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1
3 package org.jgroups.protocols;
4
5
6 import bsh.EvalError;
7 import bsh.Interpreter;
8 import org.jgroups.Address;
9 import org.jgroups.Event;
10 import org.jgroups.Header;
11 import org.jgroups.Message;
12 import org.jgroups.stack.Protocol;
13 import org.jgroups.util.Util;
14
15 import java.io.IOException  ;
16 import java.io.ObjectInput ;
17 import java.io.ObjectOutput ;
18 import java.io.Serializable ;
19
20
21
22
23
32 public class BSH extends Protocol {
33 static final String name="BSH";
34 Interpreter interpreter=null;
35
36 public BSH() {
37 ;
38 }
39
40 public String getName() {
41 return name;
42 }
43
44
45
46 public void init() throws Exception {
47 ;
48 }
49
50 public void start() throws Exception {
51 ;
52 }
53
54 public void stop() {
55 if(interpreter != null)
56 destroyInterpreter();
57 }
58
59 public void destroy() {
60 ;
61 }
62
63
64 public void startUpHandler() {
65 ;
66 }
67
68
69 public void startDownHandler() {
70 ;
71 }
72
73 public void up(Event evt) {
74 Header h;
75 Message msg;
76 int type;
77
78 if(evt.getType() == Event.MSG) {
79 msg=(Message)evt.getArg();
80 h=msg.removeHeader(name);
81 if(h != null && h instanceof BshHeader) {
82 type=((BshHeader)h).type;
83 switch(type) {
84 case BshHeader.REQ:
85 handleRequest(msg.getSrc(), msg.getBuffer());
86 return;
87 case BshHeader.RSP:
88 msg.putHeader(name, h);
89 passUp(evt);
90 return;
91 case BshHeader.DESTROY_INTERPRETER:
92 destroyInterpreter();
93 return;
94 default:
95 if(log.isErrorEnabled()) log.error("header type was not REQ as expected" +
96 " (was " + type + ')');
97 return;
98 }
99 }
100 }
101 passUp(evt);
102 }
103
104
105 void handleRequest(Address sender, byte[] buf) {
106 Object retval;
107 String code;
108
109
110 if(buf == null) {
111 if(log.isErrorEnabled()) log.error("buffer was null");
112 return;
113 }
114
115 code=new String (buf);
116
117 if(interpreter == null) {
119 interpreter=new Interpreter();
120
121 if(log.isInfoEnabled()) log.info("beanshell interpreter was created");
122 try {
123 interpreter.set("bsh_prot", this);
124
125 if(log.isInfoEnabled()) log.info("set \"bsh_prot\" to " + this);
126 }
127 catch(EvalError err) {
128 if(log.isErrorEnabled()) log.error("failed setting \"bsh_prot\": " + err);
129 }
130
131 }
132
133 try {
134 retval=interpreter.eval(code);
135
136 if(log.isInfoEnabled()) log.info("eval: \"" + code +
137 "\", retval=" + retval);
138 }
139 catch(EvalError ex) {
140 if(log.isErrorEnabled()) log.error("error is " + Util.getStackTrace(ex));
141 retval=ex;
142 }
143
144 if(sender != null) {
145 Message rsp=new Message(sender, null, null);
146
147 if(retval != null) {
150 if(retval instanceof Serializable )
151 rsp.setObject((Serializable )retval);
152 else
153 rsp.setObject(retval.toString());
154 }
155
156
157 if(log.isInfoEnabled()) log.info("sending back response " +
158 retval + " to " + rsp.getDest());
159 rsp.putHeader(name, new BshHeader(BshHeader.RSP));
160 passDown(new Event(Event.MSG, rsp));
161 }
162 }
163
164
165
166 public void destroyInterpreter() {
188 interpreter=null;
190 if(log.isInfoEnabled()) log.info("beanshell interpreter was destroyed");
191 }
192
193
194
195 public static class BshHeader extends Header {
196 public static final int REQ=1;
197 public static final int RSP=2;
198 public static final int DESTROY_INTERPRETER=3;
199 int type=REQ;
200
201
202 public BshHeader() {
203 ; }
205
206 public BshHeader(int type) {
207 this.type=type;
208 }
209
210 public long size() {
211 return 10;
212 }
213
214 public String toString() {
215 StringBuffer sb=new StringBuffer ();
216 if(type == REQ)
217 sb.append("REQ");
218 else
219 if(type == RSP)
220 sb.append("RSP");
221 else
222 if(type == DESTROY_INTERPRETER)
223 sb.append("DESTROY_INTERPRETER");
224 else
225 sb.append("<unknown type>");
226 return sb.toString();
227 }
228
229 public void writeExternal(ObjectOutput out) throws IOException {
230 out.writeInt(type);
231 }
232
233 public void readExternal(ObjectInput in) throws IOException , ClassNotFoundException {
234 type=in.readInt();
235 }
236
237 }
238
239 }
240 |
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