# ContentHandler

public interface **ContentHandler**

|---|---|---|
| Known Indirect Subclasses [DefaultHandler](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/DefaultHandler.html), [DefaultHandler2](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ext/DefaultHandler2.html), [TemplatesHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/transform/sax/TemplatesHandler.html), [TransformerHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/transform/sax/TransformerHandler.html), [ValidatorHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/validation/ValidatorHandler.html), [XMLFilterImpl](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/XMLFilterImpl.html), [XMLReaderAdapter](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/XMLReaderAdapter.html) |---|---| | [DefaultHandler](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/DefaultHandler.html) | Default base class for SAX2 event handlers. | | [DefaultHandler2](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ext/DefaultHandler2.html) | This class extends the SAX2 base handler class to support the SAX2 `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ext/LexicalHandler.html`, `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ext/DeclHandler.html`, and `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ext/EntityResolver2.html` extensions. | | [TemplatesHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/transform/sax/TemplatesHandler.html) | A SAX ContentHandler that may be used to process SAX parse events (parsing transformation instructions) into a Templates object. | | [TransformerHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/transform/sax/TransformerHandler.html) | A TransformerHandler listens for SAX ContentHandler parse events and transforms them to a Result. | | [ValidatorHandler](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/validation/ValidatorHandler.html) | Streaming validator that works on SAX stream. | | [XMLFilterImpl](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/XMLFilterImpl.html) | Base class for deriving an XML filter. | | [XMLReaderAdapter](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/XMLReaderAdapter.html) | Adapt a SAX2 XMLReader as a SAX1 Parser. | |||

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**.* See <http://www.saxproject.org> for further information.

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
the SAX parser using the `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/XMLReader.html#setContentHandler(org.xml.sax.ContentHandler)` method. The parser uses the instance to report
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
`ContentHandler` class in the `java.net`
package; that means that it's probably a bad idea to do

```
import java.net.*;
 import org.xml.sax.*;
 
```

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

<br />

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/XMLReader.html`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/DTDHandler.html`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ErrorHandler.html`

### Public Method Summary

|---|---|
| abstract void | [characters](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#characters(char[],%20int,%20int))(char\[\] ch, int start, int length) Receive notification of character data. |
| abstract void | [endDocument](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endDocument())() Receive notification of the end of a document. |
| abstract void | [endElement](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) uri, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) localName, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) qName) Receive notification of the end of an element. |
| abstract void | [endPrefixMapping](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endPrefixMapping(java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) prefix) End the scope of a prefix-URI mapping. |
| abstract void | [ignorableWhitespace](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#ignorableWhitespace(char[],%20int,%20int))(char\[\] ch, int start, int length) Receive notification of ignorable whitespace in element content. |
| abstract void | [processingInstruction](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#processingInstruction(java.lang.String,%20java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) target, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) data) Receive notification of a processing instruction. |
| abstract void | [setDocumentLocator](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#setDocumentLocator(org.xml.sax.Locator))([Locator](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Locator.html) locator) Receive an object for locating the origin of SAX document events. |
| abstract void | [skippedEntity](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#skippedEntity(java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) name) Receive notification of a skipped entity. |
| abstract void | [startDocument](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startDocument())() Receive notification of the beginning of a document. |
| abstract void | [startElement](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startElement(java.lang.String,%20java.lang.String,%20java.lang.String,%20org.xml.sax.Attributes))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) uri, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) localName, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) qName, [Attributes](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Attributes.html) atts) Receive notification of the beginning of an element. |
| abstract void | [startPrefixMapping](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startPrefixMapping(java.lang.String,%20java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) prefix, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) uri) Begin the scope of a prefix-URI Namespace mapping. |

## Public Methods

#### public abstract 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.

Individual characters may consist of more than one Java
`char` value. There are two important cases where this
happens, because characters can't be represented in just sixteen bits.
In one case, characters are represented in a *Surrogate Pair*,
using two special Unicode values. Such characters are in the so-called
"Astral Planes", with a code point above U+FFFF. A second case involves
composite characters, such as a base character combining with one or
more accent characters.

Your code should not assume that algorithms using
`char`-at-a-time idioms will be working in character
units; in some cases they will split characters. This is relevant
wherever XML permits arbitrary characters, such as attribute values,
processing instruction data, and comments as well as in data reported
from this method. It's also generally relevant whenever Java code
manipulates internationalized text; the issue isn't unique to XML.

Note that some parsers will report whitespace in element
content using the `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#ignorableWhitespace(char[],%20int,%20int)`
method rather than this one (validating parsers *must*
do so).

<br />

##### Parameters

| ch | the characters from the XML document |
| start | the start position in the array |
| length | the number of characters to read from the array |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#ignorableWhitespace(char[],%20int,%20int)`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Locator.html`

#### public abstract void
**endDocument**
()

Receive notification of the end of a document.

