001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.mina.integration.ognl; 018 019import java.util.LinkedHashSet; 020import java.util.Set; 021 022import ognl.Ognl; 023import ognl.OgnlContext; 024import ognl.OgnlException; 025import ognl.TypeConverter; 026 027import org.apache.mina.core.session.IoSession; 028 029/** 030 * Finds {@link IoSession}s that match a boolean OGNL expression. 031 * 032 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 033 */ 034public class IoSessionFinder { 035 036 private final String query; 037 038 private final TypeConverter typeConverter = new PropertyTypeConverter(); 039 040 private final Object expression; 041 042 /** 043 * Creates a new instance with the specified OGNL expression that returns 044 * a boolean value (e.g. <tt>"id == 0x12345678"</tt>). 045 * 046 * @param query The OGNL expression 047 */ 048 public IoSessionFinder(String query) { 049 if (query == null) { 050 throw new IllegalArgumentException("query"); 051 } 052 053 query = query.trim(); 054 055 if (query.length() == 0) { 056 throw new IllegalArgumentException("query is empty."); 057 } 058 059 // Only accept queries like [a-zA-Z_$ ]+ (== | < | > | <= | >=) [a-zA-Z\-$\.0-9 ]+ 060 int comp = -1; 061 062 for (int i=0; i<query.length();i++) { 063 char c = query.charAt(i); 064 065 if ((c == '=') || (c == '<') || (c == '>') || (c == '!')) { 066 comp = i; 067 } else if ( !Character.isJavaIdentifierPart(c) && (c != ' ')) { 068 throw new IllegalArgumentException("Invalid query."); 069 } else { 070 if ( comp > 0) { 071 break; 072 } 073 } 074 } 075 076 if (comp<=0) { 077 throw new IllegalArgumentException("Invalid query."); 078 } 079 080 for (int i=comp+1; i<query.length();i++) { 081 char c = query.charAt(i); 082 083 if (!Character.isJavaIdentifierPart(c) && (c != ' ') && (c != '"') && (c != '\'')) { 084 throw new IllegalArgumentException("Invalid query."); 085 } 086 } 087 088 this.query = query; 089 090 try { 091 expression = Ognl.parseExpression(query); 092 } catch (OgnlException e) { 093 throw new IllegalArgumentException("query: " + query); 094 } 095 } 096 097 /** 098 * Finds a {@link Set} of {@link IoSession}s that matches the query 099 * from the specified sessions and returns the matches. 100 * @throws OgnlException if failed to evaluate the OGNL expression 101 * 102 * @param sessions The list of sessions to check 103 * @return A set of the session that matches the query 104 * @throws OgnlException If we can't find a boolean value in a session's context 105 */ 106 public Set<IoSession> find(Iterable<IoSession> sessions) throws OgnlException { 107 if (sessions == null) { 108 throw new IllegalArgumentException("sessions"); 109 } 110 111 Set<IoSession> answer = new LinkedHashSet<IoSession>(); 112 113 for (IoSession s : sessions) { 114 OgnlContext context = (OgnlContext) Ognl.createDefaultContext(s); 115 context.setTypeConverter(typeConverter); 116 context.put(AbstractPropertyAccessor.READ_ONLY_MODE, true); 117 context.put(AbstractPropertyAccessor.QUERY, query); 118 Object result = Ognl.getValue(expression, context, s); 119 120 if (result instanceof Boolean) { 121 if (((Boolean) result).booleanValue()) { 122 answer.add(s); 123 } 124 } else { 125 throw new OgnlException("Query didn't return a boolean value: " + query); 126 } 127 } 128 129 return answer; 130 } 131}