J avolution v5.5 (J2SE 1.6+)

javolution.xml.stream
Interface XMLStreamReader

All Superinterfaces:
XMLStreamConstants
All Known Implementing Classes:
XMLStreamReaderImpl

public interface XMLStreamReader
extends XMLStreamConstants

This interface is similar to javax.xml.stream.XMLStreamReader; but it does not forces dynamic allocation when parsing (its methods returns CharArray instances instead of String).

Except for the speed (faster) and its real-time characteristics the usage/behavior is about the same as its StAX counterpart.

The CharArray instances returned by this reader supports fast primitive conversions as illustrated below:

     
     // Creates a new reader (potentially recycled).
     XMLInputFactory factory = XMLInputFactory.newInstance();
     XMLStreamReader reader = factory.createXMLStreamReader(inputStream);
     
     while (reader.getEventType() != XMLStreamConstants.END_DOCUMENT) {
         switch (reader.next()) {
             case XMLStreamConstants.START_ELEMENT:
             if (reader.getLocalName().equals("Time")) {
                  // Reads primitive types (int) attributes directly (no memory allocation).
                  time.hour = reader.getAttributeValue(null, "hour").toInt();
                  time.minute = reader.getAttributeValue(null, "minute").toInt();
                  time.second = reader.getAttributeValue(null, "second").toInt();
             }
             ...
             break;
         }         
     }
     
     reader.close(); // Recycles the reader.
     inputStream.close(); // Underlying stream has to be closed explicitly.
     

Version:
4.0, September 4, 2006
Author:
Jean-Marie Dautelle

Field Summary
 
Fields inherited from interface javolution.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
 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.
 CharArray getAttributeLocalName(int index)
          Returns the localName of the attribute at the provided index.
 CharArray getAttributeNamespace(int index)
          Returns the namespace of the attribute at the provided index
 CharArray getAttributePrefix(int index)
          Returns the prefix of this attribute at the provided index
 CharArray getAttributeType(int index)
          Returns the XML type of the attribute at the provided index.
 CharArray getAttributeValue(java.lang.CharSequence namespaceURI, java.lang.CharSequence localName)
          Returns the normalized attribute value of the attribute with the namespace and localName.
 CharArray getAttributeValue(int index)
          Returns the value of the attribute at the index.
 CharArray getCharacterEncodingScheme()
          Returns the character encoding declared on the xml declaration.
 CharArray getElementText()
          Reads the content of a text-only element, an exception is thrown if this is not a text-only element.
 java.lang.String getEncoding()
          Returns the 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.
 CharArray getLocalName()
          Returns the (local) name of the current event.
 Location getLocation()
          Return the current location of the processor.
 NamespaceContext getNamespaceContext()
          Returns a read only namespace context for the current position.
 int getNamespaceCount()
          Returns the count of namespaces declared on this START_ELEMENT or END_ELEMENT.
 CharArray getNamespacePrefix(int index)
          Returns the prefix for the namespace declared at the index.
 CharArray getNamespaceURI()
          If the current event is a START_ELEMENT or END_ELEMENT this method returns the URI of the current element (URI mapping to the prefix element/attribute has; or if no prefix null).
 CharArray getNamespaceURI(java.lang.CharSequence prefix)
          Returns the uri for the given prefix.
 CharArray getNamespaceURI(int index)
          Returns the URI for the namespace declared at the index.
 CharArray getPIData()
          Get the data section of a processing instruction.
 CharArray getPITarget()
          Returns the target of a processing instruction.
 CharArray getPrefix()
          Returns the prefix of the current event or null if the event does not have a prefix.
 java.lang.Object getProperty(java.lang.String name)
          Gets the value of a feature/property from the underlying implementation
 CharArray 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 getTextCharacters(int sourceStart, char[] target, int targetStart, int length)
          Gets the the text associated with a CHARACTERS, SPACE or CDATA 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.
 CharArray getVersion()
          Gets the xml version declared on the xml declaration.
 boolean hasName()
          Indicates if the current event has a name (is a START_ELEMENT or END_ELEMENT).
 boolean hasNext()
          Returns true if there are more parsing events and false if there are no more events.
 boolean hasText()
          Indicates if the current event has text.
 boolean isAttributeSpecified(int index)
          Indicates if this attribute was created by default.
 boolean isCharacters()
          Indicates if the cursor points to character data.
 boolean isEndElement()
          Indicates if the cursor points to an end tag.
 boolean isStandalone()
          Gets the standalone declaration from the xml declaration.
 boolean isStartElement()
          Indicates if the cursor points to a start tag.
 boolean isWhiteSpace()
          Indicates if the cursor points to character data that consists of all whitespace.
 int next()
          Gets next parsing event - contiguous character data is returned into a single chunk.
 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, java.lang.CharSequence namespaceURI, java.lang.CharSequence localName)
          Tests 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

