XMLStreamReader (JOSH API Document)

All Superinterfaces:: XMLStreamConstants

public interface XMLStreamReader
extends XMLStreamConstants

The XMLStreamReader interface allows forward, read-only access to XML. It is designed to be the lowest level and most efficient way to read XML data.

The XMLStreamReader is designed to iterate over XML using next() and hasNext(). The data can be accessed using methods such as getEventType(), getNamespaceURI(), getLocalName() and getText();

The next() method causes the reader to read the next parse event. The next() method returns an integer which identifies the type of event just read.

The event type can be determined using getEventType().

Parsing events are defined as the XML Declaration, a DTD, start tag, character data, white space, end tag, comment, or processing instruction. An attribute or namespace event may be encountered at the root level of a document as the result of a query operation.

For XML 1.0 compliance an XML processor must pass the identifiers of declared unparsed entities, notation declarations and their associated identifiers to the application. This information was provided through the property API on this interface. The following two properties allowed access to this information: "javax.xml.stream.notations" and "javax.xml.stream.entities". These properties are not supported in the JSR 280 subset of StAX; calls to getProperty("javax.xml.stream.notations"); or getProperty("javax.xml.stream.entities"); will always return null.

The following table describes which methods are valid in what state. If a method is called in an invalid state the method will throw a java.lang.IllegalStateException.

Valid methods for each state
Event Type	Valid Methods
All States	getProperty(), hasNext(), require(), close(), getNamespaceURI(), isWhiteSpace(), getEventType(),getLocation()
START_ELEMENT	next(), getLocalName(), getPrefix(), getAttributeXXX(), isAttributeSpecified(), getNamespaceXXX(), getElementText(), nextTag()
ATTRIBUTE	next(), nextTag() getAttributeXXX(), isAttributeSpecified()
NAMESPACE	next(), nextTag() getNamespaceXXX()
END_ELEMENT	next(), getLocalName(), getPrefix(), getNamespaceXXX(), nextTag()
CHARACTERS	next(), getTextXXX(), nextTag()
CDATA	next(), getTextXXX(), nextTag()
COMMENT	next(), getTextXXX(), nextTag()
SPACE	next(), getTextXXX(), nextTag()
START_DOCUMENT	next(), getEncoding(), getVersion(), isStandalone(), standaloneSet(), getCharacterEncodingScheme(), nextTag()
END_DOCUMENT	close()
PROCESSING_INSTRUCTION	next(), getPITarget(), getPIData(), nextTag()
ENTITY_REFERENCE	next(), getLocalName(), getText(), nextTag()
DTD	next(), getText(), nextTag()

See Also:: XMLInputFactory, XMLStreamWriter

Field Summary
- Fields inherited from interface javax.xml.stream.XMLStreamConstants
  ATTRIBUTE, CDATA, CHARACTERS, COMMENT, DTD, END_DOCUMENT, END_ELEMENT, ENTITY_DECLARATION, ENTITY_REFERENCE, NAMESPACE, NOTATION_DECLARATION, PROCESSING_INSTRUCTION, SPACE, START_DOCUMENT, START_ELEMENT

