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
26package javax.script;
27
28import 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 */
44public 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}
118