java.lang.Object getProperty(java.lang.String name)
                             throws java.lang.IllegalArgumentException
Gets the value of a feature/property from the underlying implementation

Parameters:
name - the name of the property.
Returns:
the value of the property.
Throws:
java.lang.IllegalArgumentException

next

int next()
         throws XMLStreamException
Gets next parsing event - contiguous character data is returned into a single chunk. 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><!--description-->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>. This method will throw an IllegalStateException if it is called after hasNext() returns false.

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,
             java.lang.CharSequence namespaceURI,
             java.lang.CharSequence localName)
             throws XMLStreamException
Tests 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

CharArray 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 the 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 optimized 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 seperated 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 optimized but must do equivalent processing):
   int eventType = next();
   while((eventType == XMLStreamConstants.CHARACTERS && isWhiteSpace()) // skip whitespace
   || (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, 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

CharArray getNamespaceURI(java.lang.CharSequence prefix)
Returns 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.
Returns:
the uri bound to the given prefix or null if it is not bound

isStartElement

boolean isStartElement()
Indicates if the cursor points to a start tag.

Returns:
true if the cursor points to a start tag; false otherwise.

isEndElement

boolean isEndElement()
Indicates if the cursor points to an end tag.

Returns:
true if the cursor points to a end tag; false otherwise.

isCharacters

boolean isCharacters()
Indicates if the cursor points to character data.

Returns:
true if the cursor points to character data; false otherwise.

isWhiteSpace

boolean isWhiteSpace()
Indicates if the cursor points to character data that consists of all whitespace.

Returns:
true if the cursor points to whitespaces; false otherwise.

getAttributeValue

CharArray getAttributeValue(java.lang.CharSequence namespaceURI,
                            java.lang.CharSequence localName)
Returns the normalized attribute value of the attribute with the namespace and localName.

Parameters:
namespaceURI - the namespace of the attribute or null.
localName - the local name of the attribute.
Returns:
returns the value of the attribute or null.
Throws:
java.lang.IllegalStateException - if 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. Attribute indices are zero-based.

Returns:
returns the number of attributes.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

getAttributeNamespace

CharArray getAttributeNamespace(int index)
Returns the namespace of the attribute at the provided index

Parameters:
index - the position of the attribute.
Returns:
the namespace URI or null if no prefix.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

getAttributeLocalName

CharArray 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:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

getAttributePrefix

CharArray 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 or null if no prefix.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

getAttributeType

CharArray getAttributeType(int index)
Returns the XML type of the attribute at the provided index.

Parameters:
index - the position of the attribute
Returns:
the XML type of the attribute.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

getAttributeValue

CharArray getAttributeValue(int index)
Returns the value of the attribute at the index.

Parameters:
index - the position of the attribute.
Returns:
the attribute value.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or ATTRIBUTE.

isAttributeSpecified

boolean isAttributeSpecified(int index)
Indicates if this attribute was created by default.

Parameters:
index - the position of the attribute.
Returns:
true if this is a default attribute; false otherwise.
Throws:
java.lang.IllegalStateException - if 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:
java.lang.IllegalStateException - if not a START_ELEMENT or END_ELEMENT.

getNamespacePrefix

CharArray getNamespacePrefix(int index)
Returns the prefix for the namespace declared at the index.

Parameters:
index - the position of the namespace declaration.
Returns:
returns the namespace prefix or null if no prefix.
Throws:
java.lang.IllegalStateException - if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE.

getNamespaceURI

CharArray 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 no prefix.
Throws:
java.lang.IllegalStateException - if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE.

getNamespaceContext

NamespaceContext getNamespaceContext()
Returns a read only namespace context for the current position.

Returns:
return a namespace context

getEventType

int getEventType()
Returns an integer code that indicates the type of the event the cursor is pointing to.

