Coverage Report

Coverage Report - org.apache.commons.configuration.ConfigurationKey

Classes in this File

Line Coverage

Branch Coverage

Complexity

ConfigurationKey

98%

65/66

100%

15/15

1,833

ConfigurationKey$KeyIterator

92%

55/60

100%

13/13

1,833

 /*
  * 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.commons.configuration;
 
 import java.io.Serializable;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
 /**
  * <p>A simple class that supports creation of and iteration on complex
  * configuration keys.</p>
  *
  * <p>For key creation the class works similar to a StringBuffer: There are
  * several <code>appendXXXX()</code> methods with which single parts
  * of a key can be constructed. All these methods return a reference to the
  * actual object so they can be written in a chain. When using this methods
  * the exact syntax for keys need not be known.</p>
  *
  * <p>This class also defines a specialized iterator for configuration keys.
  * With such an iterator a key can be tokenized into its single parts. For
  * each part it can be checked whether it has an associated index.</p>
  *
  * @author <a href="mailto:oliver.heger@t-online.de">Oliver Heger</a>
  * @version $Id: ConfigurationKey.java 439648 2006-09-02 20:42:10Z oheger $
  */
 public class ConfigurationKey implements Serializable
 {
     /** Constant for a property delimiter.*/
     public static final char PROPERTY_DELIMITER = '.';
 
     /** Constant for an escaped delimiter. */
     public static final String ESCAPED_DELIMITER =
         String.valueOf(PROPERTY_DELIMITER) + String.valueOf(PROPERTY_DELIMITER);
 
     /** Constant for an attribute start marker.*/
     private static final String ATTRIBUTE_START = "[@";
 
     /** Constant for an attribute end marker.*/
     private static final String ATTRIBUTE_END = "]";
 
     /** Constant for an index start marker.*/
     private static final char INDEX_START = '(';
 
     /** Constant for an index end marker.*/
     private static final char INDEX_END = ')';
 
     /** Constant for the initial StringBuffer size.*/
     private static final int INITIAL_SIZE = 32;
 
     /**
      * The serial version ID.
      */
     private static final long serialVersionUID = -4299732083605277656L;
 
     /** Holds a buffer with the so far created key.*/
     private StringBuffer keyBuffer;
 
     /**
      * Creates a new, empty instance of <code>ConfigurationKey</code>.
      */
     public ConfigurationKey()
     {
         keyBuffer = new StringBuffer(INITIAL_SIZE);
     }
 
     /**
      * Creates a new instance of <code>ConfigurationKey</code> and
      * initializes it with the given key.
      *
      * @param key the key as a string
      */
     public ConfigurationKey(String key)
     {
         keyBuffer = new StringBuffer(key);
         removeTrailingDelimiter();
     }
 
     /**
      * Appends the name of a property to this key. If necessary, a
      * property delimiter will be added.
      *
      * @param property the name of the property to be added
      * @return a reference to this object
      */
     public ConfigurationKey append(String property)
     {
         if (keyBuffer.length() > 0 && !hasDelimiter() && !isAttributeKey(property))
         {
             keyBuffer.append(PROPERTY_DELIMITER);
         }
 
         keyBuffer.append(property);
         removeTrailingDelimiter();
         return this;
     }
 
     /**
      * Appends an index to this configuration key.
      *
      * @param index the index to be appended
      * @return a reference to this object
      */
     public ConfigurationKey appendIndex(int index)
     {
         keyBuffer.append(INDEX_START).append(index);
         keyBuffer.append(INDEX_END);
         return this;
     }
 
     /**
      * Appends an attribute to this configuration key.
      *
      * @param attr the name of the attribute to be appended
      * @return a reference to this object
      */
     public ConfigurationKey appendAttribute(String attr)
     {
         keyBuffer.append(constructAttributeKey(attr));
         return this;
     }
 
     /**
      * Checks if this key is an attribute key.
      *
      * @return a flag if this key is an attribute key
      */
     public boolean isAttributeKey()
     {
         return isAttributeKey(keyBuffer.toString());
     }
 
     /**
      * Checks if the passed in key is an attribute key. Such attribute keys
      * start and end with certain marker strings. In some cases they must be
      * treated slightly different.
      *
      * @param key the key (part) to be checked
      * @return a flag if this key is an attribute key
      */
     public static boolean isAttributeKey(String key)
     {
         return key != null
         && key.startsWith(ATTRIBUTE_START)
         && key.endsWith(ATTRIBUTE_END);
     }
 
