Package net.sf.saxon.event

## Class SignificantItemDetector

- java.lang.Object
- - net.sf.saxon.event.Outputter
  - - net.sf.saxon.event.ProxyOutputter
    - - net.sf.saxon.event.SignificantItemDetector

- All Implemented Interfaces:
    `javax.xml.transform.Result`, `Receiver`

      public class SignificantItemDetector
      extends ProxyOutputter

  This receiver is inserted into the output pipeline whenever on-empty or on-non-empty is used (XSLT 3.0). It passes all events to the underlying receiver unchanged, but invokes a callback action when the first item is written.

- - ### Field Summary

    - ### Fields inherited from class net.sf.saxon.event.Outputter

      `pipelineConfiguration, systemId`

    - ### Fields inherited from interface javax.xml.transform.Result

      `PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING`

  - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `SignificantItemDetector​(Outputter next, Action trigger)` |

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `append​(Item item, Location locationId, int copyNamespaces)` | Append an arbitrary item (node, atomic value, or function) to the output.
    `void` | `attribute​(NodeName attName, SimpleType typeCode, java.lang.CharSequence value, Location location, int properties)` | Notify an attribute.
    `void` | `characters​(java.lang.CharSequence chars, Location locationId, int properties)` | Notify character data.
    `void` | `comment​(java.lang.CharSequence chars, Location locationId, int properties)` | Notify a comment.
    `void` | `endDocument()` | Notify the end of a document node
    `void` | `endElement()` | End of element
    `boolean` | `isEmpty()` | Ask if the sequence that has been written so far is considered empty
    `static boolean` | `isSignificant​(Item item)` |
    `void` | `namespace​(java.lang.String prefix, java.lang.String namespaceUri, int properties)` | Notify a namespace binding.
    `void` | `processingInstruction​(java.lang.String target, java.lang.CharSequence data, Location locationId, int properties)` | Output a processing instruction
    `void` | `startContent()` | Notify the start of the content, that is, the completion of all attributes and namespaces.
    `void` | `startDocument​(int properties)` | Start of a document node.
    `void` | `startElement​(NodeName elemName, SchemaType type, AttributeMap attributes, NamespaceMap namespaces, Location location, int properties)` | Notify the start of an element, supplying all attributes and namespaces
    `void` | `startElement​(NodeName elemName, SchemaType type, Location location, int properties)` | Notify the start of an element

    - ### Methods inherited from class net.sf.saxon.event.ProxyOutputter

      `append, close, getNextOutputter, open, setLocation, setUnparsedEntity, usesTypeAnnotations`

    - ### Methods inherited from class net.sf.saxon.event.Outputter

      `getConfiguration, getPipelineConfiguration, getStringReceiver, getSystemId, namespaces, setPipelineConfiguration, setSystemId`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

    - ### Methods inherited from interface net.sf.saxon.event.Receiver

      `handlesAppend`

- - ### Constructor Detail

    - #### SignificantItemDetector

          public SignificantItemDetector​(Outputter next,
                                         Action trigger)

  - ### Method Detail

    - #### startDocument

          public void startDocument​(int properties)
                             throws XPathException

      Start of a document node.
      Specified by:
        `startDocument` in interface `Receiver`
      Overrides:
        `startDocument` in class `ProxyOutputter`
      Parameters:
        `properties` - bit-significant integer indicating properties of the document node. The definitions of the bits are in class `ReceiverOption`
      Throws:
        `XPathException` - if an error occurs

    - #### startElement

          public void startElement​(NodeName elemName,
                                   SchemaType type,
                                   Location location,
                                   int properties)
                            throws XPathException

      Description copied from class: `ProxyOutputter`
      Notify the start of an element
      Overrides:
        `startElement` in class `ProxyOutputter`
      Parameters:
        `elemName` - the name of the element.
        `type` - the type annotation of the element.
        `location` - an object providing information about the module, line, and column where the node originated
        `properties` - bit-significant properties of the element node. If there are no relevant properties, zero is supplied. The definitions of the bits are in class `ReceiverOption`
      Throws:
        `XPathException` - if an error occurs

    - #### startElement

          public void startElement​(NodeName elemName,
                                   SchemaType type,
                                   AttributeMap attributes,
                                   NamespaceMap namespaces,
                                   Location location,
                                   int properties)
                            throws XPathException

      Notify the start of an element, supplying all attributes and namespaces
      Specified by:
        `startElement` in interface `Receiver`
      Overrides:
        `startElement` in class `ProxyOutputter`
      Parameters:
        `elemName` - the name of the element.
        `type` - the type annotation of the element.
        `attributes` - the attributes of this element
        `namespaces` - the in-scope namespaces of this element: generally this is all the in-scope namespaces, without relying on inheriting namespaces from parent elements
        `location` - an object providing information about the module, line, and column where the node originated
        `properties` - bit-significant properties of the element node. If there are no relevant properties, zero is supplied. The definitions of the bits are in class `ReceiverOption`
      Throws:
        `XPathException` - if an error occurs

    - #### namespace

          public void namespace​(java.lang.String prefix,
                                java.lang.String namespaceUri,
                                int properties)
                         throws XPathException

