStreamException;
+import java.io.Serializable;
+import java.util.HashMap;
+
+import org.onap.policy.drools.core.PolicySession;
+
+/**
+ * This class provides a way to serialize/deserialize objects by locating
+ * an already existing object on the remote end, and using that instead. It
+ * is useful for objects that may be shared by multiple transactions.
+ */
+public class DroolsSessionCommonSerializable implements Serializable {
+    private static final long serialVersionUID = 1L;
+
+    // identifies an object within a Drools session
+    private String name;
+
+    // the object is serialized, but is only used if the corresponding object
+    // on the remote end can't be located for some reason
+    private Object object;
+
+    /**
+     * Constructor - initialize instance, and also store a reference to
+     * the object in a 'PolicySession' adjunct.
+     *
+     * @param name identifies the object within the Drools session
+     * @param object the shared object
+     */
+    public DroolsSessionCommonSerializable(String name, Object object) {
+        this.name = name;
+        this.object = object;
+
+        // store a reference to the object within the adjunct
+        // (only works if we can locate the Drools session)
+        Adjunct adjunct = getAdjunct();
+        if (adjunct != null) {
+            adjunct.put(name, object);
+        }
+    }
+
+    /**
+     * Return this object as a String.
+     *
+     * {@inheritDoc}
+     */
+    @Override
+    public String toString() {
+        return "DroolsSessionCommonSerializable[" + name + "]";
+    }
+
+    /**
+     * This method runs as part of deserialization. If we are able to locate
+     * the 'PolicySession' and adjunct, and fetch the replacement object from
+     * the adjunct, that is used. Otherwise, the deserialized object is used
+     * (which is likely a duplicate).
+     *
+     * @return the local named object (if available), or the deserialized
+     *     object
+     */
+    private Object readResolve() throws ObjectStreamException {
+        Adjunct adjunct = getAdjunct();
+        Object replacementObject;
+
+        if (adjunct != null && (replacementObject = adjunct.get(name)) != null) {
+            // we found the adjunct, as well as the replacement object -- use
+            // the replacement object
+            return replacementObject;
+        }
+
+        // either we couldn't find the adjunct, or couldn't locate the object
+        // within the adjunct
+        return object;
+    }
+
+    /**
+     * This method will:
+     * 1) Locate the 'PolicySession' (only works from within the Drools thread),
+     * 2) Find or create the adjunct.
+     *
+     * @return the adjunct, or 'null' if we aren't running within a
+     *     Drools session
+     */
+    private Adjunct getAdjunct() {
+        // PolicySession - this only works from within the Drools thread
+        PolicySession session = PolicySession.getCurrentSession();
+        Adjunct adjunct = null;
+        if (session != null) {
+            // we found the 'PolicySession' -- now, look for the adjunct
+            Object adj = session.getAdjunct(Adjunct.class);
+            if (adj == null || !(adj instanceof Adjunct)) {
+                // adjunct does not exist, or has the wrong type -- create it
+                adjunct = new Adjunct();
+                session.setAdjunct(Adjunct.class, adjunct);
+            } else {
+                // found the adjunct -- return it
+                adjunct = (Adjunct)adj;
+                //adjunct = Adjunct.class.cast(adj);
+            }
+        }
+        return adjunct;
+    }
+
+    /* ============================================================ */
+
+    /**
+     * While 'HashMap<String, Object>' could be used directly instead of defining
+     * a subclass, you can't do run-time type checking of a parameterized type.
+     * As a result, the 'getAdjunct' method (above) would get compile-time
+     * warnings.
+     */
+    private static class Adjunct extends HashMap<String, Object> {
+    }
+}
diff --git a/controlloop/m2/util/src/test/java/org/onap/policy/util/DroolsSessionCommonSerializableTest.java b/controlloop/m2/util/src/test/java/org/onap/policy/util/DroolsSessionCommonSerializableTest.java
new file mode 100644
index 000000000..520158b8c
--- /dev/null
+++ b/controlloop/m2/util/src/test/java/org/onap/policy/util/DroolsSessionCommonSerializableTest.java
@@ -0,0 +1,36 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * util
+ * ================================================================================
+ * Copyright (C) 2020 AT&T 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.policy.util;
+
+import static org.junit.Assert.assertNotNull;
+
+import org.junit.Test;
+
+public class DroolsSessionCommonSerializableTest {
+
+    @Test
+    public void test() {
+        Object object = new Object();
+        DroolsSessionCommonSerializable droolsSessionCommonSerializable =
+            new DroolsSessionCommonSerializable("drools", object);
+        assertNotNull(droolsSessionCommonSerializable.toString());
+    }
+}