| /* |
| * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.script; |
| import java.util.*; |
| import java.security.*; |
| import java.util.ServiceLoader; |
| import java.util.ServiceConfigurationError; |
| |
| /** |
| * The <code>ScriptEngineManager</code> implements a discovery and instantiation |
| * mechanism for <code>ScriptEngine</code> classes and also maintains a |
| * collection of key/value pairs storing state shared by all engines created |
| * by the Manager. This class uses the service provider mechanism described in the |
| * {@link java.util.ServiceLoader} class to enumerate all the |
| * implementations of <code>ScriptEngineFactory</code>. <br><br> |
| * The <code>ScriptEngineManager</code> provides a method to return a list of all these factories |
| * as well as utility methods which look up factories on the basis of language name, file extension |
| * and mime type. |
| * <p> |
| * The <code>Bindings</code> of key/value pairs, referred to as the "Global Scope" maintained |
| * by the manager is available to all instances of <code>ScriptEngine</code> created |
| * by the <code>ScriptEngineManager</code>. The values in the <code>Bindings</code> are |
| * generally exposed in all scripts. |
| * |
| * @author Mike Grogan |
| * @author A. Sundararajan |
| * @since 1.6 |
| */ |
| public class ScriptEngineManager { |
| private static final boolean DEBUG = false; |
| /** |
| * The effect of calling this constructor is the same as calling |
| * <code>ScriptEngineManager(Thread.currentThread().getContextClassLoader())</code>. |
| * |
| * @see java.lang.Thread#getContextClassLoader |
| */ |
| public ScriptEngineManager() { |
| ClassLoader ctxtLoader = Thread.currentThread().getContextClassLoader(); |
| init(ctxtLoader); |
| } |
| |
| /** |
| * This constructor loads the implementations of |
| * <code>ScriptEngineFactory</code> visible to the given |
| * <code>ClassLoader</code> using the service provider mechanism.<br><br> |
| * If loader is <code>null</code>, the script engine factories that are |
| * bundled with the platform are loaded. <br> |
| * |
| * @param loader ClassLoader used to discover script engine factories. |
| */ |
| public ScriptEngineManager(ClassLoader loader) { |
| init(loader); |
| } |
| |
| private void init(final ClassLoader loader) { |
| globalScope = new SimpleBindings(); |
| engineSpis = new HashSet<ScriptEngineFactory>(); |
| nameAssociations = new HashMap<String, ScriptEngineFactory>(); |
| extensionAssociations = new HashMap<String, ScriptEngineFactory>(); |
| mimeTypeAssociations = new HashMap<String, ScriptEngineFactory>(); |
| initEngines(loader); |
| } |
| |
| private ServiceLoader<ScriptEngineFactory> getServiceLoader(final ClassLoader loader) { |
| if (loader != null) { |
| return ServiceLoader.load(ScriptEngineFactory.class, loader); |
| } else { |
| return ServiceLoader.loadInstalled(ScriptEngineFactory.class); |
| } |
| } |
| |
| private void initEngines(final ClassLoader loader) { |
| Iterator<ScriptEngineFactory> itr = null; |
| try { |
| ServiceLoader<ScriptEngineFactory> sl = AccessController.doPrivileged( |
| new PrivilegedAction<ServiceLoader<ScriptEngineFactory>>() { |
| @Override |
| public ServiceLoader<ScriptEngineFactory> run() { |
| return getServiceLoader(loader); |
| } |
| }); |
| |
| itr = sl.iterator(); |
| } catch (ServiceConfigurationError err) { |
| System.err.println("Can't find ScriptEngineFactory providers: " + |
| err.getMessage()); |
| if (DEBUG) { |
| err.printStackTrace(); |
| } |
| // do not throw any exception here. user may want to |
| // manage his/her own factories using this manager |
| // by explicit registratation (by registerXXX) methods. |
| return; |
| } |
| |
| try { |
| while (itr.hasNext()) { |
| try { |
| ScriptEngineFactory fact = itr.next(); |
| engineSpis.add(fact); |
| } catch (ServiceConfigurationError err) { |
| System.err.println("ScriptEngineManager providers.next(): " |
| + err.getMessage()); |
| if (DEBUG) { |
| err.printStackTrace(); |
| } |
| // one factory failed, but check other factories... |
| continue; |
| } |
| } |
| } catch (ServiceConfigurationError err) { |
| System.err.println("ScriptEngineManager providers.hasNext(): " |
| + err.getMessage()); |
| if (DEBUG) { |
| err.printStackTrace(); |
| } |
| // do not throw any exception here. user may want to |
| // manage his/her own factories using this manager |