     /**
      * Decorates the given key so that it represents an attribute. Adds
      * special start and end markers.
      *
      * @param key the key to be decorated
      * @return the decorated attribute key
      */
     public static String constructAttributeKey(String key)
     {
         StringBuffer buf = new StringBuffer();
         buf.append(ATTRIBUTE_START).append(key).append(ATTRIBUTE_END);
         return buf.toString();
     }
 
     /**
      * Extracts the name of the attribute from the given attribute key.
      * This method removes the attribute markers - if any - from the
      * specified key.
      *
      * @param key the attribute key
      * @return the name of the corresponding attribute
      */
     public static String attributeName(String key)
     {
         return isAttributeKey(key) ? removeAttributeMarkers(key) : key;
     }
 
     /**
      * Helper method for removing attribute markers from a key.
      *
      * @param key the key
      * @return the key with removed attribute markers
      */
     static String removeAttributeMarkers(String key)
     {
         return key.substring(ATTRIBUTE_START.length(), key.length() - ATTRIBUTE_END.length());
     }
 
     /**
      * Helper method that checks if the actual buffer ends with a property
      * delimiter.
      *
      * @return a flag if there is a trailing delimiter
      */
     private boolean hasDelimiter()
     {
         int count = 0;
         for (int idx = keyBuffer.length() - 1; idx >= 0
                 && keyBuffer.charAt(idx) == PROPERTY_DELIMITER; idx--)
         {
             count++;
         }
         return count % 2 == 1;
     }
 
     /**
      * Removes a trailing delimiter if there is any.
      */
     private void removeTrailingDelimiter()
     {
         while (hasDelimiter())
         {
             keyBuffer.deleteCharAt(keyBuffer.length() - 1);
         }
     }
 
     /**
      * Returns a string representation of this object. This is the
      * configuration key as a plain string.
      *
      * @return a string for this object
      */
     public String toString()
     {
         return keyBuffer.toString();
     }
 
     /**
      * Returns an iterator for iterating over the single components of
      * this configuration key.
      *
      * @return an iterator for this key
      */
     public KeyIterator iterator()
     {
         return new KeyIterator();
     }
 
     /**
      * Returns the actual length of this configuration key.
      *
      * @return the length of this key
      */
     public int length()
     {
         return keyBuffer.length();
     }
 
     /**
      * Sets the new length of this configuration key. With this method it is
      * possible to truncate the key, e.g. to return to a state prior calling
      * some <code>append()</code> methods. The semantic is the same as
      * the <code>setLength()</code> method of <code>StringBuffer</code>.
      *
      * @param len the new length of the key
      */
     public void setLength(int len)
     {
         keyBuffer.setLength(len);
     }
 
     /**
      * Checks if two <code>ConfigurationKey</code> objects are equal. The
      * method can be called with strings or other objects, too.
      *
      * @param c the object to compare
      * @return a flag if both objects are equal
      */
     public boolean equals(Object c)
     {
         if (c == null)
         {
             return false;
         }
 
         return keyBuffer.toString().equals(c.toString());
     }
 
     /**
      * Returns the hash code for this object.
      *
      * @return the hash code
      */
     public int hashCode()
     {
         return String.valueOf(keyBuffer).hashCode();
     }
 
     /**
      * Returns a configuration key object that is initialized with the part
      * of the key that is common to this key and the passed in key.
      *
      * @param other the other key
      * @return a key object with the common key part
      */
     public ConfigurationKey commonKey(ConfigurationKey other)
     {
         if (other == null)
         {
             throw new IllegalArgumentException("Other key must no be null!");
         }
 
         ConfigurationKey result = new ConfigurationKey();
         KeyIterator it1 = iterator();
         KeyIterator it2 = other.iterator();
 
         while (it1.hasNext() && it2.hasNext() && partsEqual(it1, it2))
         {
             if (it1.isAttribute())
             {
                 result.appendAttribute(it1.currentKey());
             }
             else
             {
                 result.append(it1.currentKey());
                 if (it1.hasIndex)
                 {
                     result.appendIndex(it1.getIndex());
                 }
             }
         }
 
         return result;
     }
 
     /**
      * Returns the &quot;difference key&quot; to a given key. This value
      * is the part of the passed in key that differs from this key. There is
      * the following relation:
      * <code>other = key.commonKey(other) + key.differenceKey(other)</code>
      * for an arbitrary configuration key <code>key</code>.
      *
      * @param other the key for which the difference is to be calculated
      * @return the difference key
      */
     public ConfigurationKey differenceKey(ConfigurationKey other)
     {
         ConfigurationKey common = commonKey(other);
         ConfigurationKey result = new ConfigurationKey();
 
