SymbolList


1   /*
2    *  Copyright (C) Chaperon. All rights reserved.
3    *  -------------------------------------------------------------------------
4    *  This software is published under the terms of the Apache Software License
5    *  version 1.1, a copy of which has been included  with this distribution in
6    *  the LICENSE file.
7    */
8   
9   package net.sourceforge.chaperon.model.symbol;
10  
11  import java.io.Serializable  ;
12  
13  /**
14   * This class represents a list of symbols.
15   *
16   * @author <a HREF="mailto:stephan@apache.org">Stephan Michels</a>
17   * @version CVS $Id: SymbolList.java,v 1.7 2003/12/09 19:55:53 benedikta Exp $
18   */
19  public class SymbolList implements SymbolCollection, Serializable  , Cloneable  
20  {
21    private int capacityIncrement = 100;
22    private int elementCount = 0;
23    private Symbol[] list = new Symbol[10];
24  
25    /**
26     * Creates a empty list of symbols.
27     */
28    public SymbolList() {}
29  
30    /*
31     * Add a symbol to this list.
32     *
33     * @param symbol Symbol, which should added.
34     *
35     * @return Index of the symbol in this list.
36     */
37    public boolean addSymbol(Symbol symbol)
38    {
39      if (symbol==null)
40        throw new NullPointerException  ("Symbol is null");
41  
42      ensureCapacity(elementCount+1);
43      list[elementCount] = symbol;
44      elementCount++;
45      return true;
46    }
47  
48    /*
49     * Add the symbols from another list to this list
50     *
51     * @param collection Collection of symbols.
52     */
53    public boolean addSymbol(SymbolCollection collection)
54    {
55      if (collection==null)
56        throw new NullPointerException  ("Symbol collection is null");
57  
58      for (int i = 0; i<collection.getSymbolCount(); i++)
59        addSymbol(collection.getSymbol(i));
60  
61      return true;
62    }
63  
64    /**
65     * Removes a symbol by an index from this list.
66     *
67     * @param index Index of the symbol.
68     */
69    public void removeSymbol(int index)
70    {
71      if (index>=elementCount)
72        throw new ArrayIndexOutOfBoundsException  (index);
73  
74      elementCount--;
75      if (index<elementCount)
76        System.arraycopy(list, index+1, list, index, elementCount-index);
77    }
78  
79    /**
80     * Removes a symbol from this list.
81     *
82     * @param symbol Symbol, which should be removed.
83     */
84    public void removeSymbol(Symbol symbol)
85    {
86      if (symbol==null)
87        throw new NullPointerException  ("Symbol is null");
88  
89      for (int i = elementCount-1; i>=0; i--)
90        if (symbol.equals(list[i]))
91          removeSymbol(i);
92    }
93  
94    /**
95     * Replace a symbol by an index.
96     *
97     * @param index The index, at which the symbol be inserted.
98     * @param symbol Symbol.
99     */
100   public void setSymbol(int index, Symbol symbol)
101   {
102     if (index>=elementCount)
103       throw new ArrayIndexOutOfBoundsException  (index);
104 
105     if (symbol==null)
106       throw new NullPointerException  ("Symbol is null");
107 
108     list[index] = symbol;
109   }
110 
111   /**
112    * Return a symbol giving by an index.
113    *
114    * @param index Index of the symbol.
115    *
116    * @return Symbol.
117    */
118   public Symbol getSymbol(int index)
119   {
120     if ((index<0) && (index>=elementCount))
121       throw new IndexOutOfBoundsException  ();
122 
123     return list[index];
124   }
125 
126   /**
127    * Returns a symbol from this list given by the name of the symbol.
128    *
129    * @param name Name of the symbol.
130    *
131    * @return Symbol.
132    */
133   public Symbol getSymbol(String   name)
134   {
135     int index = indexOf(name);
136 
137     if (index>=0)
138       return list[index];
139 
140     return null;
141   }
142 
143   /**
144    * Returns the count of symbols in the list.
145    *
146    * @return Count of symbol.
147    */
148   public int getSymbolCount()
149   {
150     return elementCount;
151   }
152 
153   /**
154    * If this list is empty.
155    *
156    * @return True, if the list is empty.
157    */
158   public boolean isEmpty()
159   {
160     return elementCount==0;
161   }
162 
163   /**
164    * Return the index of a symbol.
165    *
166    * @param symbol Symbol.
167    *
168    * @return Index of this symbol.
169    */
170   public int indexOf(Symbol symbol)
171   {
172     if (symbol==null)
173       throw new NullPointerException  ("Symbol is null");
174 
175     for (int i = 0; i<elementCount; i++)
176       if (list[i].equals(symbol))
177         return i;
178 
179     return -1;
180   }
181 
182   /**
183    * Return the index of a symbol, given by the name of the Symbol.
