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Guide to upgrading from OSHI 3.x to 4.x

OSHI 4.0 requires minimum Java 8 compatibility.

The oshi-json artifact has been completely removed. It is trivial to obtain JSON output using [Jackson's ObjectMapper](http://www.mkyong.com/java/ jackson-2-convert-java-object-to-from-json/).

There is a new oshi-demo artifact which will contain many "how to" classes to demonstrate OSHI's capabilities and integration with other libraries.

API Changes

Several changes in the API highlight which attributes do not change and which fetch dynamic information, as well as highlight operations with latency or expensive computations. In general the following rules are followed:

  • getX() (and isX() for boolean) are lazy getters for the initial data query, and will store the value in an attribute, returning that same value on subsequent calls. When relevant, an updateAtrributes() method will be available to cause the getters to return updated values.
  • queryX() will get the latest value and typically identify more expensive (in cpu or time) methods.

The following getX() methods are now queryX():

  • NetworkIF: getNetworkInterface() -> queryNetworkInterface() to prevent Jackson's ObjectMapper from attempting to serialize the returned object.

There is a new VirtualMemory class which is accessible with a getter from GlobalMemory. Methods associated with swap file usage were moved to this new class.

The CentralProcessor setters were removed from the API. The methods getSystemCpuLoadBetweenTicks() and getProcessorCpuLoadBetweenTicks() now take an argument with the previous set of ticks, rather than internally saving the previous call. This enables users to measure over a longer period or multiple different periods. The getSystemCpuLoad() method is now a direct passthrough to the OperatingSystemMXBean method if running an Oracle JVM, otherwise it returns a negative value. The no-argument getSystemLoadAverage() has been removed; users can call with an argument of 1 to obtain the same value.

Guide to upgrading from OSHI 2.x to 3.x

The most significant change in OSHI 3.0 is the separation of JSON output to a separate artifact, filtering output using configurable properties. Users of oshi-core who do not require JSON will find most of the API the same except as noted below. Those who use JSON will find improved functionality in the oshi-json module.

API Changes - oshi-core

The CentralProcessor's getSystemIOWaitTicks() and getSystemIrqTicks() methods were removed. The getSystemCpuLoadTicks() now include the IOWait and IRQ tick information previously reported by those methods, although Idle time no longer includes IOWait, and System Time no longer includes IRQ ticks. The getProcessorCpuLoadTicks() now includes per-processor IOWait and IRQ tick information.

The getFileSystem() method was moved from the HardwareAbstractionLayer to the OperatingSystem. The getFileStores() method on the HardwareAbstractionLayer was redundant with the same method on the FileSystem class and was removed.

The OSProcess methods (getProcesses(), getProcess(), getProcessId(), getProcessCount(), and getThreadCount()) were moved from the CentralProcessor to the OperatingSystem.

The (OperatingSystem's) getProcesses() method now takes two arguments, to limit the number of results returned, and to sort the results.

The HardwareAbstractionLayer's getUsbDevices() method now takes a boolean argument which offers both the existing tree-based or a flat list format.

The Networks interface had an updateNetworkStats() method that was not reachable from cross-platform code. That method is now on the NetworkIF class.

API Changes - oshi-json

Decorator classes for the OSHI API which enable JSON functionality are now in the oshi.json.* packages with the same API changes in the previous section.

JSON objects associated with the above method changes were updated:

  • systemCpuLoadTicks and processorCpuLoadTicks now have 7-element arrays instead of 4, and the systemIOWaitTicks and systemIrqTicks elements have been removed from the processor object.
  • fileSystem is now an element of operatingSystem rather than processor.
  • fileStores is now an element of fileSystem rather than processor.
  • processID, processCount, threadCount, and processes are now elements of operatingSystem rather than processor.

While the existing toJSON() method remains and is backwards compatible, the new API permits using a java.util.Properties object as an optional parameter which will be persistent to future (no argument) calls to that method until replaced. See the FAQ for more information.

Guide to upgrading from OSHI 1.x to 2.x

Even though it's a major release, OSHI 2.0 functionality is identical to 1.5.2. For the most part, the highest level APIs demonstrated in the test classes have remained the same, except as documented below. Several lower level packages and classes have been moved and/or renamed.

Package Changes

New packages oshi.jna.platform.* were created and code which extends com.sun.jna.Library was moved into its respective platform library. These classes should be considered non-API as they may be removed if/when their code is incorporated into the JNA project.

New packages oshi.hardware.platform.* were created and contain the platform-specific implementations of interfaces in oshi.hardware, with implementing classes renamed to prepend the platform name to the interface name. Similar renaming was done for implementations of oshi.software.os in the respective oshi.software.os.* packages.

API Changes

The Memory interface was renamed GlobalMemory to avoid name conflict with JNA's Memory class.

The Processor interface, which represented one of an array of logical processor objects, was renamed CentralProcessor and represents the entire System CPU which may contain multiple logical processors. Methods applicable to an individual logical processor were modified to return arrays.

The HardwareAbstractionLayer's getProcessors() method was renamed to getProcessor() and now returns a singular CentralProcessor object.

Specific changes to CentralProcessor methods:

  • The constructor no longer takes a processor number argument and the getProcessorNumber() method was removed
  • The deprecated getLoad() method was removed. Use getSystemCpuLoadBetweenTicks().
  • The getProcessorCpuLoadBetweenTicks() method now returns an array of load values, one value for each logical processor.
  • The getProcessorCpuLoadTicks() method now returns a two dimensional array; one array per logical processor, each containing the tick values previously returned for a single processor.