ClassUtils.java
/*-
* ========================LICENSE_START=================================
* flyway-core
* ========================================================================
* Copyright (C) 2010 - 2025 Red Gate Software Ltd
* ========================================================================
* 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.flywaydb.core.internal.util;
import java.lang.reflect.InvocationTargetException;
import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import org.flywaydb.core.api.FlywayException;
import java.io.File;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.ServiceLoader;
import java.util.TreeMap;
import java.util.stream.Collectors;
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public class ClassUtils {
/**
* Creates a new instance of this class.
*
* @param className The fully qualified name of the class to instantiate.
* @param classLoader The ClassLoader to use.
* @return The new instance.
* @throws FlywayException Thrown when the instantiation failed.
*/
@SuppressWarnings({"unchecked"})
public static <T> T instantiate(String className, ClassLoader classLoader) {
try {
return (T) Class.forName(className, true, classLoader).getDeclaredConstructor().newInstance();
} catch (Exception e) {
throw new FlywayException("Unable to instantiate class " + className + " : " + e.getMessage(), e);
}
}
/**
* Determine whether the {@link Class} identified by the supplied name is present
* and can be loaded. Will return {@code false} if either the class or
* one of its dependencies is not present or cannot be loaded.
*
* @param className The name of the class to check.
* @param classLoader The ClassLoader to use.
* @return whether the specified class is present
*/
public static boolean isPresent(String className, ClassLoader classLoader) {
try {
classLoader.loadClass(className);
return true;
} catch (Throwable ex) {
// Class or one of its dependencies is not present...
return false;
}
}
/**
* Determine whether a class implementing the service identified by the supplied name is present
* and can be loaded. Will return {@code false} if either no class is found, or the class or
* one of its dependencies is not present or cannot be loaded.
*
* @param serviceName The name of the service to check.
* @param classLoader The ClassLoader to use.
* @return whether an implementation of the specified service is present
*/
public static boolean isImplementationPresent(String serviceName, ClassLoader classLoader) {
try {
Class service = classLoader.loadClass(serviceName);
return ServiceLoader.load(service).iterator().hasNext();
} catch (Throwable ex) {
// Class or one of its dependencies is not present...
return false;
}
}
/**
* Loads the class with this name using the class loader.
*
* @param implementedInterface The interface the class is expected to implement.
* @param className The name of the class to load.
* @param classLoader The ClassLoader to use.
* @return the newly loaded class or {@code null} if it could not be loaded.
* @throws Exception Skip if exception thrown
*/
public static <I> Class<? extends I> loadClass(Class<I> implementedInterface, String className, ClassLoader classLoader) throws Exception {
Class<?> clazz = classLoader.loadClass(className);
if (!implementedInterface.isAssignableFrom(clazz)) {
return null;
}
if (Modifier.isAbstract(clazz.getModifiers()) || clazz.isEnum() || clazz.isAnonymousClass()) {
return null;
}
clazz.getDeclaredConstructor().newInstance();
//noinspection unchecked
return (Class<? extends I>) clazz;
}
public static String formatThrowable(Throwable e) {
return "(" + e.getClass().getSimpleName() + ": " + e.getMessage() + ")";
}
/**
* Retrieves the physical location on disk of this class.
*
* @param aClass The class to get the location for.
* @return The absolute path of the .class file.
*/
public static String getLocationOnDisk(Class<?> aClass) {
ProtectionDomain protectionDomain = aClass.getProtectionDomain();
if (protectionDomain == null) {
return null;
}
CodeSource codeSource = protectionDomain.getCodeSource();
if (codeSource == null || codeSource.getLocation() == null) {
//Custom classloader with for example classes defined using URLClassLoader#defineClass(String name, byte[] b, int off, int len)
return null;
}
return UrlUtils.decodeURLSafe(codeSource.getLocation().getPath());
}
public static String getLibDir(Class<?> clazz) {
String classLocation = Objects.requireNonNull(ClassUtils.getLocationOnDisk(clazz));
return new File(classLocation) // jar file
.getParentFile() // edition dir
.getParentFile() // lib dir
.getAbsolutePath();
}
public static String getInstallDir(Class<?> clazz) {
String path = Objects.requireNonNull(ClassUtils.getLocationOnDisk(clazz));
return new File(path) // jar file
.getParentFile() // edition dir
.getParentFile() // lib dir
.getParentFile() // installation dir
.getAbsolutePath();
}
/**
* Adds these jars or directories to the classpath.
