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Merge pull request #8289 from mandy-chessell/oak2024
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Add custom class loader to OCF (#8288)
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mandy-chessell authored Jul 18, 2024
2 parents e7eeae7 + f68dcc7 commit bcbf4ad
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Showing 5 changed files with 225 additions and 8 deletions.
4 changes: 2 additions & 2 deletions bom/build.gradle
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Expand Up @@ -24,7 +24,7 @@ ext {
antlrVersion = '3.5.3'
ST4Version = '4.3.4'
avroVersion = '1.11.3'
xtdbVersion = '1.24.3'
xtdbVersion = '1.24.4'
clojureVersion = '1.11.1'
classgraphVersion = '4.8.172'
classmateVersion = '1.5.1'
Expand Down Expand Up @@ -75,7 +75,7 @@ ext {
lang3Version = '3.14.0'
logbackVersion = '1.5.6'
lettuceVersion = '6.3.2.RELEASE'
// TODO: Version 9 now available
// TODO: Lucene Version 9 now available but changed the naming of Codec files and so does not work with XTDB
luceneVersion = '8.11.3'
openlineageVersion = '1.16.0'
ossVersion = '4.16.0'
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Expand Up @@ -5,15 +5,15 @@
import org.odpi.openmetadata.frameworks.auditlog.AuditLog;
import org.odpi.openmetadata.frameworks.auditlog.AuditLoggingComponent;
import org.odpi.openmetadata.frameworks.auditlog.ComponentDescription;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.odpi.openmetadata.frameworks.connectors.ffdc.ConnectionCheckedException;
import org.odpi.openmetadata.frameworks.connectors.ffdc.ConnectorCheckedException;
import org.odpi.openmetadata.frameworks.connectors.ffdc.OCFErrorCode;
import org.odpi.openmetadata.frameworks.connectors.properties.ConnectionProperties;
import org.odpi.openmetadata.frameworks.connectors.properties.ConnectorTypeProperties;
import org.odpi.openmetadata.frameworks.connectors.properties.beans.Connection;
import org.odpi.openmetadata.frameworks.connectors.properties.beans.ConnectorType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.List;
Expand All @@ -22,12 +22,10 @@
/**
* ConnectorProviderBase is a base class for a connector provider. It manages all the class loading
* for subclass implementations of the connector provider along with the generation of new connector guids.
*
* ConnectorProviderBase creates a connector instance with the class name from the private variable called
* connectorClassName. This class name is initialized to null. If the getConnector method is called when
* the connectorClassName is null, it throws ConnectorCheckedException.
* This is its default behaviour.
*
* To use the ConnectorProviderBase, create a new class that extends the ConnectorProviderBase class
* and in the constructor call super.setConnectorClassName("your connector's class name");
*/
Expand Down Expand Up @@ -333,7 +331,7 @@ public Connector getConnector(ConnectionProperties connection) throws Connection
*/
try
{
Class<?> connectorClass = Class.forName(connectorClassName);
Class<?> connectorClass = getClassForConnector();
Object potentialConnector = connectorClass.getDeclaredConstructor().newInstance();

connector = (Connector)potentialConnector;
Expand Down Expand Up @@ -406,6 +404,18 @@ public Connector getConnector(ConnectionProperties connection) throws Connection
}


/**
* Use the standard class loader to retrieve the class for the connector.
*
* @return class
* @throws ClassNotFoundException unable to locate a class by that name on the class path
*/
protected Class<?> getClassForConnector() throws ClassNotFoundException
{
return Class.forName(connectorClassName);
}


/**
* Provide a common implementation of hashCode for all OCF Connector Provider objects. The UUID is unique and
* is randomly assigned and so its hashCode is as good as anything to describe the hash code of the properties
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@@ -0,0 +1,75 @@
/* SPDX-License-Identifier: Apache-2.0 */
/* Copyright Contributors to the ODPi Egeria project. */

package org.odpi.openmetadata.frameworks.connectors;


import java.io.*;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.jar.JarFile;

/**
* IsolatedConnectorClassLoader is used by a connector provider to create a connector instance that uses class
* implementations from its own JAR file rather than any class implementations that may have already been loaded.
*/
public class IsolatedConnectorClassLoader extends URLClassLoader
{
private final ClassLoader defaultClassLoader;
private final JarFile jarfile;
private final String jarFileName;
private final String jarFileSpec;


public IsolatedConnectorClassLoader(String jarFileName) throws IOException
{
this(jarFileName,
Thread.currentThread().getContextClassLoader().getParent(),
Thread.currentThread().getContextClassLoader());
}