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Frees any resources associated with this Reader.
`int`	`getAttributeCount()` Returns the count of attributes on this START_ELEMENT, this method is only valid on a START_ELEMENT or ATTRIBUTE.
`String`	`getAttributeLocalName(int index)` Returns the localName of the attribute at the provided index
`String`	`getAttributeNamespace(int index)` Returns the namespace of the attribute at the provided index
`String`	`getAttributePrefix(int index)` Returns the prefix of this attribute at the provided index
`String`	`getAttributeType(int index)` Returns the XML type of the attribute at the provided index (see XML 1.0 Specification, section 3.3.1)
`String`	`getAttributeValue(int index)` Returns the value of the attribute at the index
`String`	`getAttributeValue(String namespaceURI, String localName)` Returns the normalized attribute value of the attribute with the namespace and localName.
`String`	`getCharacterEncodingScheme()` Returns the character encoding declared on the xml declaration Returns `null` if none was declared
`String`	`getElementText()` Reads the content of a text-only element, an exception is thrown if this is not a text-only element.
`String`	`getEncoding()` Return input encoding if known or `null` if unknown.
`int`	`getEventType()` Returns an integer code that indicates the type of the event the cursor is pointing to.
`String`	`getLocalName()` Returns the (local) name of the current event.
`Location`	`getLocation()` Return the current location of the processor.
`int`	`getNamespaceCount()` Returns the count of namespaces declared on this START_ELEMENT or END_ELEMENT, this method is only valid on a START_ELEMENT, END_ELEMENT or NAMESPACE.
`String`	`getNamespacePrefix(int index)` Returns the prefix for the namespace declared at the index.
`String`	`getNamespaceURI()` If the current event is a START_ELEMENT or END_ELEMENT this method returns the URI of the prefix or the default namespace.
`String`	`getNamespaceURI(int index)` Returns the uri for the namespace declared at the index.
`String`	`getNamespaceURI(String prefix)` Return the uri for the given prefix.
`String`	`getPIData()` Get the data section of a processing instruction
`String`	`getPITarget()` Get the target of a processing instruction
`String`	`getPrefix()` Returns the prefix of the current event or `null` if the event does not have a prefix
`Object`	`getProperty(String name)` Get the value of a feature/property from the underlying implementation
`String`	`getText()` Returns the current value of the parse event as a string, this returns the string value of a CHARACTERS event, returns the value of a COMMENT, the replacement value for an ENTITY_REFERENCE, the string value of a CDATA section, the string value for a SPACE event, or the String value of the internal subset of the DTD.
`char[]`	`getTextCharacters()` Returns an array which contains the characters from this event.
`int`	`getTextLength()` Returns the length of the sequence of characters for this Text event within the text character array.
`int`	`getTextStart()` Returns the offset into the text character array where the first character (of this text event) is stored.
`String`	`getVersion()` Get the xml version declared on the xml declaration.
`boolean`	`hasNext()` Returns `true` if there are more parsing events and `false` if there are no more events.
`boolean`	`isAttributeSpecified(int index)` Returns a boolean which indicates if this attribute was created by default
`boolean`	`isStandalone()` Get the standalone declaration from the xml declaration
`boolean`	`isWhiteSpace()` Returns `true` if the cursor points to a character data event that consists of all whitespace
`int`	`next()` Get next parsing event - a processor may return all contiguous character data in a single chunk, or it may split it into several chunks.
`int`	`nextTag()` Skips any white space (isWhiteSpace() returns `true`), COMMENT, or PROCESSING_INSTRUCTION, until a START_ELEMENT or END_ELEMENT is reached.
`void`	`require(int type, String namespaceURI, String localName)` Test if the current event is of the given type and if the namespace and name match the current namespace and name of the current event.
`boolean`	`standaloneSet()` Checks if standalone was set in the document

- Method Detail
  - getProperty
```
Object getProperty(String name)
                   throws IllegalArgumentException
```
    Get the value of a feature/property from the underlying implementation
    
    Parameters:
    name - The name of the property, may not be null
    
    Returns:
    The value of the property
    
    Throws:
    
    IllegalArgumentException - if name is null
  - next
```
int next()
         throws XMLStreamException
```
    Get next parsing event - a processor may return all contiguous character data in a single chunk, or it may split it into several chunks. If the property javax.xml.stream.isCoalescing is set to true element content must be coalesced and only one CHARACTERS event must be returned for contiguous element content or CDATA Sections. By default entity references must be expanded and reported transparently to the application. An exception will be thrown if an entity reference cannot be expanded. If element content is empty (i.e. content is "") then no CHARACTERS event will be reported.
    Given the following XML:
    <foo>content text<![CDATA[<greeting>Hello< /greeting>]]>other content</foo>
    The behavior of calling next() when being on foo will be:
    1- the comment (COMMENT)
    2- then the characters section (CHARACTERS)
    3- then the CDATA section (another CHARACTERS)
    4- then the next characters section (another CHARACTERS)
    5- then the END_ELEMENT
    
    NOTE: empty element (such as <tag/>) will be reported with two separate events: START_ELEMENT, END_ELEMENT - This preserves parsing equivalency of empty element to <tag></tag>.
    
    Returns:
    the integer code corresponding to the current parse event
    
    Throws:
    
    NoSuchElementException - if this is called when hasNext() returns false
    
    XMLStreamException - if there is an error processing the underlying XML source
  - require
```
void require(int type,
           String namespaceURI,
           String localName)
             throws XMLStreamException
```
    Test if the current event is of the given type and if the namespace and name match the current namespace and name of the current event. If the namespaceURI is null it is not checked for equality, if the localName is null it is not checked for equality.
    
