Java tutorial
package com.thinkbiganalytics.nifi.rest.client; /*- * #%L * thinkbig-nifi-rest-client-api * %% * Copyright (C) 2017 ThinkBig Analytics * %% * 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. * #L% */ import org.apache.commons.lang3.exception.ExceptionUtils; import org.apache.http.NoHttpResponseException; import org.apache.http.conn.HttpHostConnectException; import java.net.ConnectException; import javax.ws.rs.NotFoundException; import javax.ws.rs.ProcessingException; /** */ public class NifiRestClientExceptionTranslator { public static Throwable translateException(Throwable e) { //Return if its already translated to a NifiClientRuntimeException if (e instanceof NifiClientRuntimeException) { return e; } if (e instanceof NotFoundException) { return new NifiComponentNotFoundException(e.getMessage()); } else if (e instanceof NullPointerException) { return new NifiConnectionException("Verify NiFi is running and try again", e); } else if (e instanceof ProcessingException) { int throwables = ExceptionUtils.getThrowableCount(e); if (throwables > 1) { Throwable rootCause = ExceptionUtils.getRootCause(e); if (rootCause instanceof NoHttpResponseException || rootCause instanceof HttpHostConnectException || rootCause instanceof ConnectException) { //connection error return new NifiConnectionException(e.getMessage(), e); } } } return new NifiClientRuntimeException(e); } }