         if (common.length() < other.length())
         {
             String k = other.toString().substring(common.length());
             // skip trailing delimiters
             int i = 0;
             while (i < k.length() && k.charAt(i) == PROPERTY_DELIMITER)
             {
                 i++;
             }
 
             if (i < k.length())
             {
                 result.append(k.substring(i));
             }
         }
 
         return result;
     }
 
     /**
      * Helper method for comparing two key parts.
      *
      * @param it1 the iterator with the first part
      * @param it2 the iterator with the second part
      * @return a flag if both parts are equal
      */
     private static boolean partsEqual(KeyIterator it1, KeyIterator it2)
     {
         return it1.nextKey().equals(it2.nextKey())
         && it1.getIndex() == it2.getIndex()
         && it1.isAttribute() == it2.isAttribute();
     }
 
     /**
      * A specialized iterator class for tokenizing a configuration key.
      * This class implements the normal iterator interface. In addition it
      * provides some specific methods for configuration keys.
      */
     public class KeyIterator implements Iterator, Cloneable
     {
         /** Stores the current key name.*/
         private String current;
 
         /** Stores the start index of the actual token.*/
         private int startIndex;
 
         /** Stores the end index of the actual token.*/
         private int endIndex;
 
         /** Stores the index of the actual property if there is one.*/
         private int indexValue;
 
         /** Stores a flag if the actual property has an index.*/
         private boolean hasIndex;
 
         /** Stores a flag if the actual property is an attribute.*/
         private boolean attribute;
 
         /**
          * Helper method for determining the next indices.
          *
          * @return the next key part
          */
         private String findNextIndices()
         {
             startIndex = endIndex;
             // skip empty names
             while (startIndex < keyBuffer.length()
                     && keyBuffer.charAt(startIndex) == PROPERTY_DELIMITER)
             {
                 startIndex++;
             }
 
             // Key ends with a delimiter?
             if (startIndex >= keyBuffer.length())
             {
                 endIndex = keyBuffer.length();
                 startIndex = endIndex - 1;
                 return keyBuffer.substring(startIndex, endIndex);
             }
             else
             {
                 return nextKeyPart();
             }
         }
 
         /**
          * Helper method for extracting the next key part. Takes escaping of
          * delimiter characters into account.
          *
          * @return the next key part
          */
         private String nextKeyPart()
         {
             StringBuffer key = new StringBuffer(INITIAL_SIZE);
             int idx = startIndex;
             int endIdx = keyBuffer.toString().indexOf(ATTRIBUTE_START,
                     startIndex);
             if (endIdx < 0 || endIdx == startIndex)
             {
                 endIdx = keyBuffer.length();
             }
             boolean found = false;
 
             while (!found && idx < endIdx)
             {
                 char c = keyBuffer.charAt(idx);
                 if (c == PROPERTY_DELIMITER)
                 {
                     // a duplicated delimiter means escaping
                     if (idx == endIdx - 1
                             || keyBuffer.charAt(idx + 1) != PROPERTY_DELIMITER)
                     {
                         found = true;
                     }
                     else
                     {
                         idx++;
                     }
                 }
                 if (!found)
                 {
                     key.append(c);
                     idx++;
                 }
             }
 
             endIndex = idx;
             return key.toString();
         }
 
         /**
          * Returns the next key part of this configuration key. This is a short
          * form of <code>nextKey(false)</code>.
          *
          * @return the next key part
          */
         public String nextKey()
         {
             return nextKey(false);
         }
 
         /**
          * Returns the next key part of this configuration key. The boolean
          * parameter indicates wheter a decorated key should be returned. This
          * affects only attribute keys: if the parameter is <b>false</b>, the
          * attribute markers are stripped from the key; if it is <b>true</b>,
          * they remain.
          *
          * @param decorated a flag if the decorated key is to be returned
          * @return the next key part
          */
         public String nextKey(boolean decorated)
         {
             if (!hasNext())
             {
                 throw new NoSuchElementException("No more key parts!");
             }
 
             hasIndex = false;
             indexValue = -1;
             String key = findNextIndices();
 
             current = key;
             hasIndex = checkIndex(key);
             attribute = checkAttribute(current);
 
             return currentKey(decorated);
         }
 
         /**
          * Helper method for checking if the passed key is an attribute.
          * If this is the case, the internal fields will be set.
          *
          * @param key the key to be checked
          * @return a flag if the key is an attribute
          */
         private boolean checkAttribute(String key)
         {
             if (isAttributeKey(key))
             {
                 current = removeAttributeMarkers(key);
                 return true;
             }
             else
             {
                 return false;
             }
         }
 
