public interface ScriptEngineFactory
ScriptEngineFactory
is used to describe and instantiate ScriptEngines
.
Each class implementing ScriptEngine
has a corresponding factory that exposes metadata describing the engine class.
The ScriptEngineManager
uses the service provider mechanism described in the Jar File Specification to obtain instances of all ScriptEngineFactories
available in the current ClassLoader.
String getEngineName()
Returns the full name of the ScriptEngine
. For instance an implementation based on the Mozilla Rhino Javascript engine might return Rhino Mozilla Javascript Engine.
String getEngineVersion()
Returns the version of the ScriptEngine
.
ScriptEngine
implementation version.List<String> getExtensions()
Returns an immutable list of filename extensions, which generally identify scripts written in the language supported by this ScriptEngine
. The array is used by the ScriptEngineManager
to implement its getEngineByExtension
method.
List<String> getMimeTypes()
Returns an immutable list of mimetypes, associated with scripts that can be executed by the engine. The list is used by the ScriptEngineManager
class to implement its getEngineByMimetype
method.
List<String> getNames()
Returns an immutable list of short names for the ScriptEngine
, which may be used to identify the ScriptEngine
by the ScriptEngineManager
. For instance, an implementation based on the Mozilla Rhino Javascript engine might return list containing {"javascript", "rhino"}.
String getLanguageName()
Returns the name of the scripting language supported by this ScriptEngine
.
String getLanguageVersion()
Returns the version of the scripting language supported by this ScriptEngine
.
Object getParameter(String key)
Returns the value of an attribute whose meaning may be implementation-specific. Keys for which the value is defined in all implementations are:
The values for these keys are the Strings returned by getEngineName
, getEngineVersion
, getLanguageName
, getLanguageVersion
for the first four keys respectively. For NAME, one of the Strings returned by getNames
is returned.
A reserved key, THREADING
, whose value describes the behavior of the engine with respect to concurrent execution of scripts and maintenance of state is also defined. These values for the THREADING
key are:
null
- The engine implementation is not thread safe, and cannot be used to execute scripts concurrently on multiple threads. "MULTITHREADED"
- The engine implementation is internally thread-safe and scripts may execute concurrently although effects of script execution on one thread may be visible to scripts on other threads. "THREAD-ISOLATED"
- The implementation satisfies the requirements of "MULTITHREADED", and also, the engine maintains independent values for symbols in scripts executing on different threads. "STATELESS"
- The implementation satisfies the requirements of "THREAD-ISOLATED"
. In addition, script executions do not alter the mappings in the Bindings
which is the engine scope of the ScriptEngine
. In particular, the keys in the Bindings
and their associated values are the same before and after the execution of the script. key
- The name of the parameternull
if no value is assigned to the key.String getMethodCallSyntax(String obj, String m, String... args)
Returns a String which can be used to invoke a method of a Java object using the syntax of the supported scripting language. For instance, an implementation for a Javascript engine might be;
public String getMethodCallSyntax(String obj, String m, String... args) { String ret = obj; ret += "." + m + "("; for (int i = 0; i < args.length; i++) { ret += args[i]; if (i < args.length - 1) { ret += ","; } } ret += ")"; return ret; }
obj
- The name representing the object whose method is to be invoked. The name is the one used to create bindings using the put
method of ScriptEngine
, the put
method of an ENGINE_SCOPE
Bindings
,or the setAttribute
method of ScriptContext
. The identifier used in scripts may be a decorated form of the specified one.m
- The name of the method to invoke.args
- names of the arguments in the method call.String getOutputStatement(String toDisplay)
Returns a String that can be used as a statement to display the specified String using the syntax of the supported scripting language. For instance, the implementation for a Perl engine might be;
public String getOutputStatement(String toDisplay) { return "print(" + toDisplay + ")"; }
toDisplay
- The String to be displayed by the returned statement.String getProgram(String... statements)
Returns a valid scripting language executable program with given statements. For instance an implementation for a PHP engine might be:
public String getProgram(String... statements) { String retval = "<?\n"; int len = statements.length; for (int i = 0; i < len; i++) { retval += statements[i] + ";\n"; } return retval += "?>"; }
statements
- The statements to be executed. May be return values of calls to the getMethodCallSyntax
and getOutputStatement
methods.ScriptEngine getScriptEngine()
Returns an instance of the ScriptEngine
associated with this ScriptEngineFactory
. A new ScriptEngine is generally returned, but implementations may pool, share or reuse engines.
ScriptEngine
instance.
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.