# Interface XMLStreamWriter

public interface XMLStreamWriter
The XMLStreamWriter interface specifies how to write XML. The XMLStreamWriter does not perform well formedness checking on its input. However the writeCharacters method is required to escape &, < and > For attribute values the writeAttribute method will escape the above characters plus " to ensure that all character content and attribute values are well formed. Each NAMESPACE and ATTRIBUTE must be individually written.

XML Namespaces, `javax.xml.stream.isRepairingNamespaces` and write method behaviour
Method | `isRepairingNamespaces` == true | `isRepairingNamespaces` == false
--- | --- | ---
namespaceURI bound | namespaceURI unbound | namespaceURI bound | namespaceURI unbound
`writeAttribute(namespaceURI, localName, value)` | prefix:localName="value" [1] | xmlns:{generated}="namespaceURI" {generated}:localName="value" | prefix:localName="value" [1] | `XMLStreamException`
`writeAttribute(prefix, namespaceURI, localName, value)` | bound to same prefix: prefix:localName="value" [1] bound to different prefix: xmlns:{generated}="namespaceURI" {generated}:localName="value" | xmlns:prefix="namespaceURI" prefix:localName="value" [3] | bound to same prefix: prefix:localName="value" [1][2] bound to different prefix: `XMLStreamException`[2] | xmlns:prefix="namespaceURI" prefix:localName="value" [2][5]
`writeStartElement(namespaceURI, localName)` `writeEmptyElement(namespaceURI, localName)` | `<prefix:localName>` [1] | `<{generated}:localName xmlns:{generated}="namespaceURI">` | `prefix:localName>` [1] | `XMLStreamException`
`writeStartElement(prefix, localName, namespaceURI)` `writeEmptyElement(prefix, localName, namespaceURI)` | bound to same prefix: `<prefix:localName>` [1] bound to different prefix: `<{generated}:localName xmlns:{generated}="namespaceURI">` | `<prefix:localName xmlns:prefix="namespaceURI">` [4] | bound to same prefix: `<prefix:localName>` [1] bound to different prefix: `XMLStreamException` | `<prefix:localName>`

Notes:

- [1] if namespaceURI == default Namespace URI, then no prefix is written
- [2] if prefix == "" || null && namespaceURI == "", then no prefix or Namespace declaration is generated or written
- [3] if prefix == "" || null, then a prefix is randomly generated
- [4] if prefix == "" || null, then it is treated as the default Namespace and no prefix is generated or written, an xmlns declaration is generated and written if the namespaceURI is unbound
- [5] if prefix == "" || null, then it is treated as an invalid attempt to define the default Namespace and an XMLStreamException is thrown

Since:
  1.6
See Also:
  - `XMLOutputFactory`
  - `XMLStreamReader`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `close()`
  Close this writer and free any resources associated with the writer.
  `void`
  `flush()`
  Write any cached data to the underlying output mechanism.
  `NamespaceContext`
  `getNamespaceContext()`
  Returns the current namespace context.
  `String`
  `getPrefix(String uri)`
  Gets the prefix the uri is bound to.
  `Object`
  `getProperty(String name)`
  Get the value of a feature/property from the underlying implementation
  `void`
  `setDefaultNamespace(String uri)`
  Binds a URI to the default namespace This URI is bound in the scope of the current START_ELEMENT / END_ELEMENT pair.
  `void`
  `setNamespaceContext(NamespaceContext context)`
  Sets the current namespace context for prefix and uri bindings.
  `void`
  `setPrefix(String prefix, String uri)`
  Sets the prefix the uri is bound to.
  `void`
  `writeAttribute(String localName, String value)`
  Writes an attribute to the output stream without a prefix.
  `void`
  `writeAttribute(String namespaceURI, String localName, String value)`
  Writes an attribute to the output stream
  `void`
  `writeAttribute(String prefix, String namespaceURI, String localName, String value)`
  Writes an attribute to the output stream
  `void`
  `writeCData(String data)`
  Writes a CData section
  `void`
  `writeCharacters(char[] text, int start, int len)`
  Write text to the output
  `void`
  `writeCharacters(String text)`
  Write text to the output
  `void`
  `writeComment(String data)`
  Writes an xml comment with the data enclosed
  `void`
  `writeDefaultNamespace(String namespaceURI)`
  Writes the default namespace to the stream
  `void`
  `writeDTD(String dtd)`
  Write a DTD section.
  `void`
  `writeEmptyElement(String localName)`
  Writes an empty element tag to the output
  `void`
  `writeEmptyElement(String namespaceURI, String localName)`
  Writes an empty element tag to the output
  `void`
  `writeEmptyElement(String prefix, String localName, String namespaceURI)`
  Writes an empty element tag to the output
  `void`
  `writeEndDocument()`
  Closes any start tags and writes corresponding end tags.
  `void`
  `writeEndElement()`
  Writes an end tag to the output relying on the internal state of the writer to determine the prefix and local name of the event.
  `void`
  `writeEntityRef(String name)`
  Writes an entity reference
  `void`
  `writeNamespace(String prefix, String namespaceURI)`
  Writes a namespace to the output stream If the prefix argument to this method is the empty string, "xmlns", or null this method will delegate to writeDefaultNamespace
  `void`
  `writeProcessingInstruction(String target)`
  Writes a processing instruction
  `void`
  `writeProcessingInstruction(String target, String data)`
  Writes a processing instruction
  `void`
  `writeStartDocument()`
  Write the XML Declaration.
  `void`
  `writeStartDocument(String version)`
  Write the XML Declaration.
  `void`
  `writeStartDocument(String encoding, String version)`
  Write the XML Declaration.
  `void`
  `writeStartElement(String localName)`
  Writes a start tag to the output.
  `void`
  `writeStartElement(String namespaceURI, String localName)`
  Writes a start tag to the output
  `void`
  `writeStartElement(String prefix, String localName, String namespaceURI)`
  Writes a start tag to the output