         /**
          * Helper method for checking if the passed key contains an index.
          * If this is the case, internal fields will be set.
          *
          * @param key the key to be checked
          * @return a flag if an index is defined
          */
         private boolean checkIndex(String key)
         {
             boolean result = false;
 
             int idx = key.lastIndexOf(INDEX_START);
             if (idx > 0)
             {
                 int endidx = key.indexOf(INDEX_END, idx);
 
                 if (endidx > idx + 1)
                 {
                     indexValue = Integer.parseInt(key.substring(idx + 1, endidx));
                     current = key.substring(0, idx);
                     result = true;
                 }
             }
 
             return result;
         }
 
         /**
          * Checks if there is a next element.
          *
          * @return a flag if there is a next element
          */
         public boolean hasNext()
         {
             return endIndex < keyBuffer.length();
         }
 
         /**
          * Returns the next object in the iteration.
          *
          * @return the next object
          */
         public Object next()
         {
             return nextKey();
         }
 
         /**
          * Removes the current object in the iteration. This method is not
          * supported by this iterator type, so an exception is thrown.
          */
         public void remove()
         {
             throw new UnsupportedOperationException("Remove not supported!");
         }
 
         /**
          * Returns the current key of the iteration (without skipping to the
          * next element). This is the same key the previous <code>next()</code>
          * call had returned. (Short form of <code>currentKey(false)</code>.
          *
          * @return the current key
          */
         public String currentKey()
         {
             return currentKey(false);
         }
 
         /**
          * Returns the current key of the iteration (without skipping to the
          * next element). The boolean parameter indicates wheter a decorated
          * key should be returned. This affects only attribute keys: if the
          * parameter is <b>false</b>, the attribute markers are stripped from
          * the key; if it is <b>true</b>, they remain.
          *
          * @param decorated a flag if the decorated key is to be returned
          * @return the current key
          */
         public String currentKey(boolean decorated)
         {
             return (decorated && isAttribute()) ? constructAttributeKey(current) : current;
         }
 
         /**
          * Returns a flag if the current key is an attribute. This method can
          * be called after <code>next()</code>.
          *
          * @return a flag if the current key is an attribute
          */
         public boolean isAttribute()
         {
             return attribute;
         }
 
         /**
          * Returns the index value of the current key. If the current key does
          * not have an index, return value is -1. This method can be called
          * after <code>next()</code>.
          *
          * @return the index value of the current key
          */
         public int getIndex()
         {
             return indexValue;
         }
 
         /**
          * Returns a flag if the current key has an associated index.
          * This method can be called after <code>next()</code>.
          *
          * @return a flag if the current key has an index
          */
         public boolean hasIndex()
         {
             return hasIndex;
         }
 
         /**
          * Creates a clone of this object.
          *
          * @return a clone of this object
          */
         public Object clone()
         {
             try
             {
                 return super.clone();
             }
             catch (CloneNotSupportedException cex)
             {
                 // should not happen
                 return null;
             }
         }
     }
 }

