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Gradle 6.9.1 API redistribution.
/*
* Copyright 2012 the original author or authors.
*
* 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.
*/
package org.gradle.internal.service;
import org.gradle.api.reflect.ObjectInstantiationException;
import org.gradle.internal.Factory;
import org.gradle.internal.reflect.DirectInstantiator;
import javax.annotation.Nonnull;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* Uses the Jar service resource specification to locate service implementations.
*/
public class DefaultServiceLocator implements ServiceLocator {
private final boolean useCaches;
private final List classLoaders;
public DefaultServiceLocator(ClassLoader... classLoaders) {
this(true, classLoaders);
}
public DefaultServiceLocator(boolean useCaches, ClassLoader... classLoaders) {
this.useCaches = useCaches;
this.classLoaders = Arrays.asList(classLoaders);
}
@Override
public T get(Class serviceType) throws UnknownServiceException {
return getFactory(serviceType).create();
}
@Override
public List getAll(Class serviceType) throws UnknownServiceException {
List> factories = findFactoriesForServiceType(serviceType);
ArrayList services = new ArrayList();
for (ServiceFactory factory : factories) {
services.add(factory.create());
}
return services;
}
@Override
public ServiceFactory getFactory(final Class serviceType) throws UnknownServiceException {
ServiceFactory factory = findFactory(serviceType);
if (factory == null) {
throw new UnknownServiceException(serviceType, String.format("Could not find meta-data resource 'META-INF/services/%s' for service '%s'.", serviceType.getName(), serviceType.getName()));
}
return factory;
}
/**
* Locates a factory for a given service. Returns null when no service implementation is available.
*/
@Override
public ServiceFactory findFactory(Class serviceType) {
List> factories = findFactoriesForServiceType(serviceType);
if (factories.isEmpty()) {
return null;
}
return factories.get(0);
}
/**
* Locates and class load implementation classes for a given service.
*/
public List> implementationsOf(Class serviceType) {
try {
return findServiceImplementations(serviceType);
} catch (ServiceLookupException e) {
throw e;
} catch (Exception e) {
throw new ServiceLookupException(String.format("Could not determine implementation classes for service '%s'.", serviceType.getName()), e);
}
}
private List> findFactoriesForServiceType(Class serviceType) {
return factoriesFor(serviceType, implementationsOf(serviceType));
}
private List> factoriesFor(Class serviceType, List> implementationClasses) {
List> factories = new ArrayList>();
for (Class implementationClass : implementationClasses) {
factories.add(new ServiceFactory(serviceType, implementationClass));
}
return factories;
}
private List> findServiceImplementations(Class serviceType) throws IOException {
String resourceName = "META-INF/services/" + serviceType.getName();
Set implementationClassNames = new HashSet();
List> implementations = new ArrayList>();
for (ClassLoader classLoader : classLoaders) {
Enumeration resources = classLoader.getResources(resourceName);
while (resources.hasMoreElements()) {
URL resource = resources.nextElement();
List implementationClassNamesFromResource;
try {
implementationClassNamesFromResource = extractImplementationClassNames(resource);
if (implementationClassNamesFromResource.isEmpty()) {
throw new RuntimeException(String.format("No implementation class for service '%s' specified.", serviceType.getName()));
}
} catch (Throwable e) {
throw new ServiceLookupException(String.format("Could not determine implementation class for service '%s' specified in resource '%s'.", serviceType.getName(), resource), e);
}
for (String implementationClassName : implementationClassNamesFromResource) {
if (implementationClassNames.add(implementationClassName)) {
try {
Class implClass = classLoader.loadClass(implementationClassName);
if (!serviceType.isAssignableFrom(implClass)) {
throw new RuntimeException(String.format("Implementation class '%s' is not assignable to service class '%s'.", implementationClassName, serviceType.getName()));
}
implementations.add(implClass.asSubclass(serviceType));
} catch (Throwable e) {
throw new ServiceLookupException(String.format("Could not load implementation class '%s' for service '%s' specified in resource '%s'.", implementationClassName, serviceType.getName(), resource), e);
}
}
}
}
}
return implementations;
}
private List extractImplementationClassNames(URL resource) throws IOException {
URLConnection urlConnection = resource.openConnection();
if (!useCaches && urlConnection instanceof JarURLConnection) {
urlConnection.setUseCaches(false);
}
InputStream inputStream = urlConnection.getInputStream();
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
List implementationClassNames = new ArrayList();
String line;
while ((line = reader.readLine()) != null) {
line = line.replaceAll("#.*", "").trim();
if (line.length() > 0) {
implementationClassNames.add(line);
}
}
return implementationClassNames;
} finally {
inputStream.close();
}
}
public static class ServiceFactory implements Factory {
private final Class serviceType;
private final Class implementationClass;
public ServiceFactory(Class serviceType, Class implementationClass) {
this.serviceType = serviceType;
this.implementationClass = implementationClass;
}
public Class getImplementationClass() {
return implementationClass;
}
@Override
@Nonnull
public T create() {
return newInstance();
}
public T newInstance(Object... params) {
try {
return DirectInstantiator.instantiate(implementationClass, params);
} catch (ObjectInstantiationException t) {
throw new RuntimeException(String.format("Could not create an implementation of service '%s'.", serviceType.getName()), t);
}
}
}
}