184    *
185    * @param name Name of symbol.
186    *
187    * @return Index of this symbol.
188    */
189   public int indexOf(String   name)
190   {
191     if (name==null)
192       throw new NullPointerException  ("Name is null");
193 
194     for (int i = 0; i<elementCount; i++)
195       if (list[i].getName().equals(name))
196         return i;
197 
198     return -1;
199   }
200 
201   /**
202    * If the list contains a symbol.
203    *
204    * @param symbol Symbol
205    *
206    * @return True, if the list contains the symbol
207    */
208   public boolean contains(Symbol symbol)
209   {
210     if (symbol==null)
211       throw new NullPointerException  ("Symbol is null");
212 
213     for (int i = 0; i<elementCount; i++)
214       if (list[i].equals(symbol))
215         return true;
216 
217     return false;
218   }
219 
220   /**
221    * If the list contains a symbol, given by the name of the symbol.
222    *
223    * @param name Name of the symbol.
224    *
225    * @return True, if the list contains the symbol.
226    */
227   public boolean contains(String   name)
228   {
229     if (name==null)
230       throw new NullPointerException  ("Name is null");
231 
232     for (int i = 0; i<elementCount; i++)
233       if (list[i].getName().equals(name))
234         return true;
235 
236     return false;
237   }
238 
239   /**
240    * Removes all symbols from this list.
241    */
242   public void clear()
243   {
244     elementCount = 0;
245   }
246 
247   /**
248    * Return all used terminal symbols in this list.
249    *
250    * @return Set of terminal symbols.
251    */
252   public SymbolSet getTerminals()
253   {
254     SymbolSet set = new SymbolSet();
255 
256     Symbol symbol;
257 
258     for (int i = 0; i<elementCount; i++)
259       if ((symbol = this.list[i]) instanceof Terminal)
260         set.addSymbol(symbol);
261 
262     return set;
263   }
264 
265   /**
266    * Return all used non terminal symbols in this list.
267    *
268    * @return Set of nonterminal symbols.
269    */
270   public SymbolSet getNonterminals()
271   {
272     SymbolSet set = new SymbolSet();
273 
274     Symbol symbol;
275 
276     for (int i = 0; i<elementCount; i++)
277       if ((symbol = this.list[i]) instanceof Nonterminal)
278         set.addSymbol(symbol);
279 
280     return set;
281   }
282 
283   /**
284    * Compares to another list of symbols.
285    *
286    * @param o Another object.
287    *
288    * @return True, if both lists contains the same symbols.
289    */
290   public boolean equals(Object   o)
291   {
292     if (o==this)
293       return true;
294 
295     if (o instanceof SymbolList)
296     {
297       SymbolList list = (SymbolList)o;
298 
299       if (elementCount!=list.getSymbolCount())
300         return false;
301 
302       for (int i = 0; i<list.getSymbolCount(); i++)
303         if (!getSymbol(i).equals(list.getSymbol(i)))
304           return false;
305 
306       return true;
307     }
308 
309     return false;
310   }
311 
312   /**
313    * Return a string representation of the list.
314    *
315    * @return String representation of the list.
316    */
317   public String   toString()
318   {
319     StringBuffer   buffer = new StringBuffer  ();
320 
321     for (int i = 0; i<elementCount; i++)
322     {
323       buffer.append(list[i].toString());
324       if (i<(elementCount-1))
325         buffer.append(" ");
326     }
327 
328     return buffer.toString();
329   }
330 
331   /**
332    * Create a clone of this list of symbols
333    *
334    * @return Clone of this list.
335    *
336    * @throws CloneNotSupportedException If a exception occurs during the cloning.
337    */
338   public Object   clone()
339   {
340     SymbolList clone = new SymbolList();
341 
342     for (int i = 0; i<getSymbolCount(); i++)
343       clone.addSymbol(getSymbol(i));
344 
345     return clone;
346   }
347 
348   /**
349    * Ensure the capacity for adding values
350    *
351    * @param minCapacity
352    */
353   private void ensureCapacity(int minCapacity)
354   {
355     if (list.length>=minCapacity)
356       return;
357 
358     int newCapacity = list.length+capacityIncrement;
359 
360     if (capacityIncrement<=0)
361       newCapacity = list.length*2;
362 
363     Symbol[] newArray = new Symbol[Math.max(newCapacity, minCapacity)];
364 
365     System.arraycopy(list, 0, newArray, 0, list.length);
366     list = newArray;
367   }
368 }
369
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