1		/*
2		* Licensed to the Apache Software Foundation (ASF) under one or more
3		* contributor license agreements. See the NOTICE file distributed with
4		* this work for additional information regarding copyright ownership.
5		* The ASF licenses this file to You under the Apache License, Version 2.0
6		* (the "License"); you may not use this file except in compliance with
7		* the License. You may obtain a copy of the License at
8		*
9		* http://www.apache.org/licenses/LICENSE-2.0
10		*
11		* Unless required by applicable law or agreed to in writing, software
12		* distributed under the License is distributed on an "AS IS" BASIS,
13		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14		* See the License for the specific language governing permissions and
15		* limitations under the License.
16		*/
17
18		package org.apache.commons.configuration;
19
20		import java.io.Serializable;
21		import java.util.Iterator;
22		import java.util.NoSuchElementException;
23
24		/**
25		* <p>A simple class that supports creation of and iteration on complex
26		* configuration keys.</p>
27		*
28		* <p>For key creation the class works similar to a StringBuffer: There are
29		* several <code>appendXXXX()</code> methods with which single parts
30		* of a key can be constructed. All these methods return a reference to the
31		* actual object so they can be written in a chain. When using this methods
32		* the exact syntax for keys need not be known.</p>
33		*
34		* <p>This class also defines a specialized iterator for configuration keys.
35		* With such an iterator a key can be tokenized into its single parts. For
36		* each part it can be checked whether it has an associated index.</p>
37		*
38		* @author <a href="mailto:oliver.heger@t-online.de">Oliver Heger</a>
39		* @version $Id: ConfigurationKey.java 439648 2006-09-02 20:42:10Z oheger $
40		*/
41	9120	public class ConfigurationKey implements Serializable
42		{
43		/** Constant for a property delimiter.*/
44		public static final char PROPERTY_DELIMITER = '.';
45
46		/** Constant for an escaped delimiter. */
47	3	public static final String ESCAPED_DELIMITER =
48		String.valueOf(PROPERTY_DELIMITER) + String.valueOf(PROPERTY_DELIMITER);
49
50		/** Constant for an attribute start marker.*/
51		private static final String ATTRIBUTE_START = "[@";
52
53		/** Constant for an attribute end marker.*/
54		private static final String ATTRIBUTE_END = "]";
55
56		/** Constant for an index start marker.*/
57		private static final char INDEX_START = '(';
58
59		/** Constant for an index end marker.*/
60		private static final char INDEX_END = ')';
61
62		/** Constant for the initial StringBuffer size.*/
63		private static final int INITIAL_SIZE = 32;
64
65		/**
66		* The serial version ID.
67		*/
68		private static final long serialVersionUID = -4299732083605277656L;
69
70		/** Holds a buffer with the so far created key.*/
71		private StringBuffer keyBuffer;
72
73		/**
74		* Creates a new, empty instance of <code>ConfigurationKey</code>.
75		*/
76		public ConfigurationKey()
77	183	{
78	183	keyBuffer = new StringBuffer(INITIAL_SIZE);
79	183	}
80
81		/**
82		* Creates a new instance of <code>ConfigurationKey</code> and
83		* initializes it with the given key.
84		*
85		* @param key the key as a string
86		*/
87		public ConfigurationKey(String key)
88	54	{
89	54	keyBuffer = new StringBuffer(key);
90	54	removeTrailingDelimiter();
91	54	}
92
93		/**
94		* Appends the name of a property to this key. If necessary, a
95		* property delimiter will be added.
96		*
97		* @param property the name of the property to be added
98		* @return a reference to this object
99		*/
100		public ConfigurationKey append(String property)
101		{
102	257	if (keyBuffer.length() > 0 && !hasDelimiter() && !isAttributeKey(property))
103		{
104	108	keyBuffer.append(PROPERTY_DELIMITER);
105		}
106
107	257	keyBuffer.append(property);
108	257	removeTrailingDelimiter();
109	257	return this;
110		}
111
112		/**
113		* Appends an index to this configuration key.
114		*
115		* @param index the index to be appended
116		* @return a reference to this object
117		*/
118		public ConfigurationKey appendIndex(int index)
119		{
120	21	keyBuffer.append(INDEX_START).append(index);
121	21	keyBuffer.append(INDEX_END);
122	21	return this;
123		}
124
125		/**
126		* Appends an attribute to this configuration key.
127		*
128		* @param attr the name of the attribute to be appended
129		* @return a reference to this object
130		*/
131		public ConfigurationKey appendAttribute(String attr)
132		{
133	5	keyBuffer.append(constructAttributeKey(attr));
134	5	return this;
135		}
136
137		/**
138		* Checks if this key is an attribute key.
139		*
140		* @return a flag if this key is an attribute key