      Notify a namespace binding.
      Overrides:
        `namespace` in class `ProxyOutputter`
      Parameters:
        `prefix` - The namespace prefix; zero-length string for the default namespace
        `namespaceUri` - The namespace URI. In some cases a zero-length string may be used to indicate a namespace undeclaration.
        `properties` - The REJECT_DUPLICATES property: if set, the namespace declaration will be rejected if it conflicts with a previous declaration of the same prefix. If the property is not set, the namespace declaration will be ignored if it conflicts with a previous declaration. This reflects the fact that when copying a tree, namespaces for child elements are emitted before the namespaces of their parent element. Unfortunately this conflicts with the XSLT rule for complex content construction, where the recovery action in the event of conflicts is to take the namespace that comes last. XSLT therefore doesn't recover from this error:
      Throws:
        `XPathException` - if an error occurs

    - #### attribute

          public void attribute​(NodeName attName,
                                SimpleType typeCode,
                                java.lang.CharSequence value,
                                Location location,
                                int properties)
                         throws XPathException

      Notify an attribute.
      Overrides:
        `attribute` in class `ProxyOutputter`
      Parameters:
        `attName` - The name of the attribute
        `typeCode` - The type annotation of the attribute
        `value` - the string value of the attribute
        `location` - provides information such as line number and system ID.
        `properties` - Bit significant value. The following bits are defined:
        DISABLE_ESCAPING
          Disable escaping for this attribute
        NO_SPECIAL_CHARACTERS
          Attribute value contains no special characters
      Throws:
        `XPathException` - if an error occurs

    - #### startContent

          public void startContent()
                            throws XPathException

      Notify the start of the content, that is, the completion of all attributes and namespaces.
      Overrides:
        `startContent` in class `ProxyOutputter`
      Throws:
        `XPathException` - if an error occurs

    - #### characters

          public void characters​(java.lang.CharSequence chars,
                                 Location locationId,
                                 int properties)
                          throws XPathException

      Description copied from class: `ProxyOutputter`
      Notify character data. Note that some receivers may require the character data to be sent in a single event, but in general this is not a requirement.
      Specified by:
        `characters` in interface `Receiver`
      Overrides:
        `characters` in class `ProxyOutputter`
      Parameters:
        `chars` - The characters
        `locationId` - provides information such as line number and system ID.
        `properties` - Bit significant value. The following bits are defined:
        DISABLE_ESCAPING
          Disable escaping for this text node
        USE_CDATA
          Output as a CDATA section
      Throws:
        `XPathException` - if an error occurs

    - #### processingInstruction

          public void processingInstruction​(java.lang.String target,
                                            java.lang.CharSequence data,
                                            Location locationId,
                                            int properties)
                                     throws XPathException

      Description copied from class: `ProxyOutputter`
      Output a processing instruction
      Specified by:
        `processingInstruction` in interface `Receiver`
      Overrides:
        `processingInstruction` in class `ProxyOutputter`
      Parameters:
        `target` - The PI name. This must be a legal name (it will not be checked).
        `data` - The data portion of the processing instruction
        `locationId` - provides information such as line number and system ID.
        `properties` - Additional information about the PI.
      Throws:
        `XPathException` - if an error occurs

    - #### comment

          public void comment​(java.lang.CharSequence chars,
                              Location locationId,
                              int properties)
                       throws XPathException

      Description copied from class: `ProxyOutputter`
      Notify a comment. Comments are only notified if they are outside the DTD.
      Specified by:
        `comment` in interface `Receiver`
      Overrides:
        `comment` in class `ProxyOutputter`
      Parameters:
        `chars` - The content of the comment
        `locationId` - provides information such as line number and system ID.
        `properties` - Additional information about the comment.
      Throws:
        `XPathException` - if an error occurs

    - #### isSignificant

          public static boolean isSignificant​(Item item)

    - #### append

          public void append​(Item item,
                             Location locationId,
                             int copyNamespaces)
                      throws XPathException

      Description copied from class: `ProxyOutputter`
      Append an arbitrary item (node, atomic value, or function) to the output. The default implementation throws `UnsupportedOperationException`.
      Specified by:
        `append` in interface `Receiver`
      Overrides:
        `append` in class `ProxyOutputter`
      Parameters:
        `item` - the item to be appended
        `locationId` - the location of the calling instruction, for diagnostics
        `copyNamespaces` - if the item is an element node, this indicates whether its namespaces need to be copied. Values are `ReceiverOption.ALL_NAMESPACES`; the default (0) means
      Throws:
        `XPathException` - if an error occurs

    - #### endDocument

          public void endDocument()
                           throws XPathException

      Notify the end of a document node
      Specified by:
        `endDocument` in interface `Receiver`
      Overrides:
        `endDocument` in class `ProxyOutputter`
      Throws:
        `XPathException` - if an error occurs

    - #### endElement

          public void endElement()
                          throws XPathException

      End of element
      Specified by:
        `endElement` in interface `Receiver`
      Overrides:
        `endElement` in class `ProxyOutputter`
      Throws:
        `XPathException` - if an error occurs

    - #### isEmpty

          public boolean isEmpty()

      Ask if the sequence that has been written so far is considered empty
      Returns:
        true if no significant items have been written (or started)