http://metrics.dropwizard.io/metrics-core: Metrics is a Java library which gives you unparalleled insight into what your code does in production. Metrics provides a powerful toolkit of ways to measure the behavior of critical components in your production environment.
  • Coda Hale
  • Ryan Tenney
  • Artem Prigoda 
public abstract class com.codahale.metrics.RatioGauge implements com.codahale.metrics.Gauge<java.lang.Double>
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: com.codahale.metrics.RatioGauge
  super_class: java.lang.Object
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.codahale.metrics.RatioGauge this
         0: .line 11
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.codahale.metrics.RatioGauge this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/codahale/metrics/RatioGauge;

  protected abstract com.codahale.metrics.RatioGauge$Ratio getRatio();
    descriptor: ()Lcom/codahale/metrics/RatioGauge$Ratio;
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT

  public java.lang.Double getValue();
    descriptor: ()Ljava/lang/Double;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.codahale.metrics.RatioGauge this
         0: .line 64
            aload 0 /* this */
            invokevirtual com.codahale.metrics.RatioGauge.getRatio:()Lcom/codahale/metrics/RatioGauge$Ratio;
            invokevirtual com.codahale.metrics.RatioGauge$Ratio.getValue:()D
            invokestatic java.lang.Double.valueOf:(D)Ljava/lang/Double;
            areturn
        end local 0 // com.codahale.metrics.RatioGauge this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/codahale/metrics/RatioGauge;

  public java.lang.Object getValue();
    descriptor: ()Ljava/lang/Object;
    flags: (0x1041) ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.codahale.metrics.RatioGauge.getValue:()Ljava/lang/Double;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Ljava/lang/Object;Lcom/codahale/metrics/Gauge<Ljava/lang/Double;>;
SourceFile: "RatioGauge.java"
NestMembers:
  com.codahale.metrics.RatioGauge$Ratio
InnerClasses:
  public Ratio = com.codahale.metrics.RatioGauge$Ratio of com.codahale.metrics.RatioGauge