Use Metrics libraries for HTTP serving and JSON serialization

Gemfile

@@ -1,6 +1,7 @@
 source 'https://rubygems.org/'
 
-gemspec
+gemspec name: 'multimeter'
+gemspec name: 'multimeter-http'
 
 group :examples do
   gem 'rack'

Rakefile

@@ -14,7 +14,7 @@ Rake::JavaExtensionTask.new('multimeter_metrics') do |ext|
 end
 
 namespace :bundler do
-  Bundler::GemHelper.install_tasks
+  Bundler::GemHelper.install_tasks(name: 'multimeter')
 end
 
 task :release => [:spec, :compile, 'bundler:release']

ext/java/MultimeterMetricsService.java

@@ -10,6 +10,7 @@
 import multimeter.Histogram;
 import multimeter.Snapshot;
 import multimeter.Gauge;
+import multimeter.JSONSerializer;
 
 public class MultimeterMetricsService implements BasicLibraryService {
   public boolean basicLoad(final Ruby runtime) throws IOException {
@@ -20,6 +21,7 @@ public boolean basicLoad(final Ruby runtime) throws IOException {
     Histogram.setup(runtime);
     Snapshot.setup(runtime);
     Gauge.setup(runtime);
+    JSONSerializer.setup(runtime);
     return true;
   }
 }

ext/java/multimeter/Counter.java

@@ -6,12 +6,14 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
 import org.jruby.runtime.ObjectAllocator;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.javasupport.JavaUtil;
 
 import static org.jruby.runtime.Visibility.PRIVATE;
 
@@ -30,6 +32,16 @@ public Counter(Ruby runtime, com.codahale.metrics.Counter counter) {
     this.counter = counter;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, counter);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, counter);
+  }
+
   @JRubyMethod
   public IRubyObject count(ThreadContext ctx) {
     return ctx.runtime.newFixnum(counter.getCount());

ext/java/multimeter/Gauge.java

@@ -6,6 +6,7 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
@@ -31,6 +32,16 @@ public Gauge(Ruby runtime, com.codahale.metrics.Gauge<? extends Object> gauge) {
     this.gauge = gauge;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, gauge);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, gauge);
+  }
+
   @JRubyMethod
   public IRubyObject value(ThreadContext ctx) {
     Object value = gauge.getValue();

ext/java/multimeter/Histogram.java

@@ -6,12 +6,14 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
 import org.jruby.runtime.ObjectAllocator;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.javasupport.JavaUtil;
 
 import static org.jruby.runtime.Visibility.PRIVATE;
 
@@ -30,6 +32,16 @@ public Histogram(Ruby runtime, com.codahale.metrics.Histogram histogram) {
     this.histogram = histogram;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, histogram);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, histogram);
+  }
+
   @JRubyMethod
   public IRubyObject count(ThreadContext ctx) {
     return ctx.runtime.newFixnum(histogram.getCount());

ext/java/multimeter/JSONSerializer.java

@@ -0,0 +1,55 @@
+package multimeter;
+
+import com.codahale.metrics.json.MetricsModule;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+import org.jruby.Ruby;
+import org.jruby.RubyClass;
+import org.jruby.RubyException;
+import org.jruby.exceptions.RaiseException;
+import org.jruby.RubyModule;
+import org.jruby.RubyString;
+import org.jruby.anno.JRubyClass;
+import org.jruby.runtime.ThreadContext;
+
+public class JSONSerializer {
+  private ObjectMapper mapper;
+  private MetricsModule module;
+
+  public static void setup(Ruby runtime) {
+    RubyModule multimeterModule = runtime.defineModule("Multimeter");
+    RubyClass standardError = runtime.getStandardError();
+    multimeterModule.defineClassUnder("JSONError", standardError, standardError.getAllocator());
+  }
+
+  @JRubyClass(name="Multimeter::JSONError", parent="StandardError")
+  public static class JSONError {}
+
+  private static JSONSerializer instance;
+
+  public static JSONSerializer getInstance() {
+    if ( instance == null ) {
+      instance = new JSONSerializer();
+    }
+    return instance;
+  }
+
+  private JSONSerializer() {
+    this.mapper = new ObjectMapper();
+    this.module = new MetricsModule(TimeUnit.SECONDS, TimeUnit.MILLISECONDS, false);
+    mapper.registerModule(module);
+  }
+
+  public RubyString serialize(ThreadContext ctx, Object object) {
+    ByteArrayOutputStream stream = new ByteArrayOutputStream();
+    try {
+      mapper.writeValue(stream, object);
+      return RubyString.newString(ctx.runtime, stream.toByteArray());
+    } catch (IOException e) {
+      RubyClass jsonError = ctx.runtime.getModule("Multimeter").getClass("JSONError");
+      throw new RaiseException(RubyException.newException(ctx.runtime, jsonError, e.toString()), false);
+    }
+  }
+}

ext/java/multimeter/Meter.java

@@ -6,12 +6,14 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
 import org.jruby.runtime.ObjectAllocator;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.javasupport.JavaUtil;
 
 import static org.jruby.runtime.Visibility.PRIVATE;
 
@@ -30,6 +32,16 @@ public Meter(Ruby runtime, com.codahale.metrics.Meter meter) {
     this.meter = meter;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, meter);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, meter);
+  }
+
   @JRubyMethod
   public IRubyObject count(ThreadContext ctx) {
     return ctx.runtime.newFixnum(meter.getCount());

ext/java/multimeter/MetricRegistry.java

@@ -49,6 +49,11 @@ public IRubyObject toJava(ThreadContext ctx) {
     return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, registry);
   }
 
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, registry);
+  }
+
   @JRubyMethod
   public IRubyObject metrics(ThreadContext ctx) {
     return metrics.dup(ctx);

ext/java/multimeter/Snapshot.java

@@ -6,12 +6,14 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
 import org.jruby.runtime.ObjectAllocator;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.javasupport.JavaUtil;
 
 import static org.jruby.runtime.Visibility.PRIVATE;
 
@@ -30,6 +32,16 @@ public Snapshot(Ruby runtime, com.codahale.metrics.Snapshot snapshot) {
     this.snapshot = snapshot;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, snapshot);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, snapshot);
+  }
+
   @JRubyMethod
   public IRubyObject size(ThreadContext ctx) {
     return ctx.runtime.newFixnum(snapshot.size());

ext/java/multimeter/Timer.java

@@ -6,12 +6,14 @@
 import org.jruby.RubyObject;
 import org.jruby.RubyHash;
 import org.jruby.RubyArray;
+import org.jruby.RubyString;
 import org.jruby.anno.JRubyClass;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.Block;
 import org.jruby.runtime.ObjectAllocator;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.javasupport.JavaUtil;
 
 import static org.jruby.runtime.Visibility.PRIVATE;
 
@@ -35,6 +37,16 @@ public Timer(Ruby runtime, com.codahale.metrics.Timer timer) {
     this.timer = timer;
   }
 
+  @JRubyMethod(name="to_java")
+  public IRubyObject toJava(ThreadContext ctx) {
+    return JavaUtil.convertJavaToUsableRubyObject(ctx.runtime, timer);
+  }
+
+  @JRubyMethod(name="to_json")
+  public RubyString toJson(ThreadContext ctx) {
+    return JSONSerializer.getInstance().serialize(ctx, timer);
+  }
+
   @JRubyMethod
   public IRubyObject count(ThreadContext ctx) {
     return ctx.runtime.newFixnum(timer.getCount());