# Interface DocumentType

All Superinterfaces:
  `Node`

public interface DocumentType extends Node
Each `Document` has a `doctype` attribute whose value is either `null` or a `DocumentType` object. The `DocumentType` interface in the DOM Core provides an interface to the list of entities that are defined for the document, and little else because the effect of namespaces and the various XML schema efforts on DTD representation are not clearly understood as of this writing.

DOM Level 3 doesn't support editing `DocumentType` nodes. `DocumentType` nodes are read-only.

See also the Document Object Model (DOM) Level 3 Core Specification.

Since:
  1.4, DOM Level 2

- ## Field Summary

  ### Fields declared in interface Node

  `ATTRIBUTE_NODE, CDATA_SECTION_NODE, COMMENT_NODE, DOCUMENT_FRAGMENT_NODE, DOCUMENT_NODE, DOCUMENT_POSITION_CONTAINED_BY, DOCUMENT_POSITION_CONTAINS, DOCUMENT_POSITION_DISCONNECTED, DOCUMENT_POSITION_FOLLOWING, DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC, DOCUMENT_POSITION_PRECEDING, DOCUMENT_TYPE_NODE, ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, NOTATION_NODE, PROCESSING_INSTRUCTION_NODE, TEXT_NODE`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `NamedNodeMap`
  `getEntities()`
  A `NamedNodeMap` containing the general entities, both external and internal, declared in the DTD.
  `String`
  `getInternalSubset()`
  The internal subset as a string, or `null` if there is none.
  `String`
  `getName()`
  The name of DTD; i.e., the name immediately following the `DOCTYPE` keyword.
  `NamedNodeMap`
  `getNotations()`
  A `NamedNodeMap` containing the notations declared in the DTD.
  `String`
  `getPublicId()`
  The public identifier of the external subset.
  `String`
  `getSystemId()`
  The system identifier of the external subset.

  ### Methods declared in interface Node

  `appendChild, cloneNode, compareDocumentPosition, getAttributes, getBaseURI, getChildNodes, getFeature, getFirstChild, getLastChild, getLocalName, getNamespaceURI, getNextSibling, getNodeName, getNodeType, getNodeValue, getOwnerDocument, getParentNode, getPrefix, getPreviousSibling, getTextContent, getUserData, hasAttributes, hasChildNodes, insertBefore, isDefaultNamespace, isEqualNode, isSameNode, isSupported, lookupNamespaceURI, lookupPrefix, normalize, removeChild, replaceChild, setNodeValue, setPrefix, setTextContent, setUserData`

- ## Method Details

  - ### getName

    String getName()
    The name of DTD; i.e., the name immediately following the `DOCTYPE` keyword.

  - ### getEntities

    NamedNodeMap getEntities()
    A `NamedNodeMap` containing the general entities, both external and internal, declared in the DTD. Parameter entities are not contained. Duplicates are discarded. For example in:

        <!DOCTYPE
        ex SYSTEM "ex.dtd" [ <!ENTITY foo "foo"> <!ENTITY bar
        "bar"> <!ENTITY bar "bar2"> <!ENTITY % baz "baz">
        ]> <ex/>

    the interface provides access to `foo` and the first declaration of `bar` but not the second declaration of `bar` or `baz`. Every node in this map also implements the `Entity` interface.
    The DOM Level 2 does not support editing entities, therefore `entities` cannot be altered in any way.

  - ### getNotations

    NamedNodeMap getNotations()
    A `NamedNodeMap` containing the notations declared in the DTD. Duplicates are discarded. Every node in this map also implements the `Notation` interface.
    The DOM Level 2 does not support editing notations, therefore `notations` cannot be altered in any way.

  - ### getPublicId

    String getPublicId()
    The public identifier of the external subset.
    Since:
      1.4, DOM Level 2

  - ### getSystemId

    String getSystemId()
    The system identifier of the external subset. This may be an absolute URI or not.
    Since:
      1.4, DOM Level 2

  - ### getInternalSubset

    String getInternalSubset()
    The internal subset as a string, or `null` if there is none. This is does not contain the delimiting square brackets.

    Note: The actual content returned depends on how much information is available to the implementation. This may vary depending on various parameters, including the XML processor used to build the document.

    Since:
      1.4, DOM Level 2