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Defines the Service Provider Interface for pluggable JShell execution engines. The JShell core tracks and compiles Snippets then sends them (represented in a wrapper class) to the execution engine for loading, and in the case of executable Snippets, execution. The JShell implementation includes a default execution engine (currently a remote process which is JDI controlled). By implementing the ExecutionControl interface and its generating class, an implementation of the ExecutionControlProvider interface, and installing it with Builder.executionEngine(String) other execution engines can be used. Where the passed String is an ExecutionControl spec. 
 The ExecutionControl spec is the ExecutionControlProvider name optionally followed by a parameter specification. The syntax of the spec is: 
spec   := name : params
       | name
name   := identifier
params := param , params
       | param
       |
param  := identifier ( value )
 Where 'name' is the ExecutionControlProvider name. Where 'param' is a Map key from ExecutionControlProvider.defaultParameters() and the parenthesized value; See, for example, JdiExecutionControlProvider. Where 'identifier' is a sequence of 
Java identifier part characters from the Basic Multilingual Plane. 

For example:

  
local
  
jdi:hostname(localhost)
  
failover:1(jdi),2(jdi:launch(true),timeout(3000)),3(local)

See Also:
for execution implementation support
Since:
9/**
 * Defines the Service Provider Interface for pluggable JShell execution engines.
 * The JShell core tracks and compiles Snippets then sends them
 * (represented in a wrapper class) to the execution engine for loading,
 * and in the case of executable Snippets, execution.  The JShell
 * implementation includes a default execution engine (currently a remote
 * process which is JDI controlled).  By implementing the
 * {@link jdk.jshell.spi.ExecutionControl} interface and its generating class,
 * an implementation of the {@link jdk.jshell.spi.ExecutionControlProvider}
 * interface, and installing it with
 * {@link jdk.jshell.JShell.Builder#executionEngine(String)}
 * other execution engines can be used. Where the passed String is an
 * {@code ExecutionControl} spec.
 * <p>
 * The {@code ExecutionControl} spec is the {@code ExecutionControlProvider}
 * name optionally followed by a parameter specification.
 * The syntax of the spec is:
 * <pre>
 * spec   := name : params
 *        | name
 * name   := identifier
 * params := param , params
 *        | param
 *        |
 * param  := identifier ( value )
 * </pre>
 * Where 'name' is the {@code ExecutionControlProvider}
 * {@linkplain ExecutionControlProvider#name() name}.
 * Where 'param' is a Map key from
 * {@link ExecutionControlProvider#defaultParameters()} and the parenthesized
 * value; See, for example,
 * {@link jdk.jshell.execution.JdiExecutionControlProvider}.
 * Where 'identifier' is a sequence of
 * {@linkplain java.lang.Character#isJavaIdentifierPart(char)
 * Java identifier part characters} from the Basic Multilingual Plane.
 * <p>
 * For example:
 * <ul>
 *   <li>local</li>
 *   <li>jdi:hostname(localhost)</li>
 *   <li>failover:1(jdi),2(jdi:launch(true),timeout(3000)),3(local)</li>
 * </ul>
 *
 * @since 9
 * @see jdk.jshell.execution for execution implementation support
 */
package jdk.jshell.spi;