/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mina.integration.ognl;
import java.util.LinkedHashSet;
import java.util.Set;
import ognl.Ognl;
import ognl.OgnlContext;
import ognl.OgnlException;
import ognl.TypeConverter;
import org.apache.mina.core.session.IoSession;
/**
* Finds {@link IoSession}s that match a boolean OGNL expression.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (Thu, 26 Jun 2008) $
*/
public class IoSessionFinder {
private final String query;
private final TypeConverter typeConverter = new PropertyTypeConverter();
private final Object expression;
/**
* Creates a new instance with the specified OGNL expression that returns
* a boolean value (e.g. <tt>"id == 0x12345678"</tt>).
*/
public IoSessionFinder(String query) {
if (query == null) {
throw new NullPointerException("query");
}
query = query.trim();
if (query.length() == 0) {
throw new IllegalArgumentException("query is empty.");
}
this.query = query;
try {
expression = Ognl.parseExpression(query);
} catch (OgnlException e) {
throw new IllegalArgumentException("query: " + query);
}
}
/**
* Finds a {@link Set} of {@link IoSession}s that matches the query
* from the specified sessions and returns the matches.
* @throws OgnlException if failed to evaluate the OGNL expression
*/
public Set<IoSession> find(Iterable<IoSession> sessions) throws OgnlException {
if (sessions == null) {
throw new NullPointerException("sessions");
}
Set<IoSession> answer = new LinkedHashSet<IoSession>();
for (IoSession s: sessions) {
OgnlContext context = (OgnlContext) Ognl.createDefaultContext(s);
context.setTypeConverter(typeConverter);
context.put(AbstractPropertyAccessor.READ_ONLY_MODE, true);
context.put(AbstractPropertyAccessor.QUERY, query);
Object result = Ognl.getValue(expression, context, s);
if (result instanceof Boolean) {
if (((Boolean) result).booleanValue()) {
answer.add(s);
}
} else {
throw new OgnlException(
"Query didn't return a boolean value: " + query);
}
}
return answer;
}
}