| // by explicit registratation (by registerXXX) methods. |
| return; |
| } |
| } |
| |
| /** |
| * <code>setBindings</code> stores the specified <code>Bindings</code> |
| * in the <code>globalScope</code> field. ScriptEngineManager sets this |
| * <code>Bindings</code> as global bindings for <code>ScriptEngine</code> |
| * objects created by it. |
| * |
| * @param bindings The specified <code>Bindings</code> |
| * @throws IllegalArgumentException if bindings is null. |
| */ |
| public void setBindings(Bindings bindings) { |
| if (bindings == null) { |
| throw new IllegalArgumentException("Global scope cannot be null."); |
| } |
| |
| globalScope = bindings; |
| } |
| |
| /** |
| * <code>getBindings</code> returns the value of the <code>globalScope</code> field. |
| * ScriptEngineManager sets this <code>Bindings</code> as global bindings for |
| * <code>ScriptEngine</code> objects created by it. |
| * |
| * @return The globalScope field. |
| */ |
| public Bindings getBindings() { |
| return globalScope; |
| } |
| |
| /** |
| * Sets the specified key/value pair in the Global Scope. |
| * @param key Key to set |
| * @param value Value to set. |
| * @throws NullPointerException if key is null. |
| * @throws IllegalArgumentException if key is empty string. |
| */ |
| public void put(String key, Object value) { |
| globalScope.put(key, value); |
| } |
| |
| /** |
| * Gets the value for the specified key in the Global Scope |
| * @param key The key whose value is to be returned. |
| * @return The value for the specified key. |
| */ |
| public Object get(String key) { |
| return globalScope.get(key); |
| } |
| |
| /** |
| * Looks up and creates a <code>ScriptEngine</code> for a given name. |
| * The algorithm first searches for a <code>ScriptEngineFactory</code> that has been |
| * registered as a handler for the specified name using the <code>registerEngineName</code> |
| * method. |
| * <br><br> If one is not found, it searches the set of <code>ScriptEngineFactory</code> instances |
| * stored by the constructor for one with the specified name. If a <code>ScriptEngineFactory</code> |
| * is found by either method, it is used to create instance of <code>ScriptEngine</code>. |
| * @param shortName The short name of the <code>ScriptEngine</code> implementation. |
| * returned by the <code>getNames</code> method of its <code>ScriptEngineFactory</code>. |
| * @return A <code>ScriptEngine</code> created by the factory located in the search. Returns null |
| * if no such factory was found. The <code>ScriptEngineManager</code> sets its own <code>globalScope</code> |
| * <code>Bindings</code> as the <code>GLOBAL_SCOPE</code> <code>Bindings</code> of the newly |
| * created <code>ScriptEngine</code>. |
| * @throws NullPointerException if shortName is null. |
| */ |
| public ScriptEngine getEngineByName(String shortName) { |
| if (shortName == null) throw new NullPointerException(); |
| //look for registered name first |
| Object obj; |
| if (null != (obj = nameAssociations.get(shortName))) { |
| ScriptEngineFactory spi = (ScriptEngineFactory)obj; |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| |
| for (ScriptEngineFactory spi : engineSpis) { |
| List<String> names = null; |
| try { |
| names = spi.getNames(); |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| |
| if (names != null) { |
| for (String name : names) { |
| if (shortName.equals(name)) { |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| } |
| } |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Look up and create a <code>ScriptEngine</code> for a given extension. The algorithm |
| * used by <code>getEngineByName</code> is used except that the search starts |
| * by looking for a <code>ScriptEngineFactory</code> registered to handle the |
| * given extension using <code>registerEngineExtension</code>. |
| * @param extension The given extension |
| * @return The engine to handle scripts with this extension. Returns <code>null</code> |
| * if not found. |
| * @throws NullPointerException if extension is null. |
| */ |
| public ScriptEngine getEngineByExtension(String extension) { |
| if (extension == null) throw new NullPointerException(); |
| //look for registered extension first |
| Object obj; |
| if (null != (obj = extensionAssociations.get(extension))) { |
| ScriptEngineFactory spi = (ScriptEngineFactory)obj; |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| |
