1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.scxml2.env.minimal;
18
19 import java.util.Collections;
20 import java.util.Map;
21
22 import org.apache.commons.scxml2.Context;
23 import org.apache.commons.scxml2.env.SimpleContext;
24
25 /**
26 * MinimalContext implementation for the SCXML Null Data Model.
27 * <p>
28 * This context disables any access to the parent context (other than through getParent()) and
29 * ignores setting any local data.
30 * </p>
31 * <p>
32 * The MinimalContext requires a none MinimalContext based parent Context for creation.
33 * If the parent context is of type MinimalContext, <em>its</em> parent will be used as the parent of the
34 * new MinimalContext instance
35 * </p>
36 */
37 public class MinimalContext extends SimpleContext {
38
39 /** Serial version UID. */
40 private static final long serialVersionUID = 1L;
41
42 private static Context getMinimalContextParent(final Context parent) {
43 if (parent != null) {
44 if (parent instanceof MinimalContext) {
45 return getMinimalContextParent(parent.getParent());
46 }
47 return parent;
48 }
49 throw new IllegalStateException("A MinimalContext instance requires a non MinimalContext based parent.");
50 }
51
52 public MinimalContext(final Context parent) {
53 super(getMinimalContextParent(parent));
54 }
55
56 @Override
57 public void set(final String name, final Object value) {
58 }
59
60 @Override
61 public Object get(final String name) {
62 return null;
63 }
64
65 @Override
66 public boolean has(final String name) {
67 return false;
68 }
69
70 @Override
71 public boolean hasLocal(final String name) {
72 return false;
73 }
74
75 @Override
76 public void reset() {
77 }
78
79 @Override
80 public void setLocal(final String name, final Object value) {
81 }
82
83 @Override
84 protected void setVars(final Map<String, Object> vars) {
85 }
86
87 @Override
88 public Map<String, Object> getVars() {
89 return Collections.emptyMap();
90 }
91 }