141		*/
142		public boolean isAttributeKey()
143		{
144	0	return isAttributeKey(keyBuffer.toString());
145		}
146
147		/**
148		* Checks if the passed in key is an attribute key. Such attribute keys
149		* start and end with certain marker strings. In some cases they must be
150		* treated slightly different.
151		*
152		* @param key the key (part) to be checked
153		* @return a flag if this key is an attribute key
154		*/
155		public static boolean isAttributeKey(String key)
156		{
157	681	return key != null
158		&& key.startsWith(ATTRIBUTE_START)
159		&& key.endsWith(ATTRIBUTE_END);
160		}
161
162		/**
163		* Decorates the given key so that it represents an attribute. Adds
164		* special start and end markers.
165		*
166		* @param key the key to be decorated
167		* @return the decorated attribute key
168		*/
169		public static String constructAttributeKey(String key)
170		{
171	8	StringBuffer buf = new StringBuffer();
172	8	buf.append(ATTRIBUTE_START).append(key).append(ATTRIBUTE_END);
173	8	return buf.toString();
174		}
175
176		/**
177		* Extracts the name of the attribute from the given attribute key.
178		* This method removes the attribute markers - if any - from the
179		* specified key.
180		*
181		* @param key the attribute key
182		* @return the name of the corresponding attribute
183		*/
184		public static String attributeName(String key)
185		{
186	2	return isAttributeKey(key) ? removeAttributeMarkers(key) : key;
187		}
188
189		/**
190		* Helper method for removing attribute markers from a key.
191		*
192		* @param key the key
193		* @return the key with removed attribute markers
194		*/
195		static String removeAttributeMarkers(String key)
196		{
197	7	return key.substring(ATTRIBUTE_START.length(), key.length() - ATTRIBUTE_END.length());
198		}
199
200		/**
201		* Helper method that checks if the actual buffer ends with a property
202		* delimiter.
203		*
204		* @return a flag if there is a trailing delimiter
205		*/
206		private boolean hasDelimiter()
207		{
208	424	int count = 0;
209	424	for (int idx = keyBuffer.length() - 1; idx >= 0
210	8	&& keyBuffer.charAt(idx) == PROPERTY_DELIMITER; idx--)
211		{
212	8	count++;
213		}
214	424	return count % 2 == 1;
215		}
216
217		/**
218		* Removes a trailing delimiter if there is any.
219		*/
220		private void removeTrailingDelimiter()
221		{
222	626	while (hasDelimiter())
223		{
224	4	keyBuffer.deleteCharAt(keyBuffer.length() - 1);
225		}
226	311	}
227
228		/**
229		* Returns a string representation of this object. This is the
230		* configuration key as a plain string.
231		*
232		* @return a string for this object
233		*/
234		public String toString()
235		{
236	121	return keyBuffer.toString();
237		}
238
239		/**
240		* Returns an iterator for iterating over the single components of
241		* this configuration key.
242		*
243		* @return an iterator for this key
244		*/
245		public KeyIterator iterator()
246		{
247	277	return new KeyIterator();
248		}
249
250		/**
251		* Returns the actual length of this configuration key.
252		*
253		* @return the length of this key
254		*/
255		public int length()
256		{
257	203	return keyBuffer.length();
258		}
259
260		/**
261		* Sets the new length of this configuration key. With this method it is
262		* possible to truncate the key, e.g. to return to a state prior calling
263		* some <code>append()</code> methods. The semantic is the same as
264		* the <code>setLength()</code> method of <code>StringBuffer</code>.
265		*
266		* @param len the new length of the key
267		*/
268		public void setLength(int len)
269		{
270	1	keyBuffer.setLength(len);
271	1	}
272
273		/**
274		* Checks if two <code>ConfigurationKey</code> objects are equal. The
275		* method can be called with strings or other objects, too.
276		*
277		* @param c the object to compare
278		* @return a flag if both objects are equal
279		*/
280		public boolean equals(Object c)
281		{
282	11	if (c == null)
283		{
284	1	return false;
285		}
286
287	10	return keyBuffer.toString().equals(c.toString());
288		}
289
290		/**
291		* Returns the hash code for this object.
292		*
293		* @return the hash code
294		*/
295		public int hashCode()
296		{
297	2	return String.valueOf(keyBuffer).hashCode();
298		}
299
300		/**
301		* Returns a configuration key object that is initialized with the part
302		* of the key that is common to this key and the passed in key.
303		*
304		* @param other the other key
305		* @return a key object with the common key part
306		*/
307		public ConfigurationKey commonKey(ConfigurationKey other)
308		{
309	104	if (other == null)
310		{
311	1	throw new IllegalArgumentException("Other key must no be null!");
312		}
313
314	103	ConfigurationKey result = new ConfigurationKey();
