git.gag.com Git - debian/openrocket/blob - src/net/sf/openrocket/file/simplesax/DelegatorHandler.java

   1 package net.sf.openrocket.file.simplesax;
   2
   3 import java.util.HashMap;
   4 import java.util.Stack;
   5
   6 import net.sf.openrocket.aerodynamics.Warning;
   7 import net.sf.openrocket.aerodynamics.WarningSet;
   8
   9 import org.xml.sax.Attributes;
  10 import org.xml.sax.SAXException;
  11 import org.xml.sax.helpers.DefaultHandler;
  12
  13 /**
  14  * The actual handler class.  Contains the necessary methods for parsing the SAX source.
  15  * Delegates the actual content parsing to {@link ElementHandler} objects.
  16  */
  17 class DelegatorHandler extends DefaultHandler {
  18         private final WarningSet warnings;
  19
  20         private final Stack<ElementHandler> handlerStack = new Stack<ElementHandler>();
  21         private final Stack<StringBuilder> elementData = new Stack<StringBuilder>();
  22         private final Stack<HashMap<String, String>> elementAttributes =
  23                 new Stack<HashMap<String, String>>();
  24
  25
  26         // Ignore all elements as long as ignore > 0
  27         private int ignore = 0;
  28
  29
  30         public DelegatorHandler(ElementHandler initialHandler, WarningSet warnings) {
  31                 this.warnings = warnings;
  32                 handlerStack.add(initialHandler);
  33                 elementData.add(new StringBuilder()); // Just in case
  34         }
  35
  36
  37         /////////  SAX handlers
  38
  39         @Override
  40         public void startElement(String uri, String localName, String name,
  41                         Attributes attributes) throws SAXException {
  42
  43                 // Check for ignore
  44                 if (ignore > 0) {
  45                         ignore++;
  46                         return;
  47                 }
  48
  49                 // Check for unknown namespace
  50                 if (!uri.equals("")) {
  51                         warnings.add(Warning.fromString("Unknown namespace element '" + uri
  52                                         + "' encountered, ignoring."));
  53                         ignore++;
  54                         return;
  55                 }
  56
  57                 // Add layer to data stacks
  58                 elementData.push(new StringBuilder());
  59                 elementAttributes.push(copyAttributes(attributes));
  60
  61                 // Call the handler
  62                 ElementHandler h = handlerStack.peek();
  63                 h = h.openElement(localName, elementAttributes.peek(), warnings);
  64                 if (h != null) {
  65                         handlerStack.push(h);
  66                 } else {
  67                         // Start ignoring elements
  68                         ignore++;
  69                 }
  70         }
  71
  72
  73         /**
  74          * Stores encountered characters in the elementData stack.
  75          */
  76         @Override
  77         public void characters(char[] chars, int start, int length) throws SAXException {
  78                 // Check for ignore
  79                 if (ignore > 0)
  80                         return;
  81
  82                 StringBuilder sb = elementData.peek();
  83                 sb.append(chars, start, length);
  84         }
  85
  86
  87         /**
  88          * Removes the last layer from the stack.
  89          */
  90         @Override
  91         public void endElement(String uri, String localName, String name) throws SAXException {
  92
  93                 // Check for ignore
  94                 if (ignore > 0) {
  95                         ignore--;
  96                         return;
  97                 }
  98
  99                 // Remove data from stack
 100                 String data = elementData.pop().toString(); // throws on error
 101                 HashMap<String, String> attr = elementAttributes.pop();
 102
 103                 // Remove last handler and call the next one
 104                 ElementHandler h;
 105
 106                 h = handlerStack.pop();
 107                 h.endHandler(localName, attr, data, warnings);
 108
 109                 h = handlerStack.peek();
 110                 h.closeElement(localName, attr, data, warnings);
 111         }
 112
 113
 114         private static HashMap<String, String> copyAttributes(Attributes atts) {
 115                 HashMap<String, String> ret = new HashMap<String, String>();
 116                 for (int i = 0; i < atts.getLength(); i++) {
 117                         ret.put(atts.getLocalName(i), atts.getValue(i));
 118                 }
 119                 return ret;
 120         }
 121 }
 122