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.mina.integration.ognl;
18
19 import java.util.LinkedHashSet;
20 import java.util.Set;
21
22 import ognl.Ognl;
23 import ognl.OgnlContext;
24 import ognl.OgnlException;
25 import ognl.TypeConverter;
26
27 import org.apache.mina.core.session.IoSession;
28
29 /**
30 * Finds {@link IoSession}s that match a boolean OGNL expression.
31 *
32 * @author The Apache MINA Project (dev@mina.apache.org)
33 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $
34 */
35 public class IoSessionFinder {
36
37 private final String query;
38 private final TypeConverter typeConverter = new PropertyTypeConverter();
39 private final Object expression;
40
41 /**
42 * Creates a new instance with the specified OGNL expression that returns
43 * a boolean value (e.g. <tt>"id == 0x12345678"</tt>).
44 */
45 public IoSessionFinder(String query) {
46 if (query == null) {
47 throw new NullPointerException("query");
48 }
49
50 query = query.trim();
51 if (query.length() == 0) {
52 throw new IllegalArgumentException("query is empty.");
53 }
54
55 this.query = query;
56 try {
57 expression = Ognl.parseExpression(query);
58 } catch (OgnlException e) {
59 throw new IllegalArgumentException("query: " + query);
60 }
61 }
62
63 /**
64 * Finds a {@link Set} of {@link IoSession}s that matches the query
65 * from the specified sessions and returns the matches.
66 * @throws OgnlException if failed to evaluate the OGNL expression
67 */
68 public Set<IoSession> find(Iterable<IoSession> sessions) throws OgnlException {
69 if (sessions == null) {
70 throw new NullPointerException("sessions");
71 }
72
73 Set<IoSession> answer = new LinkedHashSet<IoSession>();
74 for (IoSession s: sessions) {
75 OgnlContext context = (OgnlContext) Ognl.createDefaultContext(s);
76 context.setTypeConverter(typeConverter);
77 context.put(AbstractPropertyAccessor.READ_ONLY_MODE, true);
78 context.put(AbstractPropertyAccessor.QUERY, query);
79 Object result = Ognl.getValue(expression, context, s);
80 if (result instanceof Boolean) {
81 if (((Boolean) result).booleanValue()) {
82 answer.add(s);
83 }
84 } else {
85 throw new OgnlException(
86 "Query didn't return a boolean value: " + query);
87 }
88 }
89
90 return answer;
91 }
92 }