src/java.scripting/share/classes/javax/script/ScriptEngineFactory.java
changeset 47216 71c04702a3d5
parent 41587 47e38af37938
child 47750 0084b493dfc9
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.scripting/share/classes/javax/script/ScriptEngineFactory.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2005, 2016, 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.List;
+
+/**
+ * <code>ScriptEngineFactory</code> is used to describe and instantiate
+ * <code>ScriptEngines</code>.
+ * <br><br>
+ * Each class implementing <code>ScriptEngine</code> has a corresponding
+ * factory that exposes metadata describing the engine class.
+ * <br><br>The <code>ScriptEngineManager</code>
+ * uses the service-provider loader mechanism described in the
+ * {@link java.util.ServiceLoader} class to obtain
+ * instances of {@code ScriptEngineFactory} instances.
+ * See {@link ScriptEngineManager#ScriptEngineManager()} and
+ * {@link ScriptEngineManager#ScriptEngineManager(java.lang.ClassLoader)}.
+ *
+ * @since 1.6
+ */
+public interface ScriptEngineFactory {
+    /**
+     * Returns the full  name of the <code>ScriptEngine</code>.  For
+     * instance an implementation based on the Mozilla Rhino Javascript engine
+     * might return <i>Rhino Mozilla Javascript Engine</i>.
+     * @return The name of the engine implementation.
+     */
+    public String getEngineName();
+
+    /**
+     * Returns the version of the <code>ScriptEngine</code>.
+     * @return The <code>ScriptEngine</code> implementation version.
+     */
+    public String getEngineVersion();
+
+
+    /**
+     * Returns an immutable list of filename extensions, which generally identify scripts
+     * written in the language supported by this <code>ScriptEngine</code>.
+     * The array is used by the <code>ScriptEngineManager</code> to implement its
+     * <code>getEngineByExtension</code> method.
+     * @return The list of extensions.
+     */
+    public List<String> getExtensions();
+
+
+    /**
+     * Returns an immutable list of mimetypes, associated with scripts that
+     * can be executed by the engine.  The list is used by the
+     * <code>ScriptEngineManager</code> class to implement its
+     * <code>getEngineByMimetype</code> method.
+     * @return The list of mime types.
+     */
+    public List<String> getMimeTypes();
+
+    /**
+     * Returns an immutable list of  short names for the <code>ScriptEngine</code>, which may be used to
+     * identify the <code>ScriptEngine</code> by the <code>ScriptEngineManager</code>.
+     * For instance, an implementation based on the Mozilla Rhino Javascript engine might
+     * return list containing {&quot;javascript&quot;, &quot;rhino&quot;}.
+     * @return an immutable list of short names
+     */
+    public List<String> getNames();
+
+    /**
+     * Returns the name of the scripting language supported by this
+     * <code>ScriptEngine</code>.
+     * @return The name of the supported language.
+     */
+    public String getLanguageName();
+
+    /**
+     * Returns the version of the scripting language supported by this
+     * <code>ScriptEngine</code>.
+     * @return The version of the supported language.
+     */
+    public String getLanguageVersion();
+
+    /**
+     * Returns the value of an attribute whose meaning may be implementation-specific.
+     * Keys for which the value is defined in all implementations are:
+     * <ul>
+     * <li>ScriptEngine.ENGINE</li>
+     * <li>ScriptEngine.ENGINE_VERSION</li>
+     * <li>ScriptEngine.LANGUAGE</li>
+     * <li>ScriptEngine.LANGUAGE_VERSION</li>
+     * <li>ScriptEngine.NAME</li>
+     * </ul>
+     * <p>
+     * The values for these keys are the Strings returned by <code>getEngineName</code>,
+     * <code>getEngineVersion</code>, <code>getLanguageName</code>,
+     * <code>getLanguageVersion</code> for the first four keys respectively. For NAME, one of the Strings
+     * returned by <code>getNames</code> is returned.<br><br>
+     * A reserved key, <code><b>THREADING</b></code>, 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 <code><b>THREADING</b></code> key are:<br><br>
+     * <ul>
+     * <li><code>null</code> - The engine implementation is not thread safe, and cannot
+     * be used to execute scripts concurrently on multiple threads.
+     * <li><code>&quot;MULTITHREADED&quot;</code> - 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.
+     * <li><code>&quot;THREAD-ISOLATED&quot;</code> - The implementation satisfies the requirements
+     * of &quot;MULTITHREADED&quot;, and also, the engine maintains independent values
+     * for symbols in scripts executing on different threads.
+     * <li><code>&quot;STATELESS&quot;</code> - The implementation satisfies the requirements of
+     * <code>&quot;THREAD-ISOLATED&quot;</code>.  In addition, script executions do not alter the
+     * mappings in the <code>Bindings</code> which is the engine scope of the
+     * <code>ScriptEngine</code>.  In particular, the keys in the <code>Bindings</code>
+     * and their associated values are the same before and after the execution of the script.
+     * </ul>
+     * <br><br>
+     * Implementations may define implementation-specific keys.
+     *
+     * @param key The name of the parameter
+     * @return The value for the given parameter. Returns <code>null</code> if no
+     * value is assigned to the key.
+     *
+     * @throws NullPointerException if the key is null.
+     */
+    public Object getParameter(String key);
+
+    /**
+     * 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;
+     *
+     * <pre>{@code
+     * 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;
+     * }
+     * } </pre>
+     *
+     * @param obj The name representing the object whose method is to be invoked. The
+     * name is the one used to create bindings using the <code>put</code> method of
+     * <code>ScriptEngine</code>, the <code>put</code> method of an <code>ENGINE_SCOPE</code>
+     * <code>Bindings</code>,or the <code>setAttribute</code> method
+     * of <code>ScriptContext</code>.  The identifier used in scripts may be a decorated form of the
+     * specified one.
+     *
+     * @param m The name of the method to invoke.
+     * @param args names of the arguments in the method call.
+     *
+     * @return The String used to invoke the method in the syntax of the scripting language.
+     */
+    public String getMethodCallSyntax(String obj, String m, String... args);
+
+    /**
+     * 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;
+     *
+     * <pre><code>
+     * public String getOutputStatement(String toDisplay) {
+     *      return "print(" + toDisplay + ")";
+     * }
+     * </code></pre>
+     *
+     * @param toDisplay The String to be displayed by the returned statement.
+     * @return The string used to display the String in the syntax of the scripting language.
+     *
+     *
+     */
+    public String getOutputStatement(String toDisplay);
+
+
+    /**
+     * Returns a valid scripting language executable program with given statements.
+     * For instance an implementation for a PHP engine might be:
+     *
+     * <pre>{@code
+     * 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 += "?>";
+     * }
+     * }</pre>
+     *
+     *  @param statements The statements to be executed.  May be return values of
+     *  calls to the <code>getMethodCallSyntax</code> and <code>getOutputStatement</code> methods.
+     *  @return The Program
+     *
+     *  @throws NullPointerException if the <code>statements</code> array or any of its elements is null
+     */
+    public String getProgram(String... statements);
+
+    /**
+     * Returns an instance of the <code>ScriptEngine</code> associated with this
+     * <code>ScriptEngineFactory</code>. A new ScriptEngine is generally
+     * returned, but implementations may pool, share or reuse engines.
+     *
+     * @return A new <code>ScriptEngine</code> instance.
+     */
+    public  ScriptEngine getScriptEngine();
+}