io.opencensus.internal.Provider Maven / Gradle / Ivy
/*
* Copyright 2016-17, OpenCensus 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 io.opencensus.internal;
import java.util.ServiceConfigurationError;
/**
* OpenCensus service provider mechanism.
*
* {@code
* // Initialize a variable using reflection.
* foo = Provider.createInstance(
* Class.forName("FooImpl", true, classLoader), Foo.class);
* }
*/
public final class Provider {
private Provider() {}
/**
* Tries to create an instance of the given rawClass as a subclass of the given superclass.
*
* @param rawClass The class that is initialized.
* @param superclass The initialized class must be a subclass of this.
* @return an instance of the class given rawClass which is a subclass of the given superclass.
* @throws ServiceConfigurationError if any error happens.
*/
public static T createInstance(Class rawClass, Class superclass) {
try {
return rawClass.asSubclass(superclass).getConstructor().newInstance();
} catch (Exception e) {
throw new ServiceConfigurationError(
"Provider " + rawClass.getName() + " could not be instantiated.", e);
}
}
}