- ## Method Details

  - ### writeStartElement

    void writeStartElement(String localName) throws XMLStreamException
    Writes a start tag to the output. All writeStartElement methods open a new scope in the internal namespace context. Writing the corresponding EndElement causes the scope to be closed.
    Parameters:
      `localName` - local name of the tag, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeStartElement

    void writeStartElement(String namespaceURI, String localName) throws XMLStreamException
    Writes a start tag to the output
    Parameters:
      `namespaceURI` - the namespaceURI of the prefix to use, may not be null
      `localName` - local name of the tag, may not be null
    Throws:
      `XMLStreamException` - if the namespace URI has not been bound to a prefix and javax.xml.stream.isRepairingNamespaces has not been set to true

  - ### writeStartElement

    void writeStartElement(String prefix, String localName, String namespaceURI) throws XMLStreamException
    Writes a start tag to the output
    Parameters:
      `prefix` - the prefix of the tag, may not be null
      `localName` - local name of the tag, may not be null
      `namespaceURI` - the uri to bind the prefix to, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeEmptyElement

    void writeEmptyElement(String namespaceURI, String localName) throws XMLStreamException
    Writes an empty element tag to the output
    Parameters:
      `namespaceURI` - the uri to bind the tag to, may not be null
      `localName` - local name of the tag, may not be null
    Throws:
      `XMLStreamException` - if the namespace URI has not been bound to a prefix and javax.xml.stream.isRepairingNamespaces has not been set to true

  - ### writeEmptyElement

    void writeEmptyElement(String prefix, String localName, String namespaceURI) throws XMLStreamException
    Writes an empty element tag to the output
    Parameters:
      `prefix` - the prefix of the tag, may not be null
      `localName` - local name of the tag, may not be null
      `namespaceURI` - the uri to bind the tag to, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeEmptyElement

    void writeEmptyElement(String localName) throws XMLStreamException
    Writes an empty element tag to the output
    Parameters:
      `localName` - local name of the tag, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeEndElement

    void writeEndElement() throws XMLStreamException
    Writes an end tag to the output relying on the internal state of the writer to determine the prefix and local name of the event.
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeEndDocument

    void writeEndDocument() throws XMLStreamException
    Closes any start tags and writes corresponding end tags.
    Throws:
      `XMLStreamException` - if an error occurs

  - ### close

    void close() throws XMLStreamException
    Close this writer and free any resources associated with the writer. This must not close the underlying output stream.
    Throws:
      `XMLStreamException` - if an error occurs

  - ### flush

    void flush() throws XMLStreamException
    Write any cached data to the underlying output mechanism.
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeAttribute

    void writeAttribute(String localName, String value) throws XMLStreamException
    Writes an attribute to the output stream without a prefix.
    Parameters:
      `localName` - the local name of the attribute
      `value` - the value of the attribute
    Throws:
      `IllegalStateException` - if the current state does not allow Attribute writing
      `XMLStreamException` - if an error occurs

  - ### writeAttribute

    void writeAttribute(String prefix, String namespaceURI, String localName, String value) throws XMLStreamException
    Writes an attribute to the output stream
    Parameters:
      `prefix` - the prefix for this attribute
      `namespaceURI` - the uri of the prefix for this attribute
      `localName` - the local name of the attribute
      `value` - the value of the attribute
    Throws:
      `IllegalStateException` - if the current state does not allow Attribute writing
      `XMLStreamException` - if the namespace URI has not been bound to a prefix and javax.xml.stream.isRepairingNamespaces has not been set to true

  - ### writeAttribute

    void writeAttribute(String namespaceURI, String localName, String value) throws XMLStreamException
    Writes an attribute to the output stream
    Parameters:
      `namespaceURI` - the uri of the prefix for this attribute
      `localName` - the local name of the attribute
      `value` - the value of the attribute
    Throws:
      `IllegalStateException` - if the current state does not allow Attribute writing
      `XMLStreamException` - if the namespace URI has not been bound to a prefix and javax.xml.stream.isRepairingNamespaces has not been set to true

