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Diffstat (limited to 'common-app-api/src/main/java/org/openecomp/sdc/common/datastructure/FunctionalInterfaces.java')
| -rw-r--r-- | common-app-api/src/main/java/org/openecomp/sdc/common/datastructure/FunctionalInterfaces.java | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/common-app-api/src/main/java/org/openecomp/sdc/common/datastructure/FunctionalInterfaces.java b/common-app-api/src/main/java/org/openecomp/sdc/common/datastructure/FunctionalInterfaces.java new file mode 100644 index 0000000000..12ba17baa5 --- /dev/null +++ b/common-app-api/src/main/java/org/openecomp/sdc/common/datastructure/FunctionalInterfaces.java @@ -0,0 +1,282 @@ +/*- + * ============LICENSE_START======================================================= + * SDC + * ================================================================================ + * Copyright (C) 2017 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.openecomp.sdc.common.datastructure; + +import java.util.function.Function; +import java.util.function.Supplier; + +/** + * Class For Functional interfaces And Functional Methods + * + * @author mshitrit + * + */ +public class FunctionalInterfaces { + private static final int DEFAULT_REDO_INTERVAL_TIME_MS = 50; + private static final int DEFAULT_MAX_WAIT_TIME_MS = 10000; + + /** + * @author mshitrit Consumer that takes two parameters + */ + public interface ConsumerTwoParam<T1, T2> { + /** + * Same Accept method, but takes two parameters + * + * @param t1 + * @param t2 + */ + void accept(T1 t1, T2 t2); + } + + /** + * @author mshitrit Function that takes two parameters + */ + public interface FunctionTwoParam<T1, T2, R> { + /** + * Same apply method, but takes two parameters + * + * @param t1 + * @param t2 + * @return + */ + R apply(T1 t1, T2 t2); + } + + /** + * @author mshitrit Function that throws an exception + */ + public interface FunctionThrows<T, R, E extends Exception> { + /** + * Same apply method, but throws an exception + * + * @param t + * @return + */ + R apply(T t) throws E; + } + + /** + * @author mshitrit Supplier that throws an exception + */ + public interface SupplierThrows<R, E extends Exception> { + /** + * Same get method, but throws an exception + * + * @return + * @throws E + */ + R get() throws E; + } + + /** + * @author mshitrit Consumer that throws an exception + */ + public interface ConsumerThrows<T, E extends Exception> { + /** + * Same accept, but throws an exception + * + * @param t + * @throws E + */ + void accept(T t) throws E; + } + + /** + * @author mshitrit Runnable that throws an exception + */ + public interface RunnableThrows<E extends Exception> { + /** + * Same run, but throws an exception + * + * @throws E + */ + void run() throws E; + } + + /** + * Runs a method that declares throwing an Exception and has a return value. + * <br> + * In case Exception Occurred replaces it with FunctionalAttException. <br> + * This is useful for two cases:<br> + * 1.using methods that throws exceptions in streams.<br> + * 2.replacing declared exception with undeclared exception (Runtime).<br> + * See below Use Case:<br> + * Instead of: intList.stream().map(e -> fooThrowsAndReturnsBoolean(e)); - + * does not compile !<br> + * Use This : intList.stream().map(e -> swallowException( () -> + * fooThrowsAndReturnsBoolean(e))); - compiles !<br> + * + * @param methodToRun + * @return + */ + public static <R, E extends Exception> R swallowException(SupplierThrows<R, E> methodToRun) { + try { + final R result = methodToRun.get(); + return result; + } catch (Exception e) { + throw new FunctionalAttException(e); + } + } + + /** + * Runs a method that declares throwing an Exception without return value. + * <br> + * In case Exception Occurred replaces it with FunctionalAttException. <br> + * This is useful for two cases:<br> + * 1.using methods that throws exceptions in streams.