    Parameters:
    type - the event type
    namespaceURI - the uri of the event, may be null
    localName - the localName of the event, may be null
    
    Throws:
    
    XMLStreamException - if the required values are not matched.
  - getElementText
```
String getElementText()
                      throws XMLStreamException
```
    Reads the content of a text-only element, an exception is thrown if this is not a text-only element. Regardless of value of javax.xml.stream.isCoalescing this method always returns coalesced content.
    Precondition: the current event is START_ELEMENT.
    Postcondition: the current event is the corresponding END_ELEMENT.
    The method does the following (implementations are free to optimize but must do equivalent processing):
```
 if(getEventType() != XMLStreamConstants.START_ELEMENT) {
     throw new XMLStreamException(
         "parser must be on START_ELEMENT to read next text", 
         getLocation());
 }
 int eventType = next();
 StringBuffer content = new StringBuffer();
 while(eventType != XMLStreamConstants.END_ELEMENT ) {
     if(eventType == XMLStreamConstants.CHARACTERS
             || eventType == XMLStreamConstants.CDATA
             || eventType == XMLStreamConstants.SPACE
             || eventType == XMLStreamConstants.ENTITY_REFERENCE) {
         buf.append(getText());
     } else if(eventType == XMLStreamConstants.PROCESSING_INSTRUCTION
             || eventType == XMLStreamConstants.COMMENT) {
             // skipping
     } else if(eventType == XMLStreamConstants.END_DOCUMENT) {
         throw new XMLStreamException(
             "unexpected end of document when reading element text content",
             this);
     } else if(eventType == XMLStreamConstants.START_ELEMENT) {
         throw new XMLStreamException(
             "element text content may not contain START_ELEMENT", 
             getLocation());
     } else {
         throw new XMLStreamException(
             "Unexpected event type "+eventType, getLocation());
     }
     eventType = next();
 }
 return buf.toString();
 
```
    Throws:
    
    XMLStreamException - if the current event is not a START_ELEMENT or if a non text element is encountered
  - nextTag
```
int nextTag()
            throws XMLStreamException
```
    Skips any white space (isWhiteSpace() returns true), COMMENT, or PROCESSING_INSTRUCTION, until a START_ELEMENT or END_ELEMENT is reached. If other than white space characters, COMMENT, PROCESSING_INSTRUCTION, START_ELEMENT, END_ELEMENT are encountered, an exception is thrown. This method should be used when processing element-only content separated by white space.
    Precondition: none
    Postcondition: the current event is START_ELEMENT or END_ELEMENT and cursor may have moved over any whitespace event.
    Essentially it does the following (implementations are free to optimize but must do equivalent processing):
```
 int eventType = next();
 // skip whitespace
 while((eventType == XMLStreamConstants.CHARACTERS 
         && isWhiteSpace())
         || (eventType == XMLStreamConstants.CDATA && isWhiteSpace()) 
         // skip whitespace
         || eventType == XMLStreamConstants.SPACE
         || eventType == XMLStreamConstants.PROCESSING_INSTRUCTION
         || eventType == XMLStreamConstants.COMMENT) {
     eventType = next();
 }
 if (eventType != XMLStreamConstants.START_ELEMENT 
         && eventType != XMLStreamConstants.END_ELEMENT) {
     throw new String XMLStreamException(
         "expected start or end tag", getLocation());
 }
 return eventType;
 
```
    Returns:
    the event type of the element read (START_ELEMENT or END_ELEMENT)
    
    Throws:
    
    XMLStreamException - if the current event is not white space, COMMENT, PROCESSING_INSTRUCTION, START_ELEMENT or END_ELEMENT
    
    NoSuchElementException - if this is called when hasNext() returns false
  - hasNext
```
boolean hasNext()
                throws XMLStreamException
```
    Returns true if there are more parsing events and false if there are no more events. This method will return false if the current state of the XMLStreamReader is END_DOCUMENT
    
    Returns:
    true if there are more events, false otherwise
    
    Throws:
    
    XMLStreamException - if there is a fatal error detecting the next state
  - close
```
void close()
           throws XMLStreamException
```
    Frees any resources associated with this Reader. This method does not close the underlying input source.
    