  - ### writeNamespace

    void writeNamespace(String prefix, String namespaceURI) throws XMLStreamException
    Writes a namespace to the output stream If the prefix argument to this method is the empty string, "xmlns", or null this method will delegate to writeDefaultNamespace
    Parameters:
      `prefix` - the prefix to bind this namespace to
      `namespaceURI` - the uri to bind the prefix to
    Throws:
      `IllegalStateException` - if the current state does not allow Namespace writing
      `XMLStreamException` - if an error occurs

  - ### writeDefaultNamespace

    void writeDefaultNamespace(String namespaceURI) throws XMLStreamException
    Writes the default namespace to the stream
    Parameters:
      `namespaceURI` - the uri to bind the default namespace to
    Throws:
      `IllegalStateException` - if the current state does not allow Namespace writing
      `XMLStreamException` - if an error occurs

  - ### writeComment

    void writeComment(String data) throws XMLStreamException
    Writes an xml comment with the data enclosed
    Parameters:
      `data` - the data contained in the comment, may be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeProcessingInstruction

    void writeProcessingInstruction(String target) throws XMLStreamException
    Writes a processing instruction
    Parameters:
      `target` - the target of the processing instruction, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeProcessingInstruction

    void writeProcessingInstruction(String target, String data) throws XMLStreamException
    Writes a processing instruction
    Parameters:
      `target` - the target of the processing instruction, may not be null
      `data` - the data contained in the processing instruction, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeCData

    void writeCData(String data) throws XMLStreamException
    Writes a CData section
    Parameters:
      `data` - the data contained in the CData Section, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeDTD

    void writeDTD(String dtd) throws XMLStreamException
    Write a DTD section. This string represents the entire doctypedecl production from the XML 1.0 specification.
    Parameters:
      `dtd` - the DTD to be written
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeEntityRef

    void writeEntityRef(String name) throws XMLStreamException
    Writes an entity reference
    Parameters:
      `name` - the name of the entity
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeStartDocument

    void writeStartDocument() throws XMLStreamException
    Write the XML Declaration. Defaults the XML version to 1.0, and the encoding to utf-8
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeStartDocument

    void writeStartDocument(String version) throws XMLStreamException
    Write the XML Declaration. Defaults the XML version to 1.0
    Parameters:
      `version` - version of the xml document
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeStartDocument

    void writeStartDocument(String encoding, String version) throws XMLStreamException
    Write the XML Declaration. Note that the encoding parameter does not set the actual encoding of the underlying output. That must be set when the instance of the XMLStreamWriter is created using the XMLOutputFactory
    Parameters:
      `encoding` - encoding of the xml declaration
      `version` - version of the xml document
    Throws:
      `XMLStreamException` - If given encoding does not match encoding of the underlying stream

  - ### writeCharacters

    void writeCharacters(String text) throws XMLStreamException
    Write text to the output
    Parameters:
      `text` - the value to write
    Throws:
      `XMLStreamException` - if an error occurs

  - ### writeCharacters

    void writeCharacters(char[] text, int start, int len) throws XMLStreamException
    Write text to the output
    Parameters:
      `text` - the value to write
      `start` - the starting position in the array
      `len` - the number of characters to write
    Throws:
      `XMLStreamException` - if an error occurs

  - ### getPrefix

    String getPrefix(String uri) throws XMLStreamException
    Gets the prefix the uri is bound to.
    Parameters:
      `uri` - the uri the prefix is bound to
    Returns:
      the prefix or null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### setPrefix

    void setPrefix(String prefix, String uri) throws XMLStreamException
    Sets the prefix the uri is bound to. This prefix is bound in the scope of the current START_ELEMENT / END_ELEMENT pair. If this method is called before a START_ELEMENT has been written the prefix is bound in the root scope.
    Parameters:
      `prefix` - the prefix to bind to the uri, may not be null
      `uri` - the uri to bind to the prefix, may be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### setDefaultNamespace

    void setDefaultNamespace(String uri) throws XMLStreamException
    Binds a URI to the default namespace This URI is bound in the scope of the current START_ELEMENT / END_ELEMENT pair. If this method is called before a START_ELEMENT has been written the uri is bound in the root scope.
    Parameters:
      `uri` - the uri to bind to the default namespace, may be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### setNamespaceContext

    void setNamespaceContext(NamespaceContext context) throws XMLStreamException
    Sets the current namespace context for prefix and uri bindings. This context becomes the root namespace context for writing and will replace the current root namespace context. Subsequent calls to setPrefix and setDefaultNamespace will bind namespaces using the context passed to the method as the root context for resolving namespaces. This method may only be called once at the start of the document. It does not cause the namespaces to be declared. If a namespace URI to prefix mapping is found in the namespace context it is treated as declared and the prefix may be used by the StreamWriter.
    Parameters:
      `context` - the namespace context to use for this writer, may not be null
    Throws:
      `XMLStreamException` - if an error occurs

  - ### getNamespaceContext

    NamespaceContext getNamespaceContext()
    Returns the current namespace context.
    Returns:
      the current NamespaceContext

  - ### 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 the property is not supported
      `NullPointerException` - if the name is null