315	103	KeyIterator it1 = iterator();
316	103	KeyIterator it2 = other.iterator();
317
318	350	while (it1.hasNext() && it2.hasNext() && partsEqual(it1, it2))
319		{
320	144	if (it1.isAttribute())
321		{
322	2	result.appendAttribute(it1.currentKey());
323		}
324		else
325		{
326	142	result.append(it1.currentKey());
327	142	if (it1.hasIndex)
328		{
329	7	result.appendIndex(it1.getIndex());
330		}
331		}
332		}
333
334	103	return result;
335		}
336
337		/**
338		* Returns the "difference key" to a given key. This value
339		* is the part of the passed in key that differs from this key. There is
340		* the following relation:
341		* <code>other = key.commonKey(other) + key.differenceKey(other)</code>
342		* for an arbitrary configuration key <code>key</code>.
343		*
344		* @param other the key for which the difference is to be calculated
345		* @return the difference key
346		*/
347		public ConfigurationKey differenceKey(ConfigurationKey other)
348		{
349	67	ConfigurationKey common = commonKey(other);
350	67	ConfigurationKey result = new ConfigurationKey();
351
352	67	if (common.length() < other.length())
353		{
354	63	String k = other.toString().substring(common.length());
355		// skip trailing delimiters
356	63	int i = 0;
357	170	while (i < k.length() && k.charAt(i) == PROPERTY_DELIMITER)
358		{
359	44	i++;
360		}
361
362	63	if (i < k.length())
363		{
364	63	result.append(k.substring(i));
365		}
366		}
367
368	67	return result;
369		}
370
371		/**
372		* Helper method for comparing two key parts.
373		*
374		* @param it1 the iterator with the first part
375		* @param it2 the iterator with the second part
376		* @return a flag if both parts are equal
377		*/
378		private static boolean partsEqual(KeyIterator it1, KeyIterator it2)
379		{
380	232	return it1.nextKey().equals(it2.nextKey())
381		&& it1.getIndex() == it2.getIndex()
382		&& it1.isAttribute() == it2.isAttribute();
383		}
384
385		/**
386		* A specialized iterator class for tokenizing a configuration key.
387		* This class implements the normal iterator interface. In addition it
388		* provides some specific methods for configuration keys.
389		*/
390	419	public class KeyIterator implements Iterator, Cloneable
391		{
392		/** Stores the current key name.*/
393		private String current;
394
395		/** Stores the start index of the actual token.*/
396		private int startIndex;
397
398		/** Stores the end index of the actual token.*/
399		private int endIndex;
400
401		/** Stores the index of the actual property if there is one.*/
402		private int indexValue;
403
404		/** Stores a flag if the actual property has an index.*/
405		private boolean hasIndex;
406
407		/** Stores a flag if the actual property is an attribute.*/
408		private boolean attribute;
409
410		/**
411		* Helper method for determining the next indices.
412		*
413		* @return the next key part
414		*/
415		private String findNextIndices()
416		{
417	567	startIndex = endIndex;
418		// skip empty names
419	567	while (startIndex < keyBuffer.length()
420	883	&& keyBuffer.charAt(startIndex) == PROPERTY_DELIMITER)
421		{
422	316	startIndex++;
423		}
424
425		// Key ends with a delimiter?
426	567	if (startIndex >= keyBuffer.length())
427		{
428	0	endIndex = keyBuffer.length();
429	0	startIndex = endIndex - 1;
430	0	return keyBuffer.substring(startIndex, endIndex);
431		}
432		else
433		{
434	567	return nextKeyPart();
435		}
436		}
437
438		/**
439		* Helper method for extracting the next key part. Takes escaping of
440		* delimiter characters into account.
441		*
442		* @return the next key part
443		*/
444		private String nextKeyPart()
445		{
446	567	StringBuffer key = new StringBuffer(INITIAL_SIZE);
447	567	int idx = startIndex;
448	567	int endIdx = keyBuffer.toString().indexOf(ATTRIBUTE_START,
449		startIndex);
450	567	if (endIdx < 0 \|\| endIdx == startIndex)
451		{
452	532	endIdx = keyBuffer.length();
453		}
454	567	boolean found = false;
455
456	5254	while (!found && idx < endIdx)
457		{
458	4120	char c = keyBuffer.charAt(idx);
459	4120	if (c == PROPERTY_DELIMITER)
460		{
461		// a duplicated delimiter means escaping
462	385	if (idx == endIdx - 1
463		\|\| keyBuffer.charAt(idx + 1) != PROPERTY_DELIMITER)
464		{
465	382	found = true;
466		}
467		else
468		{
469	3	idx++;
470		}
471		}
472	4120	if (!found)
473		{
474	3738	key.append(c);
475	3738	idx++;
476		}
477		}
478
479	567	endIndex = idx;
480	567	return key.toString();
481		}
482
483		/**
484		* Returns the next key part of this configuration key. This is a short
485		* form of <code>nextKey(false)</code>.
486		*
487		* @return the next key part
488		*/
489		public String nextKey()
490		{
491	566	return nextKey(false);
492		}
493
494		/**
495		* Returns the next key part of this configuration key. The boolean