    Throws:
    
    XMLStreamException - if there are errors freeing associated resources
  - getNamespaceURI
```
String getNamespaceURI(String prefix)
```
    Return the uri for the given prefix. The uri returned depends on the current state of the processor.
    NOTE:The 'xml' prefix is bound as defined in Namespaces in XML specification to "http://www.w3.org/XML/1998/namespace".
    NOTE: The 'xmlns' prefix must be resolved to following namespace http://www.w3.org/2000/xmlns/
    
    Parameters:
    prefix - The prefix to lookup, may not be null
    
    Returns:
    the uri bound to the given prefix or null if it is not bound
    
    Throws:
    
    IllegalArgumentException - if the prefix is null
  - isWhiteSpace
```
boolean isWhiteSpace()
```
    Returns true if the cursor points to a character data event that consists of all whitespace
    
    Returns:
    true if the cursor points to all whitespace, false otherwise
  - getAttributeValue
```
String getAttributeValue(String namespaceURI,
                       String localName)
```
    Returns the normalized attribute value of the attribute with the namespace and localName. If the namespaceURI is null it is not checked for equality, i.e. only the localName part of an attribute name will be compared. A value of "" (empty String) is interpreted to mean 'no namespace', i.e. any matching attribute must have no namespace specified.
    
    Parameters:
    namespaceURI - the namespace of the attribute
    localName - the local name of the attribute, cannot be null
    
    Returns:
    returns the value of the attribute , returns null if not found
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
  - getAttributeCount
```
int getAttributeCount()
```
    Returns the count of attributes on this START_ELEMENT, this method is only valid on a START_ELEMENT or ATTRIBUTE. This count excludes namespace definitions when isNamespaceAware is true; when isNamespaceAware is false, the attribute count includes xmlns and xmlns.* attributes. Attribute indices are zero-based.
    
    Returns:
    returns the number of attributes
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
  - getAttributeNamespace
```
String getAttributeNamespace(int index)
```
    Returns the namespace of the attribute at the provided index
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    the namespace URI (can be null)
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no attribute at the specified index.
  - getAttributeLocalName
```
String getAttributeLocalName(int index)
```
    Returns the localName of the attribute at the provided index
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    the localName of the attribute
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no attribute at the specified index.
  - getAttributePrefix
```
String getAttributePrefix(int index)
```
    Returns the prefix of this attribute at the provided index
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    the prefix of the attribute
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no attribute at the specified index.
  - getAttributeType
```
String getAttributeType(int index)
```
    Returns the XML type of the attribute at the provided index (see XML 1.0 Specification, section 3.3.1)
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    the XML type of the attribute
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no attribute at the specified index.
  - getAttributeValue
```
String getAttributeValue(int index)
```
    Returns the value of the attribute at the index
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    the attribute value
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no attribute at the specified index.
  - isAttributeSpecified
```
boolean isAttributeSpecified(int index)
```
    Returns a boolean which indicates if this attribute was created by default
    
    Parameters:
    index - the position of the attribute
    
    Returns:
    true if this is a default attribute
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT or ATTRIBUTE
  - getNamespaceCount
```
int getNamespaceCount()
```
    Returns the count of namespaces declared on this START_ELEMENT or END_ELEMENT, this method is only valid on a START_ELEMENT, END_ELEMENT or NAMESPACE. On an END_ELEMENT the count is of the namespaces that are about to go out of scope. This is the equivalent of the information reported by SAX callback for an end element event.
    
    Returns:
    returns the number of namespace declarations on this specific element
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE
  - getNamespacePrefix
```
String getNamespacePrefix(int index)
```
    Returns the prefix for the namespace declared at the index. Returns null if this is the default namespace declaration
    
    Parameters:
    index - the position of the namespace declaration
    
    Returns:
    returns the namespace prefix
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE
    
    IndexOutOfBoundsException - if the index is invalid or if there is no namespace at the specified index
  - getNamespaceURI
```
String getNamespaceURI(int index)
```
    Returns the uri for the namespace declared at the index.
    
