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

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