Mercurial > 510Connectbot
comparison src/com/five_ten_sg/connectbot/service/PromptHelper.java @ 0:0ce5cc452d02
initial version
author | Carl Byington <carl@five-ten-sg.com> |
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date | Thu, 22 May 2014 10:41:19 -0700 |
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-1:000000000000 | 0:0ce5cc452d02 |
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1 /* | |
2 * ConnectBot: simple, powerful, open-source SSH client for Android | |
3 * Copyright 2007 Kenny Root, Jeffrey Sharkey | |
4 * | |
5 * Licensed under the Apache License, Version 2.0 (the "License"); | |
6 * you may not use this file except in compliance with the License. | |
7 * 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 | |
18 package com.five_ten_sg.connectbot.service; | |
19 | |
20 import java.util.concurrent.Semaphore; | |
21 | |
22 import android.os.Handler; | |
23 import android.os.Message; | |
24 | |
25 /** | |
26 * Helps provide a relay for prompts and responses between a possible user | |
27 * interface and some underlying service. | |
28 * | |
29 * @author jsharkey | |
30 */ | |
31 public class PromptHelper { | |
32 private final Object tag; | |
33 | |
34 private Handler handler = null; | |
35 | |
36 private Semaphore promptToken; | |
37 private Semaphore promptResponse; | |
38 | |
39 public String promptInstructions = null; | |
40 public String promptHint = null; | |
41 public Object promptRequested = null; | |
42 public boolean passwordRequested = true; | |
43 | |
44 private Object response = null; | |
45 | |
46 public PromptHelper(Object tag) { | |
47 this.tag = tag; | |
48 // Threads must acquire this before they can send a prompt. | |
49 promptToken = new Semaphore(1); | |
50 // Responses will release this semaphore. | |
51 promptResponse = new Semaphore(0); | |
52 } | |
53 | |
54 | |
55 /** | |
56 * Register a user interface handler, if available. | |
57 */ | |
58 public void setHandler(Handler handler) { | |
59 this.handler = handler; | |
60 } | |
61 | |
62 /** | |
63 * Set an incoming value from an above user interface. Will automatically | |
64 * notify any waiting requests. | |
65 */ | |
66 public void setResponse(Object value) { | |
67 response = value; | |
68 promptRequested = null; | |
69 promptInstructions = null; | |
70 promptHint = null; | |
71 promptResponse.release(); | |
72 } | |
73 | |
74 /** | |
75 * Return the internal response value just before erasing and returning it. | |
76 */ | |
77 protected Object popResponse() { | |
78 Object value = response; | |
79 response = null; | |
80 return value; | |
81 } | |
82 | |
83 | |
84 /** | |
85 * Request a prompt response from parent. This is a blocking call until user | |
86 * interface returns a value. | |
87 * Only one thread can call this at a time. cancelPrompt() will force this to | |
88 * immediately return. | |
89 */ | |
90 private Object requestPrompt(String instructions, String hint, Object type) throws InterruptedException { | |
91 Object response = null; | |
92 promptToken.acquire(); | |
93 | |
94 try { | |
95 promptInstructions = instructions; | |
96 promptHint = hint; | |
97 promptRequested = type; | |
98 | |
99 // notify any parent watching for live events | |
100 if (handler != null) | |
101 Message.obtain(handler, -1, tag).sendToTarget(); | |
102 | |
103 // acquire lock until user passes back value | |
104 promptResponse.acquire(); | |
105 response = popResponse(); | |
106 } | |
107 finally { | |
108 promptToken.release(); | |
109 } | |
110 | |
111 return response; | |
112 } | |
113 | |
114 /** | |
115 * Request a string response from parent. This is a blocking call until user | |
116 * interface returns a value. | |
117 * @param hint prompt hint for user to answer | |
118 * @return string user has entered | |
119 */ | |
120 public String requestStringPrompt(String instructions, String hint) { | |
121 String value = null; | |
122 passwordRequested = false; | |
123 | |
124 try { | |
125 value = (String)this.requestPrompt(instructions, hint, String.class); | |
126 } | |
127 catch (Exception e) { | |
128 } | |
129 | |
130 return value; | |
131 } | |
132 | |
133 /** | |
134 * Request a password response from parent. This is a blocking call until user | |
135 * interface returns a value. | |
136 * @param hint prompt hint for user to answer | |
137 * @return string user has entered | |
138 */ | |
139 public String requestPasswordPrompt(String instructions, String hint) { | |
140 String value = null; | |
141 passwordRequested = true; | |
142 | |
143 try { | |
144 value = (String)this.requestPrompt(instructions, hint, String.class); | |
145 } | |
146 catch (Exception e) { | |
147 } | |
148 | |
149 return value; | |
150 } | |
151 | |
152 /** | |
153 * Request a boolean response from parent. This is a blocking call until user | |
154 * interface returns a value. | |
155 * @param hint prompt hint for user to answer | |
156 * @return choice user has made (yes/no) | |
157 */ | |
158 public Boolean requestBooleanPrompt(String instructions, String hint) { | |
159 Boolean value = null; | |
160 | |
161 try { | |
162 value = (Boolean)this.requestPrompt(instructions, hint, Boolean.class); | |
163 } | |
164 catch (Exception e) { | |
165 } | |
166 | |
167 return value; | |
168 } | |
169 | |
170 /** | |
171 * Cancel an in-progress prompt. | |
172 */ | |
173 public void cancelPrompt() { | |
174 if (!promptToken.tryAcquire()) { | |
175 // A thread has the token, so try to interrupt it | |
176 response = null; | |
177 promptResponse.release(); | |
178 } | |
179 else { | |
180 // No threads have acquired the token | |
181 promptToken.release(); | |
182 } | |
183 } | |
184 } |