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 is
* provided through the property API on this interface.
* The following two properties allow access to this information:
* javax.xml.stream.notations and javax.xml.stream.entities.
* When the current event is a DTD the following call will return a
* list of Notations
* List l = (List) getProperty("javax.xml.stream.notations");
* The following call will return a list of entity declarations:
* List l = (List) getProperty("javax.xml.stream.entities");
* These properties can only be accessed during a DTD event and
* are defined to return null if the information is not available.
*
*
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(), isStartElement(), * isEndElement(), isCharacters(), isWhiteSpace(), * getNamespaceContext(), getEventType(),getLocation(), * hasText(), hasName() * | *
| START_ELEMENT | *next(), getName(), getLocalName(), hasName(), getPrefix(), * getAttributeXXX(), isAttributeSpecified(), * getNamespaceXXX(), * getElementText(), nextTag() * | *ATTRIBUTE | *next(), nextTag() * getAttributeXXX(), isAttributeSpecified(), * | * * *NAMESPACE | *next(), nextTag() * getNamespaceXXX() * | * *
| END_ELEMENT | *next(), getName(), getLocalName(), hasName(), 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() | *
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.
* @see javax.xml.stream.events.XMLEvent
* @return the integer code corresponding to the current parse event
* @throws NoSuchElementException if this is called when hasNext() returns false
* @throws XMLStreamException if there is an error processing the underlying XML source
*/
public int next() 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.
* @param type the event type
* @param namespaceURI the uri of the event, may be null
* @param localName the localName of the event, may be null
* @throws XMLStreamException if the required values are not matched.
*/
public void require(int type, String namespaceURI, String localName) 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 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
*/
public String getElementText() 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.
*
*
* 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;
*
*
* @return 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
* @throws NoSuchElementException if this is called when hasNext() returns false
*/
public int nextTag() 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
* @return true if there are more events, false otherwise
* @throws XMLStreamException if there is a fatal error detecting the next state
*/
public boolean hasNext() 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
*/
public void close() throws XMLStreamException;
/**
* 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/ * @param prefix The prefix to lookup, may not be null * @return the uri bound to the given prefix or null if it is not bound * @throws IllegalArgumentException if the prefix is null */ public String getNamespaceURI(String prefix); /** * Returns true if the cursor points to a start tag (otherwise false) * @return true if the cursor points to a start tag, false otherwise */ public boolean isStartElement(); /** * Returns true if the cursor points to an end tag (otherwise false) * @return true if the cursor points to an end tag, false otherwise */ public boolean isEndElement(); /** * Returns true if the cursor points to a character data event * @return true if the cursor points to character data, false otherwise */ public boolean isCharacters(); /** * Returns true if the cursor points to a character data event * that consists of all whitespace * @return true if the cursor points to all whitespace, false otherwise */ public boolean isWhiteSpace(); /** * Returns the normalized attribute value of the * attribute with the namespace and localName * If the namespaceURI is null the namespace * is not checked for equality * @param namespaceURI the namespace of the attribute * @param localName the local name of the attribute, cannot be null * @return returns the value of the attribute , returns null if not found * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributeValue(String namespaceURI, String localName); /** * 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. * @return returns the number of attributes * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public int getAttributeCount(); /** Returns the qname of the attribute at the provided index * * @param index the position of the attribute * @return the QName of the attribute * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public QName getAttributeName(int index); /** * Returns the namespace of the attribute at the provided * index * @param index the position of the attribute * @return the namespace URI (can be null) * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributeNamespace(int index); /** * Returns the localName of the attribute at the provided * index * @param index the position of the attribute * @return the localName of the attribute * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributeLocalName(int index); /** * Returns the prefix of this attribute at the * provided index * @param index the position of the attribute * @return the prefix of the attribute * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributePrefix(int index); /** * Returns the XML type of the attribute at the provided * index * @param index the position of the attribute * @return the XML type of the attribute * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributeType(int index); /** * Returns the value of the attribute at the * index * @param index the position of the attribute * @return the attribute value * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public String getAttributeValue(int index); /** * Returns a boolean which indicates if this * attribute was created by default * @param index the position of the attribute * @return true if this is a default attribute * @throws IllegalStateException if this is not a START_ELEMENT or ATTRIBUTE */ public boolean isAttributeSpecified(int index); /** * 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. * @return returns the number of namespace declarations on this specific element * @throws IllegalStateException if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE */ public int getNamespaceCount(); /** * Returns the prefix for the namespace declared at the * index. Returns null if this is the default namespace * declaration * * @param index the position of the namespace declaration * @return returns the namespace prefix * @throws IllegalStateException if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE */ public String getNamespacePrefix(int index); /** * Returns the uri for the namespace declared at the * index. * * @param index the position of the namespace declaration * @return returns the namespace uri * @throws IllegalStateException if this is not a START_ELEMENT, END_ELEMENT or NAMESPACE */ public String getNamespaceURI(int index); /** * Returns a read only namespace context for the current * position. The context is transient and only valid until * a call to next() changes the state of the reader. * @return return a namespace context */ public NamespaceContext getNamespaceContext(); /** * Returns a reader that points to the current start element * and all of its contents. Throws an XMLStreamException if the * cursor does not point to a START_ELEMENT.
