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 *
37 * @author Robert Field
38 * @since 9
39 */
40public interface ExecutionControlProvider {
41
42    /**
43     * The unique name of this {@code ExecutionControlProvider}.  The name must
44     * be a sequence of characters from the Basic Multilingual Plane which are
45     * {@link Character#isJavaIdentifierPart(char) }.
46     *
47     * @return the ExecutionControlProvider's name
48     */
49    String name();
50
51    /**
52     * Create and return the default parameter map for this
53     * {@code ExecutionControlProvider}. The map can optionally be modified;
54     * Modified or unmodified it can be passed to
55     * {@link #generate(jdk.jshell.spi.ExecutionEnv, java.util.Map) }.
56     *
57     * @return the default parameter map
58     */
59    default Map<String,String> defaultParameters() {
60        return Collections.emptyMap();
61    }
62
63    /**
64     * Create and return the {@code ExecutionControl} instance.
65     *
66     * @param env the execution environment, provided by JShell
67     * @param parameters the {@linkplain #defaultParameters() default} or
68     * modified parameter map.
69     * @return the execution engine
70     * @throws Throwable an exception that occurred attempting to create the
71     * execution engine.
72     */
73    ExecutionControl generate(ExecutionEnv env, Map<String,String> parameters)
74            throws Throwable;
75}
76