Merge "Add Network Logging Feature"

6 files changed, 363 insertions, 71 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapper.java b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedService.java
index 6f800015..c5050c83 100644
--- a/utils/src/main/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapper.java
+++ b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedService.java
@@ -1,9 +1,8 @@
 /*
  * ============LICENSE_START=======================================================
- * ONAP Policy Engine - Common Modules
+ * utils
  * ================================================================================
- * Copyright (C) 2019 Samsung Electronics. All rights reserved.
- * Modifications Copyright (C) 2019 AT&T Intellectual Property.
+ * Copyright (C) 2019 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.
@@ -19,29 +18,30 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.policy.common.utils.slf4j;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+package org.onap.policy.common.utils.services;
 
 /**
- * Helper class to retrieve particular types of loggers without storing the logger name everywhere in ths code.
+ * This is a base interface that is used to control the order of a list
+ * of services (features) discovered via 'ServiceLoader'. See
+ * 'OrderedServiceImpl' for more details.
  */
-public class LoggerFactoryWrapper {
-
+@FunctionalInterface
+public interface OrderedService {
     /**
-     * Constructs the object.
+     * Get sequence number.
+     *
+     * @return an integer sequence number, which determines the order of a list
+     *     of objects implementing this interface
      */
-    private LoggerFactoryWrapper() {
-        super();
-    }
+    public int getSequenceNumber();
+
 
     /**
-     * Get Network Logger.
+     * Get the name.
      *
-     * @return logger instance
+     * @return the name of the ordered service
      */
-    public static Logger getNetworkLogger() {
-        return LoggerFactory.getLogger("network");
+    public default String getName() {
+        return this.getClass().getName();
     }
 }
diff --git a/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java
new file mode 100644
index 00000000..bbd30220
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java
@@ -0,0 +1,135 @@
+/*
+ * ============LICENSE_START=======================================================
+ * utils
+ * ================================================================================
+ * Copyright (C) 2019 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.common.utils.services;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.ServiceLoader;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class is a template for building a sorted list of service instances,
+ * which are discovered and created using 'ServiceLoader'. 
+ */
+public class OrderedServiceImpl<T extends OrderedService> {
+    // logger
+    private static Logger  logger = LoggerFactory.getLogger(OrderedServiceImpl.class); 
+
+    // sorted list of instances implementing the service
+    private List<T> implementers = null;
+
+    // 'ServiceLoader' that is used to discover and create the services
+    private ServiceLoader<T> serviceLoader = null;
+
+    // use this to ensure that we only use one unique instance of each class
+    @SuppressWarnings("rawtypes")
+    private static HashMap<Class,OrderedService> classToSingleton = new HashMap<>();
+
+    /**
+     * Constructor - create the 'ServiceLoader' instance.
+     *
+     * @param clazz the class object associated with 'T' (I supposed it could
+     *     be a subclass, but I'm not sure this is useful)
+     */
+    public OrderedServiceImpl(Class<T> clazz) {
+        // This constructor wouldn't be needed if 'T.class' was legal
+        serviceLoader = ServiceLoader.load(clazz);
+    }
+
+    /**
+     * Get List of implementers.
+     * 
+     * @return the sorted list of services implementing interface 'T' discovered
+     *     by 'ServiceLoader'.
+     */
+    public synchronized List<T> getList() {
+        if (implementers == null) {
+            rebuildList();
+        }
+        return implementers;
+    }
+
+    /**
+     * This method is called by 'getList', but could also be called directly if
+     * we were running with a 'ClassLoader' that supported the dynamic addition
+     * of JAR files. In this case, it could be invoked in order to discover any
+     * new services implementing interface 'T'. This is probably a relatively
+     * expensive operation in terms of CPU and elapsed time, so it is best if it
+     * isn't invoked too frequently.
+     *
+     * @return the sorted list of services implementing interface 'T' discovered
+     *      by 'ServiceLoader'.
+     */
+    @SuppressWarnings("unchecked")
+    public synchronized List<T> rebuildList() {
+        // build a list of all of the current implementors
+        List<T> tmp = new LinkedList<>();
+        for (T service : serviceLoader) {
+            tmp.add((T)getSingleton(service));
+        }
+
+        // Sort the list according to sequence number, and then alphabetically
+        // according to full class name.
+        Collections.sort(tmp, (o1, o2) -> {
+            int s1 = o1.getSequenceNumber();
+            int s2 = o2.getSequenceNumber();
+            if (s1 < s2) {
+                return -1;
+            } else if (s1 > s2) {
+                return 1;
+            } else {
+                return o1.getClass().getName().compareTo(o2.getClass().getName());
+            }
+        });
+
+        // create an unmodifiable version of this list
+        implementers = Collections.unmodifiableList(tmp);
+        logger.info("***** OrderedServiceImpl implementers:\n {}", implementers);
+        return implementers;
+    }
+
+    /**
+     * If a service implements multiple APIs managed by 'ServiceLoader', a
+     * separate instance is created for each API. This method ensures that
+     * the first instance is used in all of the lists.
+     *
+     * @param service this is the object created by ServiceLoader
+     * @return the object to use in place of 'service'. If 'service' is the first
+     *     object of this class created by ServiceLoader, it is returned. If not,
+     *     the object of this class that was initially created is returned
+     *     instead.
+     */
+    private static synchronized OrderedService getSingleton(OrderedService service) {
+        // see if we already have an instance of this class
+        OrderedService rval = classToSingleton.get(service.getClass());
+        if (rval == null) {
+            // No previous instance of this class exists -- use the supplied
+            // instance, and place it in the table.
+            rval = service;
+            classToSingleton.put(service.getClass(), service);
+        }
+        return rval;
+    }
+}
diff --git a/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java b/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
index eb918d35..e5a79bc3 100644
--- a/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
+++ b/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
@@ -250,7 +250,9 @@ public class ResourceUtilsTest {
         assertNull(theString);
 
         theString = ResourceUtils.getResourceAsString("");
-        assertEquals("logback-test.xml\norg\ntestdir\n", theString);
+
+        assertEquals("logback-test.xml\nMETA-INF\norg\ntestdir\n", theString);
+
     }
 
