1 /*

     2  * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package javax.script;

    27 

    28 import java.util.Map;

    29 

    30 /**

    31  * Extended by classes that store results of compilations.  State

    32  * might be stored in the form of Java classes, Java class files or scripting

    33  * language opcodes.  The script may be executed repeatedly

    34  * without reparsing.

    35  * <br><br>

    36  * Each <code>CompiledScript</code> is associated with a <code>ScriptEngine</code> -- A call to an  <code>eval</code>

    37  * method of the <code>CompiledScript</code> causes the execution of the script by the

    38  * <code>ScriptEngine</code>.  Changes in the state of the <code>ScriptEngine</code> caused by execution

    39  * of the <code>CompiledScript</code>  may visible during subsequent executions of scripts by the engine.

    40  *

    41  * @author Mike Grogan

    42  * @since 1.6

    43  */

    44 public abstract class CompiledScript {

    45 

    46     /**

    47      * Executes the program stored in this <code>CompiledScript</code> object.

    48      *

    49      * @param context A <code>ScriptContext</code> that is used in the same way as

    50      * the <code>ScriptContext</code> passed to the <code>eval</code> methods of

    51      * <code>ScriptEngine</code>.

    52      *

    53      * @return The value returned by the script execution, if any.  Should return <code>null</code>

    54      * if no value is returned by the script execution.

    55      *

    56      * @throws ScriptException if an error occurs.

    57      * @throws NullPointerException if context is null.

    58      */

    59 

    60     public abstract Object eval(ScriptContext context) throws ScriptException;

    61 

    62     /**

    63      * Executes the program stored in the <code>CompiledScript</code> object using

    64      * the supplied <code>Bindings</code> of attributes as the <code>ENGINE_SCOPE</code> of the

    65      * associated <code>ScriptEngine</code> during script execution.  If bindings is null,

    66      * then the effect of calling this method is same as that of eval(getEngine().getContext()).

    67      * <p>.

    68      * The <code>GLOBAL_SCOPE</code> <code>Bindings</code>, <code>Reader</code> and <code>Writer</code>

    69      * associated with the default <code>ScriptContext</code> of the associated <code>ScriptEngine</code> are used.

    70      *

    71      * @param bindings The bindings of attributes used for the <code>ENGINE_SCOPE</code>.

    72      *

    73      * @return The return value from the script execution

    74      *

    75      * @throws ScriptException if an error occurs.

    76      */

    77     public Object eval(Bindings bindings) throws ScriptException {

    78 

    79         ScriptContext ctxt = getEngine().getContext();

    80 

    81         if (bindings != null) {

    82             SimpleScriptContext tempctxt = new SimpleScriptContext();

    83             tempctxt.setBindings(bindings, ScriptContext.ENGINE_SCOPE);

    84             tempctxt.setBindings(ctxt.getBindings(ScriptContext.GLOBAL_SCOPE),

    85                     ScriptContext.GLOBAL_SCOPE);

    86             tempctxt.setWriter(ctxt.getWriter());

    87             tempctxt.setReader(ctxt.getReader());

    88             tempctxt.setErrorWriter(ctxt.getErrorWriter());

    89             ctxt = tempctxt;

    90         }

    91 

    92         return eval(ctxt);

    93     }

    94 

    95 

    96     /**

    97      * Executes the program stored in the <code>CompiledScript</code> object.  The

    98      * default <code>ScriptContext</code> of the associated <code>ScriptEngine</code> is used.

    99      * The effect of calling this method is same as that of eval(getEngine().getContext()).

   100      *

   101      * @return The return value from the script execution

   102      *

   103      * @throws ScriptException if an error occurs.

   104      */

   105     public Object eval() throws ScriptException {

   106         return eval(getEngine().getContext());

   107     }

   108 

   109     /**

   110      * Returns the <code>ScriptEngine</code> whose <code>compile</code> method created this <code>CompiledScript</code>.

   111      * The <code>CompiledScript</code> will execute in this engine.

   112      *

   113      * @return The <code>ScriptEngine</code> that created this <code>CompiledScript</code>

   114      */

   115     public abstract ScriptEngine getEngine();

   116 

   117 }