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Diffstat (limited to 'core/core-engine/src/main/java/org/onap/policy/apex/core/engine/executor/Executor.java')
| -rw-r--r-- | core/core-engine/src/main/java/org/onap/policy/apex/core/engine/executor/Executor.java | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/executor/Executor.java b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/executor/Executor.java new file mode 100644 index 000000000..d659002b2 --- /dev/null +++ b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/executor/Executor.java @@ -0,0 +1,161 @@ +/*- + * ============LICENSE_START======================================================= + * Copyright (C) 2016-2018 Ericsson. 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. + * + * SPDX-License-Identifier: Apache-2.0 + * ============LICENSE_END========================================================= + */ + +package org.onap.policy.apex.core.engine.executor; + +import org.onap.policy.apex.context.ContextException; +import org.onap.policy.apex.core.engine.ExecutorParameters; +import org.onap.policy.apex.core.engine.executor.exception.StateMachineException; +import org.onap.policy.apex.model.basicmodel.concepts.AxConcept; + +/** + * This interface defines what operations must be provided by an executing entity in Apex. It is implemented by classes + * that execute logic in a state machine. Each executor has an incoming entity {@code IN} that triggers execution, an + * outgoing entity {@code OUT} that is produced by execution, a subject {@code SUBJECT} that is being executed, and a + * context {@code CONTEXT} in which execution is being carried out. An executor can be part of a chain of executors and + * the {@code setNext} method is used to set the next executor to be executed after this executor has completed. + * + * @author Sven van der Meer (sven.van.der.meer@ericsson.com) + * @author Liam Fallon (liam.fallon@ericsson.com) + * + * @param <IN> type of the incoming entity + * @param <OUT> type of the outgoing entity + * @param <SUBJECT> type that is the subject of execution + * @param <CONTEXT> context holding the context of execution + */ + +public interface Executor<IN, OUT, SUBJECT, CONTEXT> { + /** + * Save the subject and context of the executor. + * + * @param parent the parent executor of this executor or null if this executor is the top executor + * @param executorSubject the executor subject, the subject of execution + * @param executorContext the executor context, the context in which execution takes place + */ + void setContext(Executor<?, ?, ?, ?> parent, SUBJECT executorSubject, CONTEXT executorContext); + + /** + * Prepares the processing. + * + * @throws StateMachineException thrown when a state machine execution error occurs + */ + void prepare() throws StateMachineException; + + /** + * Executes the executor, running through its context in its natural order. + * + * @param executionID the execution ID of the current APEX execution policy thread + * @param incomingEntity the incoming entity that triggers execution + * @return The outgoing entity that is the result of execution + * @throws StateMachineException on an execution error + * @throws ContextException on context errors + */ + OUT execute(long executionID, IN incomingEntity) throws StateMachineException, ContextException; + + /** + * Carry out the preparatory work for execution. + * + * @param executionID the execution ID of the current APEX execution policy thread + * @param incomingEntity the incoming entity that triggers execution + * @throws StateMachineException on an execution error + * @throws ContextException on context errors + */ + void executePre(long executionID, IN incomingEntity) throws StateMachineException, ContextException; + + /** + * Carry out the post work for execution, the returning entity should be set by the child execution object. + * + * @param returnValue the return value indicates whether the execution was successful and, if it failed, how it + * failed + * @throws StateMachineException on an execution error + * @throws ContextException On context errors + */ + void executePost(boolean returnValue) throws StateMachineException, ContextException; + + /** + * Cleans up after processing. + * + * @throws StateMachineException thrown when a state machine execution error occurs + */ + void cleanUp() throws StateMachineException; + + /** + * Get the key associated with the executor. + * + * @return The key associated with the executor + */ + AxConcept getKey(); + + /** + * Get the parent executor of the executor. + * + * @return The parent executor of this executor + */ + Executor<?, ?, ?, ?> getParent(); + + /** + * Get the subject of the executor. + * + * @return The subject for the executor + */ + SUBJECT getSubject(); + + /** + * Get the context of the executor. + * + * @return The context for the executor + */ + CONTEXT getContext(); + + /** + * Get the incoming object of the executor. + * + * @return The incoming object for the executor + */ + IN getIncoming(); + + /** + * Get the outgoing object of the executor. + * + * @return The outgoing object for the executor + */ + OUT getOutgoing(); + + /** + * Save the next executor for this executor. + * + * @param nextExecutor the next executor + */ + void setNext(Executor<IN, OUT, SUBJECT, CONTEXT> nextExecutor); + + /** + * Get the next executor to be run after this executor completes its execution. + * + * @return The next executor + */ + Executor<IN, OUT, SUBJECT, CONTEXT> getNext(); + + /** + * Set parameters for this executor, overloaded by executors that use parameters. + * + * @param parameters executor parameters + */ + void setParameters(ExecutorParameters parameters); +} |