* The sub stream is read from it MUST be read before the parent stream is
* moved on, if not any call on the sub stream will cause an XMLStreamException to be
* thrown. The parent stream will always return the same result from next()
* whatever is done to the sub stream.
* @return an XMLStreamReader which points to the next element
*/
// public XMLStreamReader subReader() throws XMLStreamException;
/**
* Allows the implementation to reset and reuse any underlying tables
*/
// public void recycle() throws XMLStreamException;
/**
* Returns an integer code that indicates the type
* of the event the cursor is pointing to.
*/
public int getEventType();
/**
* 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.
* @return the current text or null
* @throws java.lang.IllegalStateException if this state is not
* a valid text state.
*/
public String getText();
/**
* 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.
* @return the current text or an empty array
* @throws java.lang.IllegalStateException if this state is not
* a valid text state.
*/
public char[] getTextCharacters();
/**
* 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".
*
* @param sourceStart the index of the first character in the source array to copy
* @param target the destination array
* @param targetStart the start offset in the target array
* @param length the number of characters to copy
* @return the number of characters actually copied
* @throws XMLStreamException if the underlying XML source is not well-formed
* @throws IndexOutOfBoundsException if targetStart < 0 or > than the length of target
* @throws IndexOutOfBoundsException if length < 0 or targetStart + length > length of target
* @throws UnsupportedOperationException if this method is not supported
* @throws NullPointerException is if target is null
*/
public int getTextCharacters(int sourceStart, char[] target, int targetStart, int length)
throws XMLStreamException;
/**
* Gets the text associated with a CHARACTERS, SPACE or CDATA event. Allows the underlying
* implementation to return the text as a stream of characters. The reference to the
* Reader returned by this method is only valid until next() is called.
*
* All characters must have been checked for well-formedness.
*
*
This method is optional and will throw UnsupportedOperationException if it is not supported. * @throws UnsupportedOperationException if this method is not supported * @throws IllegalStateException if this is not a valid text state */ //public Reader getTextStream(); /** * 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. */ public int getTextStart(); /** * 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. */ public int getTextLength(); /** * Return input encoding if known or null if unknown. * @return the encoding of this instance or null */ public String getEncoding(); /** * Return true if the current event has text, false otherwise * The following events have text: * CHARACTERS,DTD ,ENTITY_REFERENCE, COMMENT, SPACE */ public boolean hasText(); /** * 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. */ public Location getLocation(); /** * Returns a QName for the current START_ELEMENT or END_ELEMENT event * @return the QName for the current START_ELEMENT or END_ELEMENT event * @throws IllegalStateException if this is not a START_ELEMENT or * END_ELEMENT */ public QName getName(); /** * 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 * @return the localName * @throws IllegalStateException if this not a START_ELEMENT, * END_ELEMENT or ENTITY_REFERENCE */ public String getLocalName(); /** * returns true if the current event has a name (is a START_ELEMENT or END_ELEMENT) * returns false otherwise */ public boolean hasName(); /** * 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. * @return the URI bound to this elements prefix, the default namespace, or null */ public String getNamespaceURI(); /** * Returns the prefix of the current event or null if the event does not have a prefix * @return the prefix or null */ public String getPrefix(); /** * Get the xml version declared on the xml declaration * Returns null if none was declared * @return the XML version or null */ public String getVersion(); /** * Get the standalone declaration from the xml declaration * @return true if this is standalone, or false otherwise */ public boolean isStandalone(); /** * Checks if standalone was set in the document * @return true if standalone was set in the document, or false otherwise */ public boolean standaloneSet(); /** * Returns the character encoding declared on the xml declaration * Returns null if none was declared * @return the encoding declared in the document or null */ public String getCharacterEncodingScheme(); /** * Get the target of a processing instruction * @return the target or null */ public String getPITarget(); /** * Get the data section of a processing instruction * @return the data or null */ public String getPIData(); }