**There is an apparent contradiction between the
documentation for this method and the documentation for `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ErrorHandler.html#fatalError(org.xml.sax.SAXParseException)`. Until this ambiguity is
resolved in a future major release, clients should make no
assumptions about whether endDocument() will or will not be
invoked when the parser has reported a fatalError() or thrown
an exception.**

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.

<br />

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startDocument()`

#### public abstract void
**endElement**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) uri, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) localName, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) 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
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startElement(java.lang.String,%20java.lang.String,%20java.lang.String,%20org.xml.sax.Attributes)` event for every endElement
event (even when the element is empty).

For information on the names, see startElement.

<br />

##### 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 name (with prefix), or the empty string if qualified names are not available |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

#### public abstract void
**endPrefixMapping**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) prefix)

End the scope of a prefix-URI mapping.

See `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startPrefixMapping(java.lang.String,%20java.lang.String)` for
details. These events will always occur immediately after the
corresponding `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)` event, but the order of
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endPrefixMapping(java.lang.String)` events is not otherwise
guaranteed.

<br />

##### Parameters

| prefix | the prefix that was being mapped. This is the empty string when a default mapping scope ends. |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | the client may throw an exception during processing |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startPrefixMapping(java.lang.String,%20java.lang.String)`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)`

#### public abstract 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.

<br />

##### Parameters

| ch | the characters from the XML document |
| start | the start position in the array |
| length | the number of characters to read from the array |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#characters(char[],%20int,%20int)`

#### public abstract void
**processingInstruction**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) target, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) 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.

Like `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#characters(char[],%20int,%20int)`, processing instruction
data may have characters that need more than one `char`
value.

<br />

##### Parameters

| target | the processing instruction target |
| data | the processing instruction data, or null if none was supplied. The data does not include any whitespace separating it from the target |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

#### public abstract void
**setDocumentLocator**
([Locator](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Locator.html) locator)

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 SAX event callbacks after
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startDocument()` returns and before
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endDocument()` is called. The
application should not attempt to use it at any other time.

<br />

##### Parameters

| locator | an object that can return the location of any SAX document event |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Locator.html`

#### public abstract void
**skippedEntity**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) name)

Receive notification of a skipped entity.
This is not called for entity references within markup constructs
such as element start tags or markup declarations. (The XML
recommendation requires reporting skipped external entities.
SAX also reports internal entity expansion/non-expansion, except
within markup constructs.)

The Parser will invoke this method each time the entity is
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
`http://xml.org/sax/features/external-general-entities`
and the
`http://xml.org/sax/features/external-parameter-entities`
properties.

<br />

##### 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 "\[dtd\]" |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

#### public abstract void
**startDocument**
()

Receive notification of the beginning of a document.

The SAX parser will invoke this method only once, before any
other event callbacks (except for `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#setDocumentLocator(org.xml.sax.Locator)`).

<br />

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endDocument()`

#### public abstract void
**startElement**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) uri, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) localName, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) qName, [Attributes](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Attributes.html) atts)

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
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)` event for every startElement event
(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
values of the <var translate="no">http://xml.org/sax/features/namespaces</var>
and the <var translate="no">http://xml.org/sax/features/namespace-prefixes</var>
properties:

- the Namespace URI and local name are required when the namespaces property is <var translate="no">true</var> (the default), and are optional when the namespaces property is <var translate="no">false</var> (if one is specified, both must be);
- the qualified name is required when the namespace-prefixes property is <var translate="no">true</var>, and is optional when the namespace-prefixes property is <var translate="no">false</var> (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
(xmlns\* attributes) only if the
`http://xml.org/sax/features/namespace-prefixes`
property is true (it is false by default, and support for a
true value is optional).

Like `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#characters(char[],%20int,%20int)`, attribute values may have
characters that need more than one `char` value.

<br />

##### 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 Attributes object. The value of this object after startElement returns is undefined |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | any SAX exception, possibly wrapping another exception |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/Attributes.html`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/helpers/AttributesImpl.html`

#### public abstract void
**startPrefixMapping**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) prefix, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) 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
names when the `http://xml.org/sax/features/namespaces`
feature is <var translate="no">true</var> (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 immediately before the
corresponding `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startElement(java.lang.String,%20java.lang.String,%20java.lang.String,%20org.xml.sax.Attributes)` event,
and all `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endPrefixMapping(java.lang.String)`
events will occur immediately after the corresponding
`https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)` event,
but their order is not otherwise
guaranteed.

There should never be start/endPrefixMapping events for the
"xml" prefix, since it is predeclared and immutable.

<br />

##### Parameters

| prefix | the Namespace prefix being declared. An empty string is used for the default element namespace, which has no prefix. |
| uri | the Namespace URI the prefix is mapped to |
|---|---|

##### Throws

| [SAXException](https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/SAXException.html) | the client may throw an exception during processing |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#endPrefixMapping(java.lang.String)`
- `https://developers.google.com/j2objc/javadoc/jre/reference/org/xml/sax/ContentHandler.html#startElement(java.lang.String,%20java.lang.String,%20java.lang.String,%20org.xml.sax.Attributes)`