javax.script.ScriptEngineManager Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package javax.script;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import javax.imageio.spi.ServiceRegistry;
/**
* See Javadoc of Java Scripting API
*/
public class ScriptEngineManager {
/**
* Stores all instances of classes which implement
* ScriptEngineFactory which are found in resources
* META-INF/services/javax.script.ScriptEngineFactory
*/
private final HashSet engineSpis = new HashSet();
/**
* Maps language names to the associated ScriptEngineFactory
*/
private final HashMap nameAssociations = new HashMap();
/**
* Maps file extensions to the associated ScriptEngineFactory
*/
private final HashMap extensionAssociations = new HashMap();
/** Maps MIME types to the associated ScriptEngineFactory */
private final HashMap mimeTypeAssociations = new HashMap();
/** Stores the bindings associated with GLOBAL_SCOPE. Defaults to SimpleBindings. */
private Bindings globalscope = new SimpleBindings();
/**
* Constructs a ScriptEngineManager and
* initializes it using the current context classloader.
*/
public ScriptEngineManager() {
this(Thread.currentThread().getContextClassLoader());
}
/**
* Constructs a ScriptEngineManager and
* initializes it using the specified classloader.
*
* @param loader the classloader to use (may be null)
*/
public ScriptEngineManager(ClassLoader loader) {
Iterator iterator = ServiceRegistry.lookupProviders(ScriptEngineFactory.class, loader);
while (iterator.hasNext()) {
ScriptEngineFactory factory;
try {
factory = (ScriptEngineFactory) iterator.next();
} catch (ThreadDeath td) { // must not ignore this
throw td;
// See BSF-30 - iterator may throw Error
} catch (Error ignored) {
continue;
}
engineSpis.add(factory);
List data = factory.getNames();
// gets all descriptive names for Scripting Engine
for (int i=0; inull if no
* suitable ScriptingEngine is found.
*
* @param extension the specified extension of a script file
* @return a new instance of a ScriptingEngine which supports the
* specified script file extension
*
* @throws NullPointerException if extension is null
*/
public ScriptEngine getEngineByExtension(String extension){
if (extension == null) {
throw new NullPointerException("extension must not be null");
}
ScriptEngine engine = null;
ScriptEngineFactory factory =
(ScriptEngineFactory) extensionAssociations.get(extension);
if (factory != null) {
// gets a new instance of the Scripting Engine
engine = factory.getScriptEngine();
// sets the GLOBAL SCOPE
engine.setBindings(globalscope,ScriptContext.GLOBAL_SCOPE);
}
return engine;
}
/**
* Retrieves new instance the ScriptingEngine for a specifed MIME
* type. Returns null if no suitable ScriptingEngine is found.
*
* @param mimeType the specified MIME type
* @return a new instance of a ScriptingEngine which supports the
* specified MIME type
*
* @throws NullPointerException if mimeType is null
*/
public ScriptEngine getEngineByMimeType(String mimeType){
if (mimeType == null) {
throw new NullPointerException("mimeType must not be null");
}
ScriptEngine engine = null;
ScriptEngineFactory factory =
(ScriptEngineFactory) mimeTypeAssociations.get(mimeType);
if (factory != null) {
// gets a new instance of the Scripting Engine
engine = factory.getScriptEngine();
// sets the GLOBAL SCOPE
engine.setBindings(globalscope,ScriptContext.GLOBAL_SCOPE);
}
return engine;
}
/**
* Retrieves a new instance of a ScriptEngine the specified
* descriptive name. Returns null if no suitable ScriptEngine is
* found.
*
* @param shortName the short name of the engine
* @return a new instance of a ScriptEngine which supports the
* specifed name
* @throws NullPointerException - if shortName is null
*/
public ScriptEngine getEngineByName(String shortName){
if (shortName == null) {
throw new NullPointerException("shortName must not be null");
}
ScriptEngine engine = null;
ScriptEngineFactory factory =
(ScriptEngineFactory) nameAssociations.get(shortName);
if (factory != null) {
engine = factory.getScriptEngine();
engine.setBindings(globalscope,ScriptContext.GLOBAL_SCOPE);
}
return engine;
}
/**
* Retrieves an array of instances of ScriptEngineFactory class
* which are found by the discovery mechanism.
*
* @return a list of all discovered ScriptEngineFactory
* instances
*/
public List getEngineFactories(){
ArrayList factories = new ArrayList();
Iterator iter = engineSpis.iterator();
while(iter.hasNext()) {
factories.add(iter.next());
}
return factories;
}
/**
* Retrieves the bindings corresponds to GLOBAL_SCOPE.
*
* @return the bindings of GLOBAL_SCOPE
*/
public Bindings getBindings(){
return globalscope;
}
/**
* Associates the specifed value with the specified key in
* GLOBAL_SCOPE.
*
* @param key the associated key for specified value
* @param value the associated value for the specified key
*
* @throws NullPointerException if key is null
* @throws IllegalArgumentException if key is the empty String
*/
public void put(String key, Object value){
if (key == null) {
throw new NullPointerException("key must not be null");
}
if (key.length() == 0) {
throw new IllegalArgumentException("key must not be the empty string");
}
globalscope.put(key, value);
}
/**
* Register a extension with a ScriptEngineFactory. It
* overrides any such association discovered previously.
*
* @param extension the extension associated with the specified
* ScriptEngineFactory class
* @param factory the ScriptEngineFactory associated with
* the specified extension
*
* @throws NullPointerException if any of the parameters is null
*/
public void registerEngineExtension(String extension, ScriptEngineFactory factory){
if (extension == null || factory == null) {
throw new NullPointerException("parameters must be non-null");
}
extensionAssociations.put(extension, factory);
}
/**
* Registers descriptive name with a ScriptEngineFactory.
* It overrides any associations discovered previously.
*
* @param name a descriptive name associated with the specifed
* ScriptEngineFactory class
* @param factory the ScriptEngineFactory associated with
* the specified descriptive name
*
* @throws NullPointerException if any of the parameters is null
*/
public void registerEngineName(String name, ScriptEngineFactory factory){
if (name == null || factory == null) {
throw new NullPointerException("parameters must be non-null");
}
nameAssociations.put(name, factory);
}
/**
* Registers a MIME type with a ScriptEngineFactory. It
* overrides any associations discovered previously.
*
* @param mimeType the MIME type associated with specified
* ScriptEngineFactory class
* @param factory the ScriptEngineFactory associated with the
* specified MIME type
*
* @throws NullPointerException if any of the parameters is null
*/
public void registerEngineMimeType(String mimeType,ScriptEngineFactory factory){
if (mimeType == null || factory == null) {
throw new NullPointerException("parameters must be non-null");
}
mimeTypeAssociations.put(mimeType,factory);
}
/**
* Sets the GLOBAL_SCOPE value to the specified bindings.
*
* @param bindings the bindings to be stored in GLOBAL_SCOPE
* @throws IllegalArgumentException if bindings is null
*/
public void setBindings(Bindings bindings){
if (bindings == null){
throw new IllegalArgumentException("bindings must not be null");
}
globalscope = bindings;
}
}