01: package org.drools.ruleflow.core.impl;
02:
03: /*
04: * Copyright 2005 JBoss Inc
05: *
06: * Licensed under the Apache License, Version 2.0 (the "License");
07: * you may not use this file except in compliance with the License.
08: * You may obtain a copy of the License at
09: *
10: * http://www.apache.org/licenses/LICENSE-2.0
11: *
12: * Unless required by applicable law or agreed to in writing, software
13: * distributed under the License is distributed on an "AS IS" BASIS,
14: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15: * See the License for the specific language governing permissions and
16: * limitations under the License.
17: */
18:
19: import java.util.List;
20:
21: import org.drools.ruleflow.core.Connection;
22: import org.drools.ruleflow.core.StartNode;
23:
24: /**
25: * Default implementation of a start node.
26: *
27: * @author <a href="mailto:kris_verlaenen@hotmail.com">Kris Verlaenen</a>
28: */
29: public class StartNodeImpl extends NodeImpl implements StartNode {
30:
31: private static final long serialVersionUID = 400L;
32:
33: public Connection getTo() {
34: final List list = getOutgoingConnections();
35: if (list.size() > 0) {
36: return (Connection) list.get(0);
37: }
38: return null;
39: }
40:
41: protected void validateAddOutgoingConnection(
42: final Connection connection) {
43: super .validateAddOutgoingConnection(connection);
44: if (getOutgoingConnections().size() > 0) {
45: throw new IllegalArgumentException(
46: "A start node cannot have more than one outgoing connection");
47: }
48: }
49:
50: protected void validateAddIncomingConnection(
51: final Connection connection) {
52: throw new UnsupportedOperationException(
53: "A start node does not have an incoming connection");
54: }
55:
56: protected void validateRemoveIncomingConnection(
57: final Connection connection) {
58: throw new UnsupportedOperationException(
59: "A start node does not have an incoming connection");
60: }
61:
62: }
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