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/*
* 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.trace;
import io.opencensus.common.Clock;
import io.opencensus.internal.DefaultVisibilityForTesting;
import io.opencensus.internal.Provider;
import io.opencensus.trace.config.TraceConfig;
import io.opencensus.trace.export.ExportComponent;
import io.opencensus.trace.propagation.PropagationComponent;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Nullable;
/**
* Class that manages a global instance of the {@link TraceComponent}.
*
* @since 0.5
*/
public final class Tracing {
private static final Logger logger = Logger.getLogger(Tracing.class.getName());
private static final TraceComponent traceComponent =
loadTraceComponent(TraceComponent.class.getClassLoader());
/**
* Returns the global {@link Tracer}.
*
* @return the global {@code Tracer}.
* @since 0.5
*/
public static Tracer getTracer() {
return traceComponent.getTracer();
}
/**
* Returns the global {@link PropagationComponent}.
*
* @return the global {@code PropagationComponent}.
* @since 0.5
*/
public static PropagationComponent getPropagationComponent() {
return traceComponent.getPropagationComponent();
}
/**
* Returns the global {@link Clock}.
*
* @return the global {@code Clock}.
* @since 0.5
*/
public static Clock getClock() {
return traceComponent.getClock();
}
/**
* Returns the global {@link ExportComponent}.
*
* @return the global {@code ExportComponent}.
* @since 0.5
*/
public static ExportComponent getExportComponent() {
return traceComponent.getExportComponent();
}
/**
* Returns the global {@link TraceConfig}.
*
* @return the global {@code TraceConfig}.
* @since 0.5
*/
public static TraceConfig getTraceConfig() {
return traceComponent.getTraceConfig();
}
// Any provider that may be used for TraceComponent can be added here.
@DefaultVisibilityForTesting
static TraceComponent loadTraceComponent(@Nullable ClassLoader classLoader) {
try {
// Call Class.forName with literal string name of the class to help shading tools.
return Provider.createInstance(
Class.forName(
"io.opencensus.impl.trace.TraceComponentImpl", /*initialize=*/ true, classLoader),
TraceComponent.class);
} catch (ClassNotFoundException e) {
logger.log(
Level.FINE,
"Couldn't load full implementation for TraceComponent, now trying to load lite "
+ "implementation.",
e);
}
try {
// Call Class.forName with literal string name of the class to help shading tools.
return Provider.createInstance(
Class.forName(
"io.opencensus.impllite.trace.TraceComponentImplLite",
/*initialize=*/ true,
classLoader),
TraceComponent.class);
} catch (ClassNotFoundException e) {
logger.log(
Level.FINE,
"Couldn't load lite implementation for TraceComponent, now using "
+ "default implementation for TraceComponent.",
e);
}
return TraceComponent.newNoopTraceComponent();
}
// No instance of this class.
private Tracing() {}
}
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