com.palantir.giraffe.command.spi

Class ExecutionSystemProvider

java.lang.Object

com.palantir.giraffe.command.spi.ExecutionSystemProvider

All Implemented Interfaces:

com.palantir.giraffe.internal.SchemeIdentifiable

public abstract class ExecutionSystemProvider
extends Object
implements com.palantir.giraffe.internal.SchemeIdentifiable

Service provider class for execution systems. The methods defined by the Commands class will typically delegate to an instance of this class.

An execution system provider is a concrete implementation of this class that has a zero argument constructor. Providers are identified by their URI scheme. URI schemes are case-insensitive. The default provider is identified by the URI scheme "exec". It creates the ExecutionSystem that executes commands on the host running the Java Virtual Machine.

A provider is a factory for one or more ExecutionSystem instances. Each system is identified by a URI with a scheme that matches this provider's scheme. For example, the default execution system is identified by the URI exec:///. Other providers may define more complex URI schemes that include host information or query strings.

Providers are loaded using the standard service-loading functionality implemented by the ServiceLoader class. Providers are loaded using the system class loader. If the system class loader cannot be found then the extension class loader is used; if there is no extension class loader then the bootstrap class loader is used. Providers are typically installed by adding a JAR file to the application's classpath. The JAR file contains a configuration file named com.palantir.giraffe.command.spi.ExecutionSystemProvider in the resource directory META-INF/services. This file lists one or more fully qualified names of concrete implementations of this class. The order of loaded providers is implementation specific. If two providers have the same URI scheme the most recently loaded duplicate is discarded.

All of the methods in this class are safe for use by multiple threads.

Constructor Summary

Constructors

Constructor and Description
ExecutionSystemProvider()

Method Summary

Modifier and Type	Method and Description
abstract CommandFuture	execute(Command command, CommandContext context)
abstract ExecutionSystem	getExecutionSystem(URI uri)
static List<ExecutionSystemProvider>	installedProviders()
abstract ExecutionSystem	newExecutionSystem(URI uri, Map<String,?> env)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.palantir.giraffe.internal.SchemeIdentifiable

getScheme

Constructor Detail

ExecutionSystemProvider

public ExecutionSystemProvider()

Method Detail

installedProviders

public static List<ExecutionSystemProvider> installedProviders()

newExecutionSystem

public abstract ExecutionSystem newExecutionSystem(URI uri,
                                                   Map<String,?> env)
                                            throws IOException

Throws:

IOException

getExecutionSystem

public abstract ExecutionSystem getExecutionSystem(URI uri)

execute

public abstract CommandFuture execute(Command command,
                                      CommandContext context)