1 /*
2 * (C) 2002 David Carr david@carr.name
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19 package net.sourceforge.mflow.impl;
20
21 import java.util.ArrayList;
22 import java.util.Arrays;
23 import java.util.List;
24
25 import net.sourceforge.mflow.api.MsgFlowComponent;
26 import net.sourceforge.mflow.api.MsgSource;
27
28 /***
29 * Contains various algorithms for MsgFlowComponents
30 *
31 * @author <a href="mailto:david@carr.name">David Carr</a>
32 * @version $Revision: 1.4 $
33 */
34 class Algorithm {
35 private Algorithm() {
36 //prevent external construction
37 }
38
39 private static class ReceiverContainer {
40 private List receivers;
41 private boolean isDone = false;
42
43 ReceiverContainer(MsgFlowComponent comp) {
44 if (comp instanceof MsgSource) {
45 MsgSource src = (MsgSource) comp;
46 this.receivers = new ArrayList(Arrays.asList(src.getReceivers()));
47 } else {
48 this.receivers = new ArrayList();
49 }
50 }
51
52 void remove(MsgFlowComponent c) {
53 this.receivers.remove(c);
54 }
55
56 int size() {
57 if (this.isDone) {
58 return -1;
59 } else {
60 return this.receivers.size();
61 }
62 }
63
64 void done() {
65 this.isDone = true;
66 }
67 }
68
69 /***
70 * Returns a new array of components containing the original components,
71 * sorted. The passed array should not contain any circuits, and all
72 * receivers should be included in the array
73 *
74 * @param components the components to sort
75 * @return a sorted array of the same components, or null if passed an
76 * invalid array
77 * @todo ensure that all child components are within the array
78 */
79 static MsgFlowComponent[] sortComponents(MsgFlowComponent[] components) {
80 if (components == null)
81 return null;
82 ReceiverContainer[] receivers = new ReceiverContainer[components.length];
83 for (int i = 0; i < components.length; i++) {
84 receivers[i] = new ReceiverContainer(components[i]);
85 }
86 MsgFlowComponent[] sorted = new MsgFlowComponent[components.length];
87 for (int index = sorted.length - 1; index >= 0; index--) {
88 int i;
89 for (i = 0; i < receivers.length; i++) {
90 if (receivers[i].size() == 0) {
91 sorted[index] = components[i];
92 for (int j = 0; j < components.length; j++) {
93 receivers[j].remove(components[i]);
94 //will be ignored if not applicable
95 }
96 receivers[i].done();
97 break; //skip out of this loop to continue on the next
98 }
99 }
100 if (i == receivers.length) {
101 return null; //must be a component not in the array
102 }
103 }
104 return sorted;
105 }
106 }
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