ExecutionControlProvider.java revision 3846:605b0823d19b 
1/*
2 * Copyright (c) 2016, 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 jdk.jshell.spi;
27
28import java.util.Collections;
29import java.util.Map;
30
31/**
32 * The provider used by JShell to generate the execution engine needed to
33 * evaluate Snippets.  Alternate execution engines can be created by
34 * implementing this interface, then configuring JShell with the provider or
35 * the providers name and parameter specifier.
36 * @author Robert Field
37 */
38public interface ExecutionControlProvider {
39
40    /**
41     * The unique name of this {@code ExecutionControlProvider}.  The name must
42     * be a sequence of characters from the Basic Multilingual Plane which are
43     * {@link Character#isJavaIdentifierPart(char) }.
44     *
45     * @return the ExecutionControlProvider's name
46     */
47    String name();
48
49    /**
50     * Create and return the default parameter map for this
51     * {@code ExecutionControlProvider}. The map can optionally be modified;
52     * Modified or unmodified it can be passed to
53     * {@link #generate(jdk.jshell.spi.ExecutionEnv, java.util.Map) }.
54     *
55     * @return the default parameter map
56     */
57    default Map<String,String> defaultParameters() {
58        return Collections.emptyMap();
59    }
60
61    /**
62     * Create and return the {@code ExecutionControl} instance.
63     *
64     * @param env the execution environment, provided by JShell
65     * @param parameters the {@linkplain #defaultParameters() default} or
66     * modified parameter map.
67     * @return the execution engine
68     * @throws Throwable an exception that occurred attempting to create the
69     * execution engine.
70     */
71    ExecutionControl generate(ExecutionEnv env, Map<String,String> parameters)
72            throws Throwable;
73}
74