1    package classUtils.pack.util.xml.configuration; 
2     
3    import org.xml.sax.SAXException; 
4    import org.xml.sax.helpers.DefaultHandler; 
5     
6    /** 
7     * A base {@link Configurator Configurator}. 
8     * <p> 
9     * This class extends SAX's <tt>DefaultHandler</tt> and provides support 
10    * for: 
11    * <p> 
12    * <ul> 
13    * <li> collecting text (via the {@link #characters(char[], int, int)  
14    *      characters()} method); 
15    * <li> ensuring that {@link #getConfiguredObject() getConfiguredObject()} 
16    *      throws an exception if parsing hasn't completed yet (via the 
17    *      {@link #checkCompleted() checkCompleted()} method). 
18    * </ul> 
19    * <p> 
20    * Subclasses which override {@link #endElement(java.lang.String,  
21    * java.lang.String, java.lang.String) endElement()} should either invoke 
22    * this class' implementation or set to <b>true</b> the protected  
23    * <b>{@link #completed completed}</b> field when the configured object 
24    * is complete. 
25    *  
26    * @author Cristiano Sadun 
27    */ 
28   public abstract class BaseConfigurator extends DefaultHandler implements Configurator { 
29    
30       /** 
31        * The buffer collecting text received by {@link #characters(char[], int, int)  
32        * characters()}. 
33        */ 
34       protected StringBuffer buffer; 
35        
36       /** 
37        * Indicate that the object built from the XML is ready. 
38        */ 
39       protected boolean completed; 
40    
41       /** 
42        * Constructor for BaseConfigurator. 
43        */ 
44       public BaseConfigurator() { 
45           this.buffer = new StringBuffer(); 
46           this.completed = false; 
47       } 
48    
49       /** 
50        * Set {@link #completed completed} to true. 
51        *  
52        * 
53        */ 
54       public void endElement( 
55           String namespaceURI, 
56           String localName, 
57           String qName) { 
58           completed = true; 
59       } 
60    
61       /** 
62        * @see Configurator#getConfiguredObject() 
63        */ 
64       public final Object getConfiguredObject() { 
65           checkCompleted(); 
66           return doGetConfiguredObject(); 
67       } 
68    
69       /** 
70        * Throw an IllegalStateException if {@link #completed completed} is not <b>true</b>. 
71        */ 
72       protected void checkCompleted() { 
73           if (!completed) 
74               throw new IllegalStateException("The object(s) under configuration are not completed yet (possibly endElement has been overriden without invoking its super implementation)"); 
75       } 
76    
77       protected abstract Object doGetConfiguredObject(); 
78    
79       /** 
80        * @see Configurator#characters(char[], int, int) 
81        */ 
82       public void characters(char[] ch, int start, int length) 
83           throws SAXException { 
84           buffer.append(ch, start, length); 
85       } 
86    
87       /** 
88        * Returns the completed. 
89        * @return boolean 
90        */ 
91       public boolean isCompleted() { 
92           return completed; 
93       } 
94    
95       /** 
96        * @see Configurator#getText() 
97        */ 
98       public final String getText() { 
99           return buffer.toString(); 
100      } 
101   
102  } 
103