Collects the Buffers parameter, which is the amount of memory that is used as a relatively temporary storage for raw disk blocks.

Collects the SwapCached parameter, which is the amount of swap space used as cache memory - memory that has once been moved into swap, then back into the main memory, but still also remains in the swapfile.

Collects the MemFree parameter, which is the amount of physical RAM left unused by the system.

Collects the SwapFree parameter, which is the amount of swap space currently unused - the memory that has been transferred from RAM to the disk temporarily.

Collects the Shmem parameter - the amount of memory located either for processes with separate address spaces that are sharing a portion of memory, or for tmpfs(5) filesystems, whose contents reside in virtual memory to speed up file access.

Collects the MemTotal parameter, which is the total usable RAM (i.e., physical RAM minus a few reserved bits and the kernel binary code).

Collects the SwapTotal parameter, which is the total amount of swap space available on the disk - when the physical memory is full, the system uses the swap space.

Calculates the total used memory, by collecting the MemTotal parameter - the total usable RAM (i.e., physical RAM minus a few reserved bits and the kernel binary code) - and the MemFree parameter - the amount of physical RAM left unused by the system -, returning the subtraction of the value of the latter out of the first.

Calculates the used swap memory by collecting the SwapTotal parameter - the total amount of swap space available on the disk - and the SwapFree parameter - the total amount of swap space currently unused -, returning the subtraction of the value of the latter out of the first.

Creates a Dropwizard's Gauge metric type - an instantaneous reading of a particular value -, setting the provided collector method as the getValue method of the Gauge instance.

Returns the plugin's driver-side component. The returned DriverPlugin instance is called once, early in the initialization of the Spark driver. The operation it performs consists in the sequential registration of each mapped metric as a Gauge metric into an existing metric Registry. A test call is executed once on each collector method before its registration, assuring that the metric is available to be read and collected from the local OS, thus preventing future errors when the Gauge is first executed by the metrics system. If a NoSuchElementException is thrown in this attempt, the method is not registered, enabling the registration of the subsequent mapped metrics by the plugin. The plugin component ends its execution once all metrics are registered, leaving to the Dropwizard's Metrics system the job of collecting and exporting the registered metrics in a pre or user-defined frequency.

Returns the plugin's executor-side component. The returned ExecutorPlugin instance is called once, early in the initialization of the executor process. The operation it performs consists in the sequential registration of each mapped metric as a Gauge metric into an existing metric Registry. A test call is executed once on each collector method before its registration, assuring that the metric is available to be read and collected from the local OS, thus preventing future errors when the Gauge is first executed by the metrics system. If a NoSuchElementException is thrown in this attempt, the method is not registered, enabling the registration of the subsequent mapped metrics by the plugin. The plugin component ends its execution once all metrics are registered, leaving to the Dropwizard's Metrics system the job of collecting and exporting the registered metrics in a pre or user-defined frequency.

Registers a provided Dropwizard's Metric instance into a metric registry under a metric name.