org.apache.cayenne.configuration.xml

## Class SAXNestedTagHandler

- java.lang.Object
- - org.xml.sax.helpers.DefaultHandler
  - - org.apache.cayenne.configuration.xml.SAXNestedTagHandler

- All Implemented Interfaces:
    ContentHandler, DTDHandler, EntityResolver, ErrorHandler
  Direct Known Subclasses:
    NamespaceAwareNestedTagHandler

      public class SAXNestedTagHandler
      extends DefaultHandler

  A superclass of nested tag handlers for parsing of XML documents with SAX. This class is not namespace aware, i.e. tags like <info:property/> and <property/> will be treated as equal. Use `NamespaceAwareNestedTagHandler` if you need to process namespaces.
  Since:
    3.1, 4.1 redesigned and moved from `org.apache.cayenne.configuration` package
  See Also:
    `NamespaceAwareNestedTagHandler`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected LoaderContext` | `loaderContext`
    `protected Locator` | `locator`
    `protected ContentHandler` | `parentHandler`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SAXNestedTagHandler(LoaderContext loaderContext)`
    `SAXNestedTagHandler(SAXNestedTagHandler parentHandler)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected void` | `beforeScopeEnd()` Callback method that is called before this handler pushed out of parsers stack.
    `protected ContentHandler` | `createChildTagHandler(String namespaceURI, String localName, String qName, Attributes attributes)` This method should be used to create nested handlers to process children elements.
    `void` | `endElement(String namespaceURI, String localName, String qName)`
    `ContentHandler` | `getParentHandler()`
    `protected boolean` | `processElement(String namespaceURI, String localName, Attributes attributes)` Main method to process XML content.
    `void` | `setDocumentLocator(Locator locator)`
    `void` | `startElement(String namespaceURI, String localName, String qName, Attributes attributes)` This method directly called by SAX parser, do not override it directly, use `processElement(String, String, Attributes)` method instead to process content.
    `protected void` | `stop()`
    `protected String` | `unexpectedTagMessage(String tagFound, String... tagsExpected)`

    - ### Methods inherited from class org.xml.sax.helpers.DefaultHandler

      `characters, endDocument, endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, resolveEntity, skippedEntity, startDocument, startPrefixMapping, unparsedEntityDecl, warning`

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

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

- - ### Field Detail

    - #### loaderContext

          protected LoaderContext loaderContext

    - #### parentHandler

          protected ContentHandler parentHandler

    - #### locator

          protected Locator locator

  - ### Constructor Detail

    - #### SAXNestedTagHandler

          public SAXNestedTagHandler(LoaderContext loaderContext)

    - #### SAXNestedTagHandler

          public SAXNestedTagHandler(SAXNestedTagHandler parentHandler)

  - ### Method Detail

    - #### unexpectedTagMessage

          protected String unexpectedTagMessage(String tagFound,
                                                String... tagsExpected)

    - #### processElement

          protected boolean processElement(String namespaceURI,
                                           String localName,
                                           Attributes attributes)
                                    throws SAXException

      Main method to process XML content. Should be override in subclasses, by default do nothing. Return value should be true if tag was fully processed and shouldn't be passed down to child handler.
      Parameters:
        `namespaceURI` - namespace for tag
        `localName` - tag local name (i.e. w/o namespace prefix)
        `attributes` - tag attributes
      Returns:
        true if tag was processed
      Throws:
        `SAXException` - can be thrown to abort parsing
      See Also:
        `createChildTagHandler(String, String, String, Attributes)`

    - #### beforeScopeEnd

          protected void beforeScopeEnd()

      Callback method that is called before this handler pushed out of parsers stack. Can be used to flush some aggregate state.

    - #### createChildTagHandler

          protected ContentHandler createChildTagHandler(String namespaceURI,
                                                         String localName,
                                                         String qName,
                                                         Attributes attributes)

      This method should be used to create nested handlers to process children elements. This method should never return `null`.
      Parameters:
        `namespaceURI` - namespace for tag
        `localName` - tag local name (i.e. w/o namespace prefix)
        `qName` - tag full name (i.e. with namespace prefix)
        `attributes` - tag attributes
      Returns:
        new handler to process child tag

    - #### stop

          protected void stop()

    - #### startElement

          public void startElement(String namespaceURI,
                                   String localName,
                                   String qName,
                                   Attributes attributes)
                            throws SAXException

      This method directly called by SAX parser, do not override it directly, use `processElement(String, String, Attributes)` method instead to process content.
      Specified by:
        `startElement` in interface `ContentHandler`
      Overrides:
        `startElement` in class `DefaultHandler`
      Throws:
        `SAXException`
      See Also:
        `createChildTagHandler(String, String, String, Attributes)`

    - #### endElement

          public void endElement(String namespaceURI,
                                 String localName,
                                 String qName)
                          throws SAXException

      Specified by:
        `endElement` in interface `ContentHandler`
      Overrides:
        `endElement` in class `DefaultHandler`
      Throws:
        `SAXException`

    - #### setDocumentLocator

          public void setDocumentLocator(Locator locator)

      Specified by:
        `setDocumentLocator` in interface `ContentHandler`
      Overrides:
        `setDocumentLocator` in class `DefaultHandler`

    - #### getParentHandler

          public ContentHandler getParentHandler()

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