Profiler.java

package org.stagemonitor.tracing.profiler;

import org.stagemonitor.core.Stagemonitor;
import org.stagemonitor.tracing.TracingPlugin;

public final class Profiler {

	public static final long MIN_EXECUTION_TIME_NANOS = Stagemonitor.getPlugin(TracingPlugin.class).getMinExecutionTimeNanos();

	private static final ThreadLocal<CallStackElement> methodCallParent = new ThreadLocal<CallStackElement>();

	private Profiler() {
	}

	public static void start(String signature) {
		final CallStackElement parent = methodCallParent.get();
		if (parent != null) {
			methodCallParent.set(CallStackElement.create(parent, signature));
		}
	}

	public static void stop() {
		final CallStackElement currentElement = methodCallParent.get();
		if (currentElement != null) {
			methodCallParent.set(currentElement.executionStopped(System.nanoTime(), MIN_EXECUTION_TIME_NANOS));
		}
	}

	public static void addIOCall(String signature, long executionTimeNanos) {
		addCall(signature + ' ', executionTimeNanos);
	}

	public static void addCall(String signature, long executionTimeNanos) {
		final CallStackElement currentCall = methodCallParent.get();
		CallStackElement.create(currentCall, signature, executionTimeNanos);
	}

	public static boolean isProfilingActive() {
		return methodCallParent.get() != null;
	}

	/**
	 * Activates the profiling for the current thread by setting the provided
	 * {@link CallStackElement} as the root of the call stack
	 *
	 * @return the root of the call stack
	 */
	public static CallStackElement activateProfiling(String signature) {
		CallStackElement root = CallStackElement.createRoot(signature);
		methodCallParent.set(root);
		return root;
	}

	public static void deactivateProfiling() {
		methodCallParent.set(null);
	}

	/**
	 * Adds the current
	 * @return
	 */
	public static CallStackElement getMethodCallParent() {
		return methodCallParent.get();
	}

	public static void clearMethodCallParent() {
		methodCallParent.remove();
	}
}