     @Test
diff --git a/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java b/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java
new file mode 100644
index 00000000..39c8a2be
--- /dev/null
+++ b/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java
@@ -0,0 +1,205 @@
+/*
+ * ============LICENSE_START=======================================================
+ * utils
+ * ================================================================================
+ * Copyright (C) 2019 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.common.utils.services;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class OrderedServiceImplTest {
+
+    private static final int HIGH_PRIORITY_NUM = -1000;
+    private static final int LOW_PRIORITY_NUM = 1000;
+
+    private static GenericService highPrioService;
+    private static GenericService lowPrioService;
+
+    /**
+     * Saves the original state of the ordered service list to restore after each test.
+     */
+    @BeforeClass
+    public static void setup() {
+        List<GenericService> implementers = GenericService.providers.getList();
+        highPrioService = implementers.get(0);
+        lowPrioService = implementers.get(1);
+    }
+
+    /**
+     * Restores original state after each test.
+     */
+    @Before
+    public void resetOrder() {
+        highPrioService.setSequenceNumber(HIGH_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+    }
+
+    /**
+     * Tests obtaining a list of service implementers.
+     */
+    @Test
+    public void getListTest() {
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+    }
+
+    /**
+     * Tests inverting the priority of two services to ensure the list is rebuilt
+     * with the new order.
+     */
+    @Test
+    public void rebuildListInvertedPriorityTest() {
+
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        highPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(HIGH_PRIORITY_NUM);
+
+        implementers = GenericService.providers.rebuildList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(lowPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        assertEquals(highPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+    }
+
+    /**
+     * Tests that the service list is ordered alphabetically by class names
+     * if the priorities are equivalent.
+     */
+    @Test
+    public void rebuildListEqualPriorityTest() {
+
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        highPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+
+        implementers = GenericService.providers.rebuildList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(LOW_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+    }
+
+    /**
+     * Test interface that extends OrderedService to allow changing the sequence number.
+     */
+    public static interface GenericService extends OrderedService {
+
+        /**
+         * Providers of the GenericService interface.
+         */
+        OrderedServiceImpl<GenericService> providers = new OrderedServiceImpl<>(GenericService.class);
+
+        /**
+         * Sets the sequence number of the service.
+         */
+        public void setSequenceNumber(int seqNum);
+
+    }
+
+    /**
+     * A high priority service class.
+     */
+    public static class HighPriorityService implements GenericService {
+
+        /**
+         * Defaults to a high priority.
+         */
+        private int seqNum = HIGH_PRIORITY_NUM;
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public int getSequenceNumber() {
+            return this.seqNum;
+        }
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public void setSequenceNumber(int seqNum) {
+            this.seqNum = seqNum;
+        }
+
+    }
+
+    /**
+     * A low priority service class.
+     */
+    public static class LowPriorityService implements GenericService {
+
+        /**
+         * Defaults to a low priority.
+         */
+        private int seqNum = LOW_PRIORITY_NUM;
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public int getSequenceNumber() {
+            return this.seqNum;
+        }
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public void setSequenceNumber(int seqNum) {
+            this.seqNum = seqNum;
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java b/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java
deleted file mode 100644
index 4bf8db30..00000000
--- a/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * ============LICENSE_START=======================================================
- * ONAP Policy Engine - Common Modules
- * ================================================================================
- * Copyright (C) 2019 Samsung Electronics. All rights reserved.
- * Modifications Copyright (C) 2019 AT&T Intellectual Property.
- * ================================================================================
- * 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.common.utils.slf4j;
-
-import static org.junit.Assert.assertSame;
-import static org.mockito.Mockito.mock;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import org.powermock.api.mockito.PowerMockito;
-import org.powermock.core.classloader.annotations.PrepareForTest;
-import org.powermock.modules.junit4.PowerMockRunner;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-
-@RunWith(PowerMockRunner.class)
-@PrepareForTest(LoggerFactory.class)
-public class LoggerFactoryWrapperTest {
-    @Test
-    public void test_get_network_logger() {
-        String netLoggerName = "network";
-        Logger mockLogger = mock(Logger.class);
-
-        PowerMockito.mockStatic(LoggerFactory.class);
-
-        PowerMockito.when(LoggerFactory.getLogger(netLoggerName)).thenReturn(mockLogger);
-        assertSame(mockLogger, LoggerFactoryWrapper.getNetworkLogger());
-    }
-}
diff --git a/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService b/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService
new file mode 100644
index 00000000..1e920f46
--- /dev/null
+++ b/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService
@@ -0,0 +1,2 @@
+org.onap.policy.common.utils.services.OrderedServiceImplTest$HighPriorityService
+org.onap.policy.common.utils.services.OrderedServiceImplTest$LowPriorityService
\ No newline at end of file