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1
8 package org.apache.avalon.excalibur.util;
9
10 import java.util.ArrayList  ;
11 import java.util.HashMap ;
12 import java.util.Iterator ;
13 import java.util.List ;
14 import java.util.Map ;
15
16
23 public class Circuit
24 {
25 protected Map m_map;
26
27 public Circuit()
28 {
29 m_map = new HashMap ();
30 }
31
32 public void addNode( final String name )
33 {
34 if( null == m_map.get( name ) )
35 {
36 m_map.put( name, new Node( name ) );
37 }
38 }
39
40 public void removeNode( final String name )
41 {
42 String tmp = null;
43 Iterator e = m_map.keySet().iterator();
44
45 while( e.hasNext() )
46 {
47 tmp = (String )e.next();
48
49 if( !tmp.equals( name ) )
50 {
51 try { unlink( tmp, name ); }
52 catch( final CircuitException ce) {}
53 try { unlink( name, tmp ); }
54 catch( final CircuitException ce ) {}
55 }
56
57 }
58
59 m_map.remove( name );
60 }
61
62 public void link( final String parent, final String child )
63 throws CircuitException
64 {
65 Node tempNode = null;
66 final Node pnode = (Node)m_map.get( parent );
67 final Node cnode = (Node)m_map.get( child );
68 if( null == pnode )
69 {
70 throw new CircuitException( "Unknown node " + parent );
71 }
72 else if( null == cnode )
73 {
74 throw new CircuitException( "Unknown node " + child );
75 }
76 else if( pnode.isChildOf( cnode ) )
77 {
78 throw new CircuitException( "Loop! Node " + parent +
79 " is already child of node " + child );
80 }
81 else
82 {
83 final Iterator e = m_map.values().iterator();
84
85 while( e.hasNext() )
86 {
87 tempNode = (Node)e.next();
88 if( tempNode.isChildOf( cnode ) )
89 {
90 tempNode.m_parents.addAll( pnode.m_parents );
91 }
92 }
93 }
94 }
95
96 public void unlink( final String parent, final String child )
97 throws CircuitException
98 {
99 final Node cnode = (Node)m_map.get( child );
100 final Node pnode = (Node)m_map.get( parent );
101
102 if( cnode.m_parents.contains( pnode ) )
103 {
104 Node tempNode = null;
105 final Iterator e = m_map.values().iterator();
106
107 while( e.hasNext() )
108 {
109 tempNode = (Node)e.next();
110
111 if( tempNode.m_parents.contains( cnode ) )
112 {
113 tempNode.m_parents.removeAll( pnode.m_parents );
114 }
115 }
116 }
117 else
118 {
119 throw new CircuitException( "Node " + parent + " is not parent of node " + child );
120 }
121 }
122
123 public List getAncestors()
124 {
125 final List ancestors = new ArrayList (5);
126 String name = null;
127 Node tempNode = null;
128 final Iterator e = m_map.keySet().iterator();
129
130 while( e.hasNext() )
131 {
132 name = (String )e.next();
133 tempNode = (Node)m_map.get( name );
134
135 if( 1 == tempNode.m_parents.size() )
136 {
137 ancestors.add( name );
138 }
139 }
140
141 return ancestors;
142 }
143
144 public String getAncestor()
145 {
146 String name = null;
147 Node tempNode = null;
148 final Iterator e = m_map.keySet().iterator();
149
150 while( e.hasNext() )
151 {
152 name = (String )e.next();
153 tempNode = (Node)m_map.get( name );
154
155 if( 1 == tempNode.m_parents.size() )
156 {
157 return name;
158 }
159 }
160
161 return null;
162 }
163
164 public boolean isEmpty()
165 {
166 return m_map.isEmpty();
167 }
168
169 protected final class Node
170 {
171 protected final List m_parents;
172 protected final String m_name;
173
174 protected Node( final String name )
175 {
176 m_parents = new ArrayList ( 5 );
177 m_parents.add( this );
178 m_name = name;
179 }
180
181 protected final boolean isChildOf( final Node parent )
182 {
183 return m_parents.contains( parent );
184 }
185
186 public final String toString()
187 {
188 StringBuffer buffer = new StringBuffer ();
189 Iterator e = m_parents.iterator();
190 buffer.append( m_name + "[" );
191
192 while( e.hasNext() )
193 {
194 buffer.append(((Node) e.next()).m_name + " ");
195 }
196
197 buffer.append("]");
198 return buffer.toString();
199 }
200 }
201
202 public final class CircuitException
203 extends RuntimeException
204 {
205 public CircuitException()
206 {
207 }
208
209 public CircuitException( final String message )
210 {
211 super( message );
212 }
213 }
214
215 public String toString()
216 {
217 StringBuffer buffer = new StringBuffer ();
218 String name = null;
219 Node tempNode = null;
220 final Iterator e = m_map.keySet().iterator();
221
222 while( e.hasNext() )
223 {
224 name = (String )e.next();
225 tempNode = (Node)m_map.get( name );
226 buffer.append( name ).append( "(" )
227 .append( tempNode.m_parents.size() - 1 )
228 .append( ") " );
229 }
230
231 return buffer.toString();
232 }
233 }
234
235 |
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