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Xerces 3.1.1 API: Interface ContentHandler
Xerces 3.1.1


Interface ContentHandler


public interface ContentHandler

Receive notification of the logical content of a document.

This module, both source code and documentation, is in the Public Domain, and comes with NO WARRANTY.

This is the main interface that most SAX applications implement: if the application needs to be informed of basic parsing events, it implements this interface and registers an instance with basic document-related events like the start and end of elements and character data.

The order of events in this interface is very important, and mirrors the order of information in the document itself. For example, all of an element's content (character data, processing instructions, and/or subelements) will appear, in order, between the startElement event and the corresponding endElement event.

This interface is similar to the now-deprecated SAX 1.0 DocumentHandler interface, but it adds support for Namespaces and for reporting skipped entities (in non-validating XML processors).

Implementors should note that there is also a Java class ContentHandler in the java.net package; that means that it's probably a bad idea to do

import java.net.*;

In fact, "import ...*" is usually a sign of sloppy programming anyway, so the user should consider this a feature rather than a bug.

Since:
SAX 2.0
Version:
2.0

int start, int length)
          Receive notification of character data.
          Receive notification of the end of a document. java.lang.String localName, java.lang.String qName)
          Receive notification of the end of an element.
          End the scope of a prefix-URI mapping. int start, int length)
          Receive notification of ignorable whitespace in element content. java.lang.String data)
          Receive notification of a processing instruction.
          Receive an object for locating the origin of SAX document events.
          Receive notification of a skipped entity.
          Receive notification of the beginning of a document. java.lang.String localName, java.lang.String qName,
          Receive notification of the beginning of an element. java.lang.String uri)
          Begin the scope of a prefix-URI Namespace mapping.
Method Summary
 void
 void
 void
 void
 void
 void
 void
 void
 void
 void
 void
 

Method Detail
setDocumentLocator

Receive an object for locating the origin of SAX document events.

SAX parsers are strongly encouraged (though not absolutely required) to supply a locator: if it does so, it must supply the locator to the application by invoking this method before invoking any of the other methods in the ContentHandler interface.

The locator allows the application to determine the end position of any document-related event, even if the parser is not reporting an error. Typically, the application will use this information for reporting its own errors (such as character content that does not match an application's business rules). The information returned by the locator is probably not sufficient for use with a search engine.

Note that the locator will return correct information only during the invocation of the events in this interface. The application should not attempt to use it at any other time.

Parameters:
locator - An object that can return the location of

startDocument

public void startDocument()
Receive notification of the beginning of a document.

The SAX parser will invoke this method only once, before any


endDocument

public void endDocument()
Receive notification of the end of a document.

The SAX parser will invoke this method only once, and it will be the last method invoked during the parse. The parser shall not invoke this method until it has either abandoned parsing (because of an unrecoverable error) or reached the end of input.


startPrefixMapping

public void startPrefixMapping(java.lang.String prefix,
                               java.lang.String uri)
Begin the scope of a prefix-URI Namespace mapping.

The information from this event is not necessary for normal Namespace processing: the SAX XML reader will automatically replace prefixes for element and attribute feature is true (the default).

There are cases, however, when applications need to use prefixes in character data or in attribute values, where they cannot safely be expanded automatically; the start/endPrefixMapping event supplies the information to the application to expand prefixes in those contexts itself, if necessary.

Note that start/endPrefixMapping events are not guaranteed to be properly nested relative to each-other: all startPrefixMapping events will occur before the guaranteed.

There should never be start/endPrefixMapping events for the


endPrefixMapping

public void endPrefixMapping(java.lang.String prefix)
End the scope of a prefix-URI mapping. details. This event will always occur after the corresponding guaranteed.


startElement
public void startElement(java.lang.String namespaceURI,
                         java.lang.String localName,
                         java.lang.String qName,
Receive notification of the beginning of an element.

The Parser will invoke this method at the beginning of every element in the XML document; there will be a corresponding (even when the element is empty). All of the element's content will be reported, in order, before the corresponding endElement event.

This event allows up to three name components for each element:

  1. the Namespace URI;
  2. the local name; and
  3. the qualified (prefixed) name.

Any or all of these may be provided, depending on the properties:

  • the Namespace URI and local name are required when the namespaces property is true (the default), and are optional when the namespaces property is false (if one is specified, both must be);
  • the qualified name is required when the namespace-prefixes property is true, and is optional when the namespace-prefixes property is false (the default).

Note that the attribute list provided will contain only attributes with explicit values (specified or defaulted): #IMPLIED attributes will be omitted. The attribute list will contain attributes used for Namespace declarations property is true (it is false by default, and support for a true value is optional).

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

endElement

public void endElement(java.lang.String namespaceURI,
                       java.lang.String localName,
                       java.lang.String qName)
Receive notification of the end of an element.

The SAX parser will invoke this method at the end of every element in the XML document; there will be a corresponding event (even when the element is empty).

For information on the names, see startElement.

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 XML 1.0 name (with prefix), or the wrapping another exception.

characters

public void characters(char[] ch,
                       int start,
                       int length)
Receive notification of character data.

The Parser will call this method to report each chunk of character data. SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.

Note that some parsers will report whitespace in element method rather than this one (validating parsers must do so).


ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)
Receive notification of ignorable whitespace in element content.

Validating Parsers must use this method to report each chunk of whitespace in element content (see the W3C XML 1.0 recommendation, section 2.10): non-validating parsers may also use this method if they are capable of parsing and using content models.

SAX parsers may return all contiguous whitespace in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity, so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.


processingInstruction

public void processingInstruction(java.lang.String target,
                                  java.lang.String data)
Receive notification of a processing instruction.

The Parser will invoke this method once for each processing instruction found: note that processing instructions may occur before or after the main document element.

A SAX parser must never report an XML declaration (XML 1.0, section 2.8) or a text declaration (XML 1.0, section 4.3.1) using this method.

Parameters:
target - The processing instruction target.
data - The processing instruction data, or null if none was supplied. The data does not include any wrapping another exception.

skippedEntity

public void skippedEntity(java.lang.String name)
Receive notification of a skipped entity.

The Parser will invoke this method once for each entity skipped. Non-validating processors may skip entities if they have not seen the declarations (because, for example, the entity was declared in an external DTD subset). All processors may skip external entities, depending on the values of the and the properties.

Parameters:
name - The name of the skipped entity. If it is a parameter entity, the name will begin with '%', and if it is the external DTD subset, it will be the string wrapping another exception.

Xerces 3.1.1