IIOMetadataFormat (Java SE 9 & JDK 9 )
Keywords: javax.imageio.metadata.IIOMetadataFormat interface

Module java.desktop
Package javax.imageio.metadata

## Interface IIOMetadataFormat

- All Known Implementing Classes:
    `IIOMetadataFormatImpl`

      public interface IIOMetadataFormat

  An object describing the structure of metadata documents returned from `IIOMetadata.getAsTree` and passed to `IIOMetadata.setFromTree` and `mergeTree`. Document structures are described by a set of constraints on the type and number of child elements that may belong to a given parent element type, the names, types, and values of attributes that may belong to an element, and the type and values of `Object` reference that may be stored at a node.

  N.B: classes that implement this interface should contain a method declared as `public static getInstance()` which returns an instance of the class. Commonly, an implementation will construct only a single instance and cache it for future invocations of `getInstance`.

  In the event that the plugin is provided as part of a named module, that module must export the package containing the implementation class to the

      java.desktop

  module via a qualified export. An unqualified export is not recommended unless also needed for some other reason. Failing to export the package will result in access failure at runtime.

  The structures that may be described by this class are a subset of those expressible using XML document type definitions (DTDs), with the addition of some basic information on the datatypes of attributes and the ability to store an `Object` reference within a node. In the future, XML Schemas could be used to represent these structures, and many others.

  The differences between `IIOMetadataFormat`-described structures and DTDs are as follows:

  - Elements may not contain text or mix text with embedded tags.
  - The children of an element must conform to one of a few simple patterns, described in the documentation for the `CHILD_*` constants;
  - The in-memory representation of an elements may contain a reference to an `Object`. There is no provision for representing such objects textually.

- - ### Field Summary

    Fields
    Modifier and Type | Field | Description
    --- | --- | ---
    `static int` | `CHILD_POLICY_ALL` | A constant returned by `getChildPolicy` to indicate that an element must have a single instance of each of its legal child elements, in order.
    `static int` | `CHILD_POLICY_CHOICE` | A constant returned by `getChildPolicy` to indicate that an element must have zero or one children, selected from among its legal child elements.
    `static int` | `CHILD_POLICY_EMPTY` | A constant returned by `getChildPolicy` to indicate that an element may not have any children.
    `static int` | `CHILD_POLICY_MAX` | The largest valid `CHILD_POLICY_*` constant, to be used for range checks.
    `static int` | `CHILD_POLICY_REPEAT` | A constant returned by `getChildPolicy` to indicate that an element must have zero or more instances of its unique legal child element.
    `static int` | `CHILD_POLICY_SEQUENCE` | A constant returned by `getChildPolicy` to indicate that an element must have a sequence of instances of any of its legal child elements.
    `static int` | `CHILD_POLICY_SOME` | A constant returned by `getChildPolicy` to indicate that an element must have zero or one instance of each of its legal child elements, in order.
    `static int` | `DATATYPE_BOOLEAN` | A constant returned by `getAttributeDataType` indicating that the value of an attribute is one of the boolean values 'true' or 'false'.
    `static int` | `DATATