eu.ehri.project.importers.base

Class SaxXmlHandler

java.lang.Object

org.xml.sax.helpers.DefaultHandler

eu.ehri.project.importers.base.SaxXmlHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler, LexicalHandler

Direct Known Subclasses:

DcEuropeanaHandler, EacHandler, EadHandler, EagHandler, VirtualEadHandler

public abstract class SaxXmlHandler
extends org.xml.sax.helpers.DefaultHandler
implements LexicalHandler, ContentHandler

Reader of XML files, creator of Map-based representations of EA* files. Makes use of properties file with format:

path/within/xml/=node/property

if no <node> is given, it is the default logical-unit or unit-description of this property file. with eac.properties this would be an HistoricalAgent with an HistoricalAgentDescription if there is a <node> given, it will translate to another graph node, like Address.

lines starting with '@' give the attributes: @attribute=tmpname path/within/xml/@tmpname=node/property

all tags not included in the properties file that have a nodevalue will be put in a unknownproperties node, with an edge to the unit-description.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	currentEntity
protected Stack<Map<String,Object>>	currentGraphPath Key in the node that denotes the object's identifier.
protected Stack<String>	currentPath
protected Stack<StringBuilder>	currentText
protected int	depth
protected ItemImporter<Map<String,Object>,?>	importer
protected Map<String,Map<String,Object>>	languageMap
protected Locator	locator
protected XmlImportProperties	properties

Constructor Summary

Constructors

Constructor and Description
SaxXmlHandler(ItemImporter<Map<String,Object>,?> importer)
SaxXmlHandler(ItemImporter<Map<String,Object>,?> importer, XmlImportProperties properties)

Method Summary

Modifier and Type	Method and Description
void	characters(char[] ch, int start, int length) Receives character data in SAX events, converts multiple space to a single space and puts the characters in the current node, unless the input contains only whitespace.
void	comment(char[] ch, int start, int end)
void	endCDATA()
void	endDTD()
void	endElement(String uri, String localName, String qName) Receive an end element.
void	endEntity(String name)
protected String	getMappedProperty(Stack<String> path) Get the property name corresponding to the given path from the .properties file.
protected abstract boolean	needToCreateSubNode(String qName) Determines whether a new node that is a 'child' of the current node (i.e.
protected void	overwritePropertyInCurrentGraph(String property, String value) Overwrite a value in the current graph.
protected void	printGraph() Print a text representation of the graph on `System.out`.
protected void	putPropertyInCurrentGraph(String property, String value) Stores this property value pair in the current DocumentNode.
protected void	putSubGraphInCurrentGraph(String key, Map<String,Object> subgraph) Insert a graph representation in the current graph (the one on top of the currentGraphPath stack) as a list item at the given key.
void	setDocumentLocator(Locator locator)
void	startCDATA()
void	startDTD(String name, String publicId, String systemId)
void	startElement(String uri, String localName, String qName, Attributes attributes) Receive an opening tag.
void	startEntity(String name)

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

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.xml.sax.ContentHandler

endDocument, endPrefixMapping, ignorableWhitespace, processingInstruction, skippedEntity, startDocument, startPrefixMapping

Field Detail

locator

protected Locator locator

currentGraphPath

protected final Stack<Map<String,Object>> currentGraphPath

Key in the node that denotes the object's identifier.

languageMap

protected final Map<String,Map<String,Object>> languageMap

currentPath

protected final Stack<String> currentPath

currentText

protected final Stack<StringBuilder> currentText

currentEntity

protected String currentEntity

importer

protected final ItemImporter<Map<String,Object>,?> importer

properties

protected final XmlImportProperties properties

depth

protected int depth

Constructor Detail

SaxXmlHandler

public SaxXmlHandler(ItemImporter<Map<String,Object>,?> importer)

SaxXmlHandler

public SaxXmlHandler(ItemImporter<Map<String,Object>,?> importer,
                     XmlImportProperties properties)

Method Detail

needToCreateSubNode

protected abstract boolean needToCreateSubNode(String qName)

Determines whether a new node that is a 'child' of the current node (i.e. a 'sub-node') needs to be created, based on the qualified element name.

Parameters:

qName - the QName

Returns:

true if the QName warrants a sub-node, false otherwise

startEntity

public void startEntity(String name)

Specified by:

startEntity in interface LexicalHandler

endEntity

public void endEntity(String name)

Specified by:

endEntity in interface LexicalHandler

startDTD

public void startDTD(String name,
                     String publicId,
                     String systemId)

Specified by:

startDTD in interface LexicalHandler

setDocumentLocator

public void setDocumentLocator(Locator locator)

Specified by:

setDocumentLocator in interface ContentHandler

Overrides:

setDocumentLocator in class org.xml.sax.helpers.DefaultHandler

endDTD

public void endDTD()

Specified by:

endDTD in interface LexicalHandler

comment

public void comment(char[] ch,
                    int start,
                    int end)

Specified by:

comment in interface LexicalHandler

startCDATA

public void startCDATA()

Specified by:

startCDATA in interface LexicalHandler

endCDATA

public void endCDATA()

Specified by:

endCDATA in interface LexicalHandler

startElement

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

Receive an opening tag. Initialise the current text to store the characters, create a language map to hold descriptions in different languages, push the level if this element warrants a new sub-node and store the attributes that need to be stored.

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

endElement

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

Receive an end element. Put the contents of the text holding space in the current graph as a property using the .properties file as a mapping.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

putSubGraphInCurrentGraph

protected void putSubGraphInCurrentGraph(String key,
                                         Map<String,Object> subgraph)

Insert a graph representation in the current graph (the one on top of the currentGraphPath stack) as a list item at the given key. The value stored at the key is always a list - if the key did not exist yet, a new list is created to which the sub-graph is added.

Parameters:

key - name of the edge to connect the sub-graph to the current graph

subgraph - Map graph representation to insert into the current graph

characters

public void characters(char[] ch,
                       int start,
                       int length)
                throws SAXException

Receives character data in SAX events, converts multiple space to a single space and puts the characters in the current node, unless the input contains only whitespace.

Specified by:

characters in interface ContentHandler

Overrides:

characters in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

putPropertyInCurrentGraph

protected void putPropertyInCurrentGraph(String property,
                                         String value)

Stores this property value pair in the current DocumentNode. If the property already exists, it is added to the value list.

Parameters:

property - the property name

value - the property value

overwritePropertyInCurrentGraph

protected void overwritePropertyInCurrentGraph(String property,
                                               String value)

Overwrite a value in the current graph.

Parameters:

property - name of the property to overwrite

value - new value for the property.

getMappedProperty

protected String getMappedProperty(Stack<String> path)

Get the property name corresponding to the given path from the .properties file.

Parameters:

path - the stacked element names forming a path from the root to the current element

Returns:

the corresponding value to this path from the properties file. the search is inside out, so if both eadheader/ and ead/eadheader/ are specified, it will return the value for the first

if this path has no corresponding value in the properties file, it will return the entire path name, with _ replacing the /

printGraph

protected void printGraph()

Print a text representation of the graph on `System.out`.