Class MapDBHandler

java.lang.Object

org.xml.sax.helpers.DefaultHandler

MapDBHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

public class MapDBHandler
extends DefaultHandler

Parses OSM XML files using an XML SAX parser. Used to construct the graph of roads for pathfinding, under some constraints. See OSM documentation on the highway tag, the way XML element, the node XML element, and the java SAX parser tutorial.

Author:

Alan Yao

Field Summary

Fields

Modifier and Type	Field and Description
private String	activeState
private static Set<String>	ALLOWED_HIGHWAY_TYPES Only allow for non-service roads; this prevents going on pedestrian streets as much as possible.
private GraphDB	g

Constructor Summary

Constructors

Constructor and Description
MapDBHandler(GraphDB g)

Method Summary

Modifier and Type	Method and Description
void	endElement(String uri, String localName, String qName) Receive notification of the end of an element.
void	startElement(String uri, String localName, String qName, Attributes attributes) Called at the beginning of an element.

Methods inherited from class org.xml.sax.helpers.DefaultHandler

characters, endDocument, endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, resolveEntity, setDocumentLocator, skippedEntity, startDocument, startPrefixMapping, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ALLOWED_HIGHWAY_TYPES

private static final Set<String> ALLOWED_HIGHWAY_TYPES

Only allow for non-service roads; this prevents going on pedestrian streets as much as possible. Note that in Berkeley, many of the campus roads are tagged as motor vehicle roads, but in practice we walk all over them with such impunity that we forget cars can actually drive on them.

activeState

private String activeState

g

private final GraphDB g

Constructor Detail

MapDBHandler

public MapDBHandler(GraphDB g)

Method Detail

startElement

public void startElement(String uri,
                         String localName,
                         String qName,
                         Attributes attributes)
                  throws SAXException

Called at the beginning of an element. Typically, you will want to handle each element in here, and you may want to track the parent element.

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class DefaultHandler

Parameters:

uri - The Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed.

localName - The local name (without prefix), or the empty string if Namespace processing is not being performed.

qName - The qualified name (with prefix), or the empty string if qualified names are not available. This tells us which element we're looking at.

attributes - The attributes attached to the element. If there are no attributes, it shall be an empty Attributes object.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

Attributes

endElement

public void endElement(String uri,
                       String localName,
                       String qName)
                throws SAXException

Receive notification of the end of an element. You may want to take specific terminating actions here, like finalizing vertices or edges found.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class DefaultHandler

Parameters:

uri - The Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed.

localName - The local name (without prefix), or the empty string if Namespace processing is not being performed.

qName - The qualified name (with prefix), or the empty string if qualified names are not available.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.