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 */
34 public class IoSessionFinder {
35
36 private final String query;
37 private final TypeConverter typeConverter = new PropertyTypeConverter();
38 private final Object expression;
39
40 /**
41 * Creates a new instance with the specified OGNL expression that returns
42 * a boolean value (e.g. <tt>"id == 0x12345678"</tt>).
43 */
44 public IoSessionFinder(String query) {
45 if (query == null) {
46 throw new NullPointerException("query");
47 }
48
49 query = query.trim();
50 if (query.length() == 0) {
51 throw new IllegalArgumentException("query is empty.");
52 }
53
54 this.query = query;
55 try {
56 expression = Ognl.parseExpression(query);
57 } catch (OgnlException e) {
58 throw new IllegalArgumentException("query: " + query);
59 }
60 }
61
62 /**
63 * Finds a {@link Set} of {@link IoSession}s that matches the query
64 * from the specified sessions and returns the matches.
65 * @throws OgnlException if failed to evaluate the OGNL expression
66 */
67 public Set<IoSession> find(Iterable<IoSession> sessions) throws OgnlException {
68 if (sessions == null) {
69 throw new NullPointerException("sessions");
70 }
71
72 Set<IoSession> answer = new LinkedHashSet<IoSession>();
73 for (IoSession s: sessions) {
74 OgnlContext context = (OgnlContext) Ognl.createDefaultContext(s);
75 context.setTypeConverter(typeConverter);
76 context.put(AbstractPropertyAccessor.READ_ONLY_MODE, true);
77 context.put(AbstractPropertyAccessor.QUERY, query);
78 Object result = Ognl.getValue(expression, context, s);
79 if (result instanceof Boolean) {
80 if (((Boolean) result).booleanValue()) {
81 answer.add(s);
82 }
83 } else {
84 throw new OgnlException(
85 "Query didn't return a boolean value: " + query);
86 }
87 }
88
89 return answer;
90 }
91 }