2 * ============LICENSE_START=======================================================
3 * Copyright (C) 2016-2018 Ericsson. All rights reserved.
4 * ================================================================================
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
17 * SPDX-License-Identifier: Apache-2.0
18 * ============LICENSE_END=========================================================
21 package org.onap.policy.apex.core.engine.engine.impl;
23 import java.util.HashMap;
24 import org.onap.policy.apex.core.engine.context.ApexInternalContext;
25 import org.onap.policy.apex.core.engine.event.EnEvent;
26 import org.onap.policy.apex.core.engine.executor.ExecutorFactory;
27 import org.onap.policy.apex.core.engine.executor.StateMachineExecutor;
28 import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
29 import org.onap.policy.apex.core.engine.executor.impl.ExecutorFactoryImpl;
30 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
31 import org.onap.policy.apex.model.basicmodel.service.ModelService;
32 import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
33 import org.onap.policy.apex.model.eventmodel.concepts.AxEvents;
34 import org.onap.policy.apex.model.policymodel.concepts.AxPolicies;
35 import org.onap.policy.apex.model.policymodel.concepts.AxPolicy;
36 import org.slf4j.ext.XLogger;
37 import org.slf4j.ext.XLoggerFactory;
40 * This handler holds and manages state machines for each policy in an Apex engine. When the class is instantiated, an
41 * executor {@link StateMachineExecutor} is created for each policy in the policy model the state machine handler will
42 * execute. The executors for each policy are held in a map indexed by event.
44 * <p>When an event is received on the policy, the state machine executor to execute that event is looked up on the
45 * executor map and the event is passed to the executor for execution.
50 public class StateMachineHandler {
51 // Logger for this class
52 private static final XLogger LOGGER = XLoggerFactory.getXLogger(StateMachineHandler.class);
54 // The key of the Apex model we are executing
55 private final AxArtifactKey key;
57 // The state machines in this engine
58 private final HashMap<AxEvent, StateMachineExecutor> stateMachineExecutorMap = new HashMap<>();
60 // The executor factory is used to get logic executors for the particular type of executor we
62 // selection logic or task logic
63 private final ExecutorFactory executorFactory;
66 * This constructor builds the state machines for the policies in the apex model.
68 * @param internalContext The internal context we are using
69 * @throws StateMachineException On state machine initiation errors
71 protected StateMachineHandler(final ApexInternalContext internalContext) throws StateMachineException {
72 LOGGER.entry("StateMachineHandler()->" + internalContext.getKey().getId());
74 key = internalContext.getKey();
76 // Create the executor factory to generate executors as the engine runs policies
77 executorFactory = new ExecutorFactoryImpl();
79 // Iterate over the policies in the policy model and create a state machine for each one
80 for (final AxPolicy policy : ModelService.getModel(AxPolicies.class).getPolicyMap().values()) {
81 // Create a state machine for this policy
82 final StateMachineExecutor thisStateMachineExecutor =
83 new StateMachineExecutor(executorFactory, policy.getKey());
85 // This executor is the top executor so has no parent
86 thisStateMachineExecutor.setContext(null, policy, internalContext);
88 // Get the incoming trigger event
89 final AxEvent triggerEvent = ModelService.getModel(AxEvents.class)
90 .get(policy.getStateMap().get(policy.getFirstState()).getTrigger());
92 // Put the state machine executor on the map for this trigger
93 final StateMachineExecutor lastStateMachineExecutor =
94 stateMachineExecutorMap.put(triggerEvent, thisStateMachineExecutor);
95 if (lastStateMachineExecutor != null
96 && lastStateMachineExecutor.getSubject() != thisStateMachineExecutor.getSubject()) {
97 LOGGER.error("No more than one policy in a model can have the same trigger event. In model "
98 + internalContext.getKey().getId() + " Policy ("
99 + lastStateMachineExecutor.getSubject().getKey().getId() + ") and Policy ("
100 + thisStateMachineExecutor.getSubject().getKey().getId() + ") have the same Trigger event ("
101 + triggerEvent.getKey().getId() + ") ");
102 LOGGER.error(" Policy (" + lastStateMachineExecutor.getSubject().getKey() + ") has overwritten Policy ("
103 + thisStateMachineExecutor.getSubject().getKey().getId()
104 + " so this overwritten policy will never be triggered in this engine.");
108 LOGGER.exit("StateMachineHandler()<-" + internalContext.getKey().getId());
112 * This constructor starts the state machines for each policy, carrying out whatever initialization executors need.
114 * @throws StateMachineException On state machine initiation errors
116 protected void start() throws StateMachineException {
117 LOGGER.entry("start()->" + key.getId());
119 // Iterate over the state machines
120 for (final StateMachineExecutor smExecutor : stateMachineExecutorMap.values()) {
122 smExecutor.prepare();
123 } catch (final StateMachineException e) {
124 final String stateMachineId = smExecutor.getContext().getKey().getId();
125 String message = "start()<-" + key.getId() + ", start failed, state machine \"" + stateMachineId + "\"";
126 LOGGER.warn(message, e);
127 throw new StateMachineException(message, e);
131 LOGGER.exit("start()<-" + key.getId());
135 * This method is called to execute an event on the state machines in an engine.
137 * @param event The trigger event for the state machine
138 * @return The result of the state machine execution run
139 * @throws StateMachineException On execution errors in a state machine
141 protected EnEvent execute(final EnEvent event) throws StateMachineException {
142 LOGGER.entry("execute()->" + event.getName());
144 // Try to execute the state machine for the trigger
145 final StateMachineExecutor stateMachineExecutor = stateMachineExecutorMap.get(event.getAxEvent());
146 if (stateMachineExecutor == null) {
147 final String exceptionMessage =
148 "state machine execution not possible, policy not found for trigger event " + event.getName();
149 LOGGER.warn(exceptionMessage);
151 event.setExceptionMessage(exceptionMessage);
155 // Run the state machine
157 LOGGER.debug("execute(): state machine \"{}\" execution starting . . .", stateMachineExecutor);
158 final EnEvent outputObject =
159 stateMachineExecutor.execute(event.getExecutionId(), event.getExecutionProperties(), event);
161 LOGGER.debug("execute()<-: state machine \"{}\" execution completed", stateMachineExecutor);
163 } catch (final Exception e) {
164 LOGGER.warn("execute()<-: state machine \"" + stateMachineExecutor + "\" execution failed", e);
165 throw new StateMachineException("execute()<-: execution failed on state machine " + stateMachineExecutor,
171 * Closes down the state machines of an engine.
173 protected void stop() {
174 LOGGER.entry("stop()->");
176 // Iterate through all state machines and clean them
177 for (final StateMachineExecutor smExecutor : stateMachineExecutorMap.values()) {
179 smExecutor.cleanUp();
180 } catch (final StateMachineException e) {
181 final String smId = smExecutor.getContext().getKey().getId();
182 LOGGER.warn("stop()<-clean up failed, state machine \"" + smId + "\" cleanup failed", e);
185 LOGGER.exit("stop()<-");