496		* parameter indicates wheter a decorated key should be returned. This
497		* affects only attribute keys: if the parameter is <b>false</b>, the
498		* attribute markers are stripped from the key; if it is <b>true</b>,
499		* they remain.
500		*
501		* @param decorated a flag if the decorated key is to be returned
502		* @return the next key part
503		*/
504		public String nextKey(boolean decorated)
505		{
506	568	if (!hasNext())
507		{
508	1	throw new NoSuchElementException("No more key parts!");
509		}
510
511	567	hasIndex = false;
512	567	indexValue = -1;
513	567	String key = findNextIndices();
514
515	567	current = key;
516	567	hasIndex = checkIndex(key);
517	567	attribute = checkAttribute(current);
518
519	567	return currentKey(decorated);
520		}
521
522		/**
523		* Helper method for checking if the passed key is an attribute.
524		* If this is the case, the internal fields will be set.
525		*
526		* @param key the key to be checked
527		* @return a flag if the key is an attribute
528		*/
529		private boolean checkAttribute(String key)
530		{
531	567	if (isAttributeKey(key))
532		{
533	6	current = removeAttributeMarkers(key);
534	6	return true;
535		}
536		else
537		{
538	561	return false;
539		}
540		}
541
542		/**
543		* Helper method for checking if the passed key contains an index.
544		* If this is the case, internal fields will be set.
545		*
546		* @param key the key to be checked
547		* @return a flag if an index is defined
548		*/
549		private boolean checkIndex(String key)
550		{
551	567	boolean result = false;
552
553	567	int idx = key.lastIndexOf(INDEX_START);
554	567	if (idx > 0)
555		{
556	23	int endidx = key.indexOf(INDEX_END, idx);
557
558	23	if (endidx > idx + 1)
559		{
560	22	indexValue = Integer.parseInt(key.substring(idx + 1, endidx));
561	22	current = key.substring(0, idx);
562	22	result = true;
563		}
564		}
565
566	567	return result;
567		}
568
569		/**
570		* Checks if there is a next element.
571		*
572		* @return a flag if there is a next element
573		*/
574		public boolean hasNext()
575		{
576	1183	return endIndex < keyBuffer.length();
577		}
578
579		/**
580		* Returns the next object in the iteration.
581		*
582		* @return the next object
583		*/
584		public Object next()
585		{
586	5	return nextKey();
587		}
588
589		/**
590		* Removes the current object in the iteration. This method is not
591		* supported by this iterator type, so an exception is thrown.
592		*/
593		public void remove()
594		{
595	1	throw new UnsupportedOperationException("Remove not supported!");
596		}
597
598		/**
599		* Returns the current key of the iteration (without skipping to the
600		* next element). This is the same key the previous <code>next()</code>
601		* call had returned. (Short form of <code>currentKey(false)</code>.
602		*
603		* @return the current key
604		*/
605		public String currentKey()
606		{
607	144	return currentKey(false);
608		}
609
610		/**
611		* Returns the current key of the iteration (without skipping to the
612		* next element). The boolean parameter indicates wheter a decorated
613		* key should be returned. This affects only attribute keys: if the
614		* parameter is <b>false</b>, the attribute markers are stripped from
615		* the key; if it is <b>true</b>, they remain.
616		*
617		* @param decorated a flag if the decorated key is to be returned
618		* @return the current key
619		*/
620		public String currentKey(boolean decorated)
621		{
622	775	return (decorated && isAttribute()) ? constructAttributeKey(current) : current;
623		}
624
625		/**
626		* Returns a flag if the current key is an attribute. This method can
627		* be called after <code>next()</code>.
628		*
629		* @return a flag if the current key is an attribute
630		*/
631		public boolean isAttribute()
632		{
633	499	return attribute;
634		}
635
636		/**
637		* Returns the index value of the current key. If the current key does
638		* not have an index, return value is -1. This method can be called
639		* after <code>next()</code>.
640		*
641		* @return the index value of the current key
642		*/
643		public int getIndex()
644		{
645	303	return indexValue;
646		}
647
648		/**
649		* Returns a flag if the current key has an associated index.
650		* This method can be called after <code>next()</code>.
651		*
652		* @return a flag if the current key has an index
653		*/
654		public boolean hasIndex()
655		{
656	5	return hasIndex;
657		}
658
659		/**
660		* Creates a clone of this object.
661		*
662		* @return a clone of this object
663		*/
664		public Object clone()
665		{
666		try
667		{
668	0	return super.clone();
669		}
670		catch (CloneNotSupportedException cex)
671		{
672		// should not happen
673	0	return null;
674		}
675		}
676		}
677		}