| for (ScriptEngineFactory spi : engineSpis) { |
| List<String> exts = null; |
| try { |
| exts = spi.getExtensions(); |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| if (exts == null) continue; |
| for (String ext : exts) { |
| if (extension.equals(ext)) { |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Look up and create a <code>ScriptEngine</code> for a given mime type. The algorithm |
| * used by <code>getEngineByName</code> is used except that the search starts |
| * by looking for a <code>ScriptEngineFactory</code> registered to handle the |
| * given mime type using <code>registerEngineMimeType</code>. |
| * @param mimeType The given mime type |
| * @return The engine to handle scripts with this mime type. Returns <code>null</code> |
| * if not found. |
| * @throws NullPointerException if mimeType is null. |
| */ |
| public ScriptEngine getEngineByMimeType(String mimeType) { |
| if (mimeType == null) throw new NullPointerException(); |
| //look for registered types first |
| Object obj; |
| if (null != (obj = mimeTypeAssociations.get(mimeType))) { |
| ScriptEngineFactory spi = (ScriptEngineFactory)obj; |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| |
| for (ScriptEngineFactory spi : engineSpis) { |
| List<String> types = null; |
| try { |
| types = spi.getMimeTypes(); |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| if (types == null) continue; |
| for (String type : types) { |
| if (mimeType.equals(type)) { |
| try { |
| ScriptEngine engine = spi.getScriptEngine(); |
| engine.setBindings(getBindings(), ScriptContext.GLOBAL_SCOPE); |
| return engine; |
| } catch (Exception exp) { |
| if (DEBUG) exp.printStackTrace(); |
| } |
| } |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Returns a list whose elements are instances of all the <code>ScriptEngineFactory</code> classes |
| * found by the discovery mechanism. |
| * @return List of all discovered <code>ScriptEngineFactory</code>s. |
| */ |
| public List<ScriptEngineFactory> getEngineFactories() { |
| List<ScriptEngineFactory> res = new ArrayList<ScriptEngineFactory>(engineSpis.size()); |
| for (ScriptEngineFactory spi : engineSpis) { |
| res.add(spi); |
| } |
| return Collections.unmodifiableList(res); |
| } |
| |
| /** |
| * Registers a <code>ScriptEngineFactory</code> to handle a language |
| * name. Overrides any such association found using the Discovery mechanism. |
| * @param name The name to be associated with the <code>ScriptEngineFactory</code>. |
| * @param factory The class to associate with the given 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(); |
| nameAssociations.put(name, factory); |
| } |
| |
| /** |
| * Registers a <code>ScriptEngineFactory</code> to handle a mime type. |
| * Overrides any such association found using the Discovery mechanism. |
| * |
| * @param type The mime type to be associated with the |
| * <code>ScriptEngineFactory</code>. |
| * |
| * @param factory The class to associate with the given mime type. |
| * @throws NullPointerException if any of the parameters is null. |
| */ |
| public void registerEngineMimeType(String type, ScriptEngineFactory factory) { |
| if (type == null || factory == null) throw new NullPointerException(); |
| mimeTypeAssociations.put(type, factory); |
| } |
| |
| /** |
| * Registers a <code>ScriptEngineFactory</code> to handle an extension. |
| * Overrides any such association found using the Discovery mechanism. |
| * |
| * @param extension The extension type to be associated with the |
| * <code>ScriptEngineFactory</code>. |
| * @param factory The class to associate with the given 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(); |
| extensionAssociations.put(extension, factory); |
| } |
| |
| /** Set of script engine factories discovered. */ |
| private HashSet<ScriptEngineFactory> engineSpis; |
| |
| /** Map of engine name to script engine factory. */ |
| private HashMap<String, ScriptEngineFactory> nameAssociations; |
| |
| /** Map of script file extension to script engine factory. */ |
| private HashMap<String, ScriptEngineFactory> extensionAssociations; |
| |
| /** Map of script MIME type to script engine factory. */ |
| private HashMap<String, ScriptEngineFactory> mimeTypeAssociations; |
| |
| /** Global bindings associated with script engines created by this manager. */ |
| private Bindings globalScope; |
| } |