/**
* Creates a new class loader of the specified name and using the
* specified parent class loader for delegation.
*
* @param jarFileName name of the jar file to load from
* @param jdkClassLoader the parent class loader for JRE classes
* @param defaultClassLoader the class loader to use if can not find class in JAR.
*/
protected IsolatedConnectorClassLoader(String jarFileName,
ClassLoader jdkClassLoader,
ClassLoader defaultClassLoader) throws IOException
{
super(new URL[]{}, jdkClassLoader);
this.defaultClassLoader = defaultClassLoader;
this. jarFileName = jarFileName;
this.jarfile = new JarFile(jarFileName);
super.addURL(new File(jarFileName).toURI().toURL());

this.jarFileSpec = "jar:file:" + jarFileName + "!/";
super.addURL(new URL(jarFileSpec));
}


/**
* This loads classes from the JDK, then the JAR file, then the default class loader.
*
* @param name The <a href="#binary-name">binary name</a> of the class
*
* @return loaded class
* @throws ClassNotFoundException not found on the class path
*/
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException
{
try
{
return super.findClass(name);
}
catch (ClassNotFoundException notFound)
{
return defaultClassLoader.loadClass(name);
}
}
}
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@@ -0,0 +1,133 @@
/* SPDX-License-Identifier: Apache-2.0 */
/* Copyright Contributors to the ODPi Egeria project. */

package org.odpi.openmetadata.frameworks.connectors;


import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Paths;

/**
* IsolatedConnectorProviderBase provides extensions to ConnectorProviderBase that uses a custom class loader to
* load the connector class in getConnector. This custom class loader give preference to the classes in the
* same JAR file as the connector provider's implementation over other classes on the class path.
* Note:
* this process assumes that the connector class is not already loaded through a reference in the connector providers
* implementation - ie private static final String connectorClassName should be set to a literal string.
*
*/
public class IsolatedConnectorProviderBase extends ConnectorProviderBase
{

/**
* Use a custom class loader to favour classes that are located in the connector implementation's JAR file.
*
* @return class
* @throws ClassNotFoundException unable to locate a class by that name on the class path
*/
protected Class<?> getClassForConnector() throws ClassNotFoundException
{
try
{
IsolatedConnectorClassLoader isolatedConnectorClassLoader = new IsolatedConnectorClassLoader(this.getJARFileURL(this.getClass()));

// return Class.forName(getConnectorClassName(), true, isolatedConnectorClassLoader);

return isolatedConnectorClassLoader.loadClass(getConnectorClassName());
}
catch (IOException error)
{
throw new ClassNotFoundException("Bad provider class name", error);
}
}


/**
* Extract the name of the JAR file from the provider's class.
*
* @param providerClass class for this connector provider
* @return JAR file name in URL form
* @throws MalformedURLException should not happen - this means the class was not loaded from a JAR file.
*/
private String getJARFileURL(Class<?> providerClass) throws MalformedURLException
{
URL qualifiedClassURL = providerClass.getResource(providerClass.getSimpleName() + ".class");

if (qualifiedClassURL != null)
{
String qualifiedClassName = qualifiedClassURL.toString();
String noClassQualifiedName = qualifiedClassName.split("!")[0];
String[] noJarQualifiedNameSplit = noClassQualifiedName.split("jar:file:");

String noJarQualifiedName = noJarQualifiedNameSplit[noJarQualifiedNameSplit.length - 1];

return noJarQualifiedName;
}

return null;
}


/**
* Return the path name of the Connector Provider's JAR file.
*
* @return file name of this connector provider's jar file
*/
private String getMyJARFilePath()
{
try
{
return byGetProtectionDomain(this.getClass());
}
catch (Exception error)
{
// Cannot get jar file path using byGetProtectionDomain because the runtime does not permit it
}

return byGetResource(this.getClass());
}



/**
* This method
* @param providerClass
* @return
* @throws URISyntaxException
*/
String byGetProtectionDomain(Class<?> providerClass) throws URISyntaxException
{
URL url = providerClass.getProtectionDomain().getCodeSource().getLocation();
return Paths.get(url.toURI()).toString();
}

String byGetResource(Class<?> providerClass)
{
final URL classResource = providerClass.getResource(providerClass.getSimpleName() + ".class");
if (classResource == null)
{
throw new RuntimeException("class resource is null");
}

final String url = classResource.toString();
if (url.startsWith("jar:file:"))
{
// extract 'file:......jarName.jar' part from the url string
String path = url.replaceAll("^jar:(file:.*[.]jar)!/.*", "$1");
try
{
return Paths.get(new URI(path)).toString();
}
catch (Exception error)
{
throw new RuntimeException("Invalid Jar File URL String", error);
}
}

throw new RuntimeException("Invalid Jar File URL String");
}
}
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Expand Up @@ -9,7 +9,6 @@
* The OMRSRepositoryConnectorProviderBase provides a base class for the connector provider supporting OMRS Connectors.
* It adds no function but provides a placeholder for additional function if needed for the creation of
* any OMRS Repository connectors.
*
* It extends ConnectorProviderBase which does the creation of connector instances. The subclasses of
* OMRSRepositoryConnectorProviderBase must initialize ConnectorProviderBase with the Java class
* name of the OMRS Connector implementation (by calling super.setConnectorClassName(className)).
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