Create a Simple Groovy TimeWatch for Accurate Performance Timing

Overview

TimeWatch is a lightweight Groovy utility designed to record execution times of code blocks in Java‑based projects. It offers a simple API for starting a timer, creating named or default markers, and retrieving elapsed durations in both milliseconds and nanoseconds.

Key Features (v1.0)

Static factory methods create() and create(name) that instantiate a timer and start it immediately.

Automatic capture of the start moment in nanoseconds ( startTime) and milliseconds ( startTimeMillis).

Marker management via mark(name) and mark(), storing each marker in a HashMap<String, Mark>.

Retrieval of marker elapsed time:

Total elapsed time since timer creation via getTime() (ms) and getNanoTime() (ns).

Clone support to duplicate a timer’s state.

Typical Usage

import com.fun.utils.TimeWatch

// Create a timer with the default name
TimeWatch watch = TimeWatch.create()

// Perform some work
doSomething()

// Record a named marker
watch.mark('step1')

// More work
doAnotherThing()

// Retrieve elapsed times
watch.getMarkTime('step1')          // logs milliseconds for 'step1'
watch.getMarkNanoTime('step1')     // logs nanoseconds for 'step1'
watch.getTime()                    // total elapsed time in ms
watch.getNanoTime()                // total elapsed time in ns

Implementation Details

The class extends SourceCode (a project‑specific base) and uses org.slf4j.LoggerFactory for logging. Each Mark instance records its own start time in both nanoseconds and milliseconds, allowing independent measurement of multiple points within the same execution flow.

Formatting of nanosecond values uses java.text.DecimalFormat to insert thousand separators for readability.

Future Enhancements

Thread‑safety: current implementation stores markers in a plain HashMap, which is not safe for concurrent access. A concurrent map or synchronization will be added.

Compatibility checks for environments where System.nanoTime() may behave differently.

Groovy Compatibility Note

Because Groovy runs on the JVM, the utility can be compiled and used directly in any Java project. Most Groovy source files can be renamed to .java and compiled without modification, and vice‑versa, making integration straightforward. Modern IDEs such as IntelliJ IDEA provide full Groovy support, and build tools like Gradle can compile the class without additional configuration.