src/main/java/org/cloudera/htrace/impl/TrueIfTracingSampler.java

package org.cloudera.htrace.impl;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.cloudera.htrace.Sampler;
import org.cloudera.htrace.Trace;

/**
 * A Sampler that returns true if and only if tracing is on the current thread.
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class TrueIfTracingSampler implements Sampler<Object> {

  private static TrueIfTracingSampler instance;

  public static TrueIfTracingSampler getInstance() {
    if (instance == null) {
      instance = new TrueIfTracingSampler();
    }
    return instance;
  }

  private TrueIfTracingSampler() {
  }

  @Override
  public boolean next(Object info) {
    return Trace.isTracing();
  }

}