<br> + * 2.replacing declared exception with undeclared exception (Runtime).<br> + * See below Use Case:<br> + * + * @param methodToRun + */ + public static <E extends Exception> void swallowException(RunnableThrows<E> methodToRun) { + + SupplierThrows<Boolean, E> runnableWrapper = () -> { + methodToRun.run(); + return true; + }; + swallowException(runnableWrapper); + } + + private static class FunctionalAttException extends RuntimeException { + private static final long serialVersionUID = 1L; + + private FunctionalAttException(Exception e) { + super(e); + } + } + + /** + * Runs the given method.<br> + * Verify the method result against the resultVerifier.<br> + * If verification passed returns the result.<br> + * If Verification failed keeps retrying until it passes or until 10 seconds + * pass.<br> + * If Exception Occurred keeps retrying until it passes or until 10 seconds + * pass,<br> + * If last retry result caused an exception - it is thrown. + * + * @param methodToRun + * given Method + * @param resultVerifier + * verifier for the method result + * @return + */ + public static <R> R retryMethodOnResult(Supplier<R> methodToRun, Function<R, Boolean> resultVerifier) { + return retryMethodOnResult(methodToRun, resultVerifier, DEFAULT_MAX_WAIT_TIME_MS, + DEFAULT_REDO_INTERVAL_TIME_MS); + } + + /** + * Runs the given method.<br> + * Verify the method result against the resultVerifier.<br> + * If verification passed returns the result.<br> + * If Verification failed keeps retrying until it passes or until maxWait + * pass.<br> + * If Exception Occurred keeps retrying until it passes or until maxWait + * pass,<br> + * If last retry result caused an exception - it is thrown. + * + * @param methodToRun + * given Method + * @param resultVerifier + * verifier for the method result + * @param maxWaitMS + * @param retryIntervalMS + * @return + */ + public static <R> R retryMethodOnResult(Supplier<R> methodToRun, Function<R, Boolean> resultVerifier, + long maxWaitMS, long retryIntervalMS) { + boolean stopSearch = false; + R ret = null; + int timeElapsed = 0; + FunctionalAttException functionalExceotion = null; + boolean isExceptionInLastTry = false; + while (!stopSearch) { + try { + ret = methodToRun.get(); + stopSearch = resultVerifier.apply(ret); + isExceptionInLastTry = false; + } catch (Exception e) { + functionalExceotion = new FunctionalAttException(e); + isExceptionInLastTry = true; + + } finally { + sleep(retryIntervalMS); + timeElapsed += retryIntervalMS; + if (timeElapsed > maxWaitMS) { + stopSearch = true; + } + } + + } + if (isExceptionInLastTry) { + throw functionalExceotion; + } else { + return ret; + } + + } + + /** + * Runs the given method.<br> + * In case exception occurred runs the method again either until succeed or + * until 10 seconds pass. + * + * @param methodToRun + * given method + * @return + */ + + public static <R> R retryMethodOnException(Supplier<R> methodToRun) { + Function<R, Boolean> dummyVerifier = someResult -> true; + return retryMethodOnResult(methodToRun, dummyVerifier, DEFAULT_MAX_WAIT_TIME_MS, DEFAULT_REDO_INTERVAL_TIME_MS); + } + + /** + * Runs the given method.<br> + * In case exception occurred runs the method again either until succeed or + * until 10 seconds pass. + * + * @param methodToRun + * given method + */ + public static void retryMethodOnException(Runnable methodToRun) { + Function<Boolean, Boolean> dummyVerifier = someResult -> true; + Supplier<Boolean> dummySupplier = () -> { + methodToRun.run(); + return true; + }; + retryMethodOnResult(dummySupplier, dummyVerifier, DEFAULT_MAX_WAIT_TIME_MS, DEFAULT_REDO_INTERVAL_TIME_MS); + } + + /** + * Same as Thread.sleep but throws a FunctionalAttException + * (RuntimeException) instead of InterruptedException.<br> + * + * @param millis + */ + public static void sleep(long millis) { + swallowException(() -> Thread.sleep(millis)); + + } + +} |