tpalfy commented on a change in pull request #3306: nifi oracle cdc changes using xstream URL: https://github.com/apache/nifi/pull/3306#discussion_r336554086
########## File path: nifi-nar-bundles/nifi-oraclecdc-bundle/nifi-oraclecdc-processors/src/main/java/org/apache/nifi/processors/oraclecdc/controller/impl/StandardOracleClassLoaderService.java ########## @@ -0,0 +1,127 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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. + */ +package org.apache.nifi.processors.oraclecdc.controller.impl; + +import java.net.MalformedURLException; +import java.sql.Driver; +import java.sql.DriverManager; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; + +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.annotation.lifecycle.OnEnabled; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.controller.AbstractControllerService; +import org.apache.nifi.controller.ConfigurationContext; +import org.apache.nifi.expression.AttributeExpression; +import org.apache.nifi.expression.ExpressionLanguageScope; +import org.apache.nifi.processor.util.StandardValidators; +import org.apache.nifi.reporting.InitializationException; +import org.apache.nifi.util.file.classloader.ClassLoaderUtils; +import org.nifi.oraclecdcservice.api.OracleClassLoaderService; + +@Tags({ "dbcp", "jdbc", "database", "connection", "pooling", "store" }) +@CapabilityDescription("Provides a shareable classloader for the Oracle CDC connection pool") + +public class StandardOracleClassLoaderService extends AbstractControllerService implements OracleClassLoaderService { + + public static final PropertyDescriptor DB_DRIVER_LOCATION = new PropertyDescriptor.Builder() + .name("database-driver-locations").displayName("Database Driver Location(s)") + .description( + "Comma-separated list of files/folders and/or URLs containing the driver JAR and its dependencies (if any). For example '/var/tmp/mariadb-java-client-1.1.7.jar'") + .defaultValue(null).required(true) + .addValidator( + StandardValidators.createListValidator(true, true, StandardValidators.createURLorFileValidator())) + .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY).build(); + + private static final List<PropertyDescriptor> properties; + + protected ClassLoader driverClassLoader; + static { + final List<PropertyDescriptor> props = new ArrayList<>(); + props.add(DB_DRIVER_LOCATION); + properties = Collections.unmodifiableList(props); + } + + @Override + protected List<PropertyDescriptor> getSupportedPropertyDescriptors() { + return properties; + } + + @Override + protected PropertyDescriptor getSupportedDynamicPropertyDescriptor(final String propertyDescriptorName) { + return new PropertyDescriptor.Builder().name(propertyDescriptorName).required(false) + .addValidator(StandardValidators + .createAttributeExpressionLanguageValidator(AttributeExpression.ResultType.STRING, true)) + .addValidator(StandardValidators.ATTRIBUTE_KEY_PROPERTY_NAME_VALIDATOR) + .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY).dynamic(true).build(); + } + + /** + * @param context + * the configuration context + * @throws InitializationException + * if unable to create a database connection + */ + @OnEnabled + public void onEnabled(final ConfigurationContext context) throws InitializationException { + final String locationString = context.getProperty(DB_DRIVER_LOCATION).getValue(); + final String drv = "oracle.jdbc.OracleDriver"; + if (locationString != null && locationString.length() > 0) { + try { + // Split and trim the entries + final ClassLoader classLoader = ClassLoaderUtils.getCustomClassLoader(locationString, + this.getClass().getClassLoader(), (dir, name) -> name != null && name.endsWith(".jar")); + + // Workaround which allows to use URLClassLoader for JDBC driver + // loading. + // (Because the DriverManager will refuse to use a driver not + // loaded by the system ClassLoader.) + final Class<?> clazz = Class.forName(drv, true, classLoader); + if (clazz == null) { + throw new InitializationException("Can't load Database Driver " + drv); + } + final Driver driver = (Driver) clazz.newInstance(); + DriverManager.registerDriver(new DriverShim(driver)); + + this.driverClassLoader = classLoader; + } catch (final MalformedURLException e) { + throw new InitializationException("Invalid Database Driver Jar Url", e); + } catch (final Exception e) { + throw new InitializationException("Can't load Database Driver", e); + } + } else { + // That will ensure that you are using the ClassLoader for you NAR. + this.driverClassLoader = Thread.currentThread().getContextClassLoader(); + } + } + + /** + * using Thread.currentThread().getContextClassLoader(); will ensure that + * you are using the ClassLoader for you NAR. + * + * @throws InitializationException + * if there is a problem obtaining the ClassLoader + */ Review comment: I guess this javadoc is just a remainder of the copy from `DBCPConnectionPool` and can be removed. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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