    Parameters:
    index - the position of the namespace declaration
    
    Returns:
    returns the namespace uri or null if none exists
    
    Throws:
    
    IllegalStateException - if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE
  - getEventType
```
int getEventType()
```
    Returns an integer code that indicates the type of the event the cursor is pointing to.
  - getText
```
String getText()
```
    Returns the current value of the parse event as a string, this returns the string value of a CHARACTERS event, returns the value of a COMMENT, the replacement value for an ENTITY_REFERENCE, the string value of a CDATA section, the string value for a SPACE event, or the String value of the internal subset of the DTD. If an ENTITY_REFERENCE has been resolved, any character data will be reported as CHARACTERS events.
    
    Returns:
    the current text or null
    
    Throws:
    
    IllegalStateException - if this state is not a valid text state.
  - getTextCharacters
```
char[] getTextCharacters()
```
    Returns an array which contains the characters from this event. This array should be treated as read-only and transient. I.e. the array will contain the text characters until the XMLStreamReader moves on to the next event. Attempts to hold onto the character array beyond that time or modify the contents of the array are breaches of the contract for this interface.
    
    Returns:
    the current text or an empty array
    
    Throws:
    
    IllegalStateException - if this state is not a valid text state.
  - getTextStart
```
int getTextStart()
```
    Returns the offset into the text character array where the first character (of this text event) is stored.
    
    Throws:
    
    IllegalStateException - if this state is not a valid text state.
  - getTextLength
```
int getTextLength()
```
    Returns the length of the sequence of characters for this Text event within the text character array.
    
    Throws:
    
    IllegalStateException - if this state is not a valid text state.
  - getEncoding
```
String getEncoding()
```
    Return input encoding if known or null if unknown.
    
    Returns:
    the encoding of this instance or null. Note: the source of the encoding is that that may have been provided by an application to the factory.
  - getLocation
```
Location getLocation()
```
    Return the current location of the processor. If the Location is unknown the processor should return an implementation of Location that returns -1 for the location and null for the publicId and systemId. The location information is only valid until next() is called.
  - getLocalName
```
String getLocalName()
```
    Returns the (local) name of the current event. For START_ELEMENT or END_ELEMENT returns the (local) name of the current element. For ENTITY_REFERENCE it returns entity name. The current event must be START_ELEMENT or END_ELEMENT, or ENTITY_REFERENCE
    
    Returns:
    the localName
    
    Throws:
    
    IllegalStateException - if this not a START_ELEMENT, END_ELEMENT or ENTITY_REFERENCE
  - getNamespaceURI
```
String getNamespaceURI()
```
    If the current event is a START_ELEMENT or END_ELEMENT this method returns the URI of the prefix or the default namespace. Returns null if the event does not have a prefix.
    
    Returns:
    the URI bound to this elements prefix, the default namespace, or null
  - getPrefix
```
String getPrefix()
```
    Returns the prefix of the current event or null if the event does not have a prefix
    
    Returns:
    the prefix or null
  - getVersion
```
String getVersion()
```
    Get the xml version declared on the xml declaration. Returns null if none was declared.
    
    Returns:
    the XML version or null
  - isStandalone
```
boolean isStandalone()
```
    Get the standalone declaration from the xml declaration
    
    Returns:
    true if this is standalone, or false otherwise
  - standaloneSet
```
boolean standaloneSet()
```
    Checks if standalone was set in the document
    
    Returns:
    true if standalone was set in the document, or false otherwise
  - getCharacterEncodingScheme
```
String getCharacterEncodingScheme()
```
    Returns the character encoding declared on the xml declaration Returns null if none was declared
    
    Returns:
    the encoding declared in the document or null
  - getPITarget
```
String getPITarget()
```
    Get the target of a processing instruction
    
    Returns:
    the target or null
  - getPIData
```
String getPIData()
```
    Get the data section of a processing instruction
    
    Returns:
    the data or null

Interface XMLStreamReader

Field Summary

Fields inherited from interface javax.xml.stream.XMLStreamConstants

Method Summary

Method Detail

getProperty

next

require

getElementText

nextTag

hasNext

close

getNamespaceURI

isWhiteSpace

getAttributeValue

getAttributeCount

getAttributeNamespace

getAttributeLocalName

getAttributePrefix

getAttributeType

getAttributeValue

isAttributeSpecified

getNamespaceCount

getNamespacePrefix

getNamespaceURI

getEventType

getText

getTextCharacters

getTextStart

getTextLength

getEncoding

getLocation

getLocalName

getNamespaceURI

getPrefix

getVersion

isStandalone

standaloneSet

getCharacterEncodingScheme

getPITarget

getPIData