Returns:
the event type.

getText

CharArray 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:
java.lang.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:
java.lang.IllegalStateException - if this state is not a valid text state.

getTextCharacters

int getTextCharacters(int sourceStart,
                      char[] target,
                      int targetStart,
                      int length)
                      throws XMLStreamException
Gets the the text associated with a CHARACTERS, SPACE or CDATA event. Text starting a "sourceStart" is copied into "target" starting at "targetStart". Up to "length" characters are copied. The number of characters actually copied is returned. The "sourceStart" argument must be greater or equal to 0 and less than or equal to the number of characters associated with the event. Usually, one requests text starting at a "sourceStart" of 0. If the number of characters actually copied is less than the "length", then there is no more text. Otherwise, subsequent calls need to be made until all text has been retrieved. For example: int length = 1024; char[] myBuffer = new char[ length ]; for ( int sourceStart = 0 ; ; sourceStart += length ) { int nCopied = stream.getTextCharacters( sourceStart, myBuffer, 0, length ); if (nCopied < length) break; } XMLStreamException may be thrown if there are any XML errors in the underlying source. The "targetStart" argument must be greater than or equal to 0 and less than the length of "target", Length must be greater than 0 and "targetStart + length" must be less than or equal to length of "target".

Parameters:
sourceStart - the index of te first character in the source array to copy
target - the destination array
targetStart - the start offset in the target array
length - the number of characters to copy
Returns:
the number of characters actually copied
Throws:
XMLStreamException - if the XML source is not well-formed.
java.lang.IndexOutOfBoundsException - if targetStart < 0 or > than the length of target
java.lang.IndexOutOfBoundsException - if length < 0 or targetStart + length > length of target
java.lang.UnsupportedOperationException - if this method is not supported.

getTextStart

int getTextStart()
Returns the offset into the text character array where the first character (of this text event) is stored.

Throws:
java.lang.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:
java.lang.IllegalStateException - if this state is not a valid text state.

getEncoding

java.lang.String getEncoding()
Returns the input encoding if known or null if unknown.

Returns:
the encoding of this instance or null.

hasText

boolean hasText()
Indicates if the current event has text. The following events have text: CHARACTERS, DTD ,ENTITY_REFERENCE, COMMENT, SPACE.

Returns:
true if the current event as text; false otherwise.

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.

Returns:
the current location.

getLocalName

CharArray 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:
java.lang.IllegalStateException - if this not a START_ELEMENT, END_ELEMENT or ENTITY_REFERENCE

hasName

boolean hasName()
Indicates if the current event has a name (is a START_ELEMENT or END_ELEMENT).

Returns:
true if the current event has a name; false otherwise.

getNamespaceURI

CharArray getNamespaceURI()
If the current event is a START_ELEMENT or END_ELEMENT this method returns the URI of the current element (URI mapping to the prefix element/attribute has; or if no prefix null).

Returns:
the URI bound to this elements prefix or null.
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT, END_ELEMENT or ATTRIBUTE.

getPrefix

CharArray getPrefix()
Returns the prefix of the current event or null if the event does not have a prefix.

Returns:
the prefix or null
Throws:
java.lang.IllegalStateException - if not a START_ELEMENT or END_ELEMENT.

getVersion

CharArray getVersion()
Gets the xml version declared on the xml declaration.

Returns:
the XML version or null

isStandalone

boolean isStandalone()
Gets the standalone declaration from the xml declaration.

Returns:
true if this is standalone; false otherwise.

standaloneSet

boolean standaloneSet()
Checks if standalone was set in the document.

Returns:
true if standalone was set; false otherwise.

getCharacterEncodingScheme

CharArray getCharacterEncodingScheme()
Returns the character encoding declared on the xml declaration.

Returns:
the encoding declared in the document or null

getPITarget

CharArray getPITarget()
Returns the target of a processing instruction.

Returns:
the target.
Throws:
java.lang.IllegalStateException - if the current event is not a XMLStreamConstants.PROCESSING_INSTRUCTION

getPIData

CharArray getPIData()
Get the data section of a processing instruction.

Returns:
the data (if processing instruction has any) or null if the processing instruction only has target.
Throws:
java.lang.IllegalStateException - if the current event is not a XMLStreamConstants.PROCESSING_INSTRUCTION

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