*
* @param classLoader The current ClassLoader.
* @param jarFiles The jars or directories to add.
* @return The new ClassLoader containing the additional jar or directory.
*/
public static ClassLoader addJarsOrDirectoriesToClasspath(ClassLoader classLoader, List<File> jarFiles) {
List<URL> urls = new ArrayList<>();
for (File jarFile : jarFiles) {
try {
urls.add(jarFile.toURI().toURL());
} catch (Exception e) {
throw new FlywayException("Unable to load " + jarFile.getPath(), e);
}
}
return new URLClassLoader(urls.toArray(new URL[0]), classLoader);
}
/**
* Gets the String value of a static field.
*
* @param className The fully qualified name of the class to instantiate.
* @param fieldName The field name.
* @param classLoader The ClassLoader to use.
* @return The value of the field.
* @throws FlywayException Thrown when the instantiation failed.
*/
public static String getStaticFieldValue(String className, String fieldName, ClassLoader classLoader) {
try {
Class clazz = Class.forName(className, true, classLoader);
Field field = clazz.getField(fieldName);
return (String) field.get(null);
} catch (Exception e) {
throw new FlywayException("Unable to obtain field value " + className + "." + fieldName + " : " + e.getMessage(), e);
}
}
public static Object getFieldValue(Object obj, String fieldName) {
try {
Field field = obj.getClass().getDeclaredField(fieldName);
field.setAccessible(true);
return field.get(obj);
} catch (Exception e) {
throw new FlywayException("Unable to obtain field value " + obj.getClass().getName() + "." + fieldName + " : " + e.getMessage(), e);
}
}
public static void setFieldValue(Object obj, String fieldName, Object value) {
try {
Field field = obj.getClass().getDeclaredField(fieldName);
field.setAccessible(true);
field.set(obj, value);
} catch (Exception e) {
throw new FlywayException("Unable to set field value " + obj.getClass().getName() + "." + fieldName + " : " + e.getMessage(), e);
}
}
public static List<String> getGettableField(final Object obj) {
return getGettableField(obj, "");
}
public static List<String> getGettableField(final Object obj, final String prefix) {
List<String> fields = new ArrayList<>();
Class<?> clazz = obj.getClass();
while (clazz != null) {
for (Method method : Arrays.stream(clazz.getDeclaredMethods()).filter(m -> m.getName().startsWith("get")
&& Arrays.stream(m.getAnnotations()).noneMatch(a -> a instanceof DoNotMapForLogging)
&& !m.getName().equals("getClass")).toList()) {
method.setAccessible(true);
String name = method.getName().substring(3, 4).toLowerCase() + method.getName().substring(4);
fields.add(prefix + name);
}
clazz = clazz.getSuperclass();
}
return fields;
}
public static Map<String, String> getGettableFieldValues(final Object obj, final String prefix) {
Map<String, String> fieldValues = new TreeMap<>();
Class<?> clazz = obj.getClass();
while (clazz != null) {
for (Method method : Arrays.stream(clazz.getDeclaredMethods()).filter(m -> m.getName().startsWith("get")
&& Arrays.stream(m.getAnnotations()).noneMatch(a -> a instanceof DoNotMapForLogging)
&& !m.getName().equals("getClass")).toList()) {
try {
method.setAccessible(true);
String name = method.getName().substring(3, 4).toLowerCase() + method.getName().substring(4);
fieldValues.put(prefix + name, method.invoke(obj).toString());
} catch (Exception ignored) {
}
}
clazz = clazz.getSuperclass();
}
return fieldValues;
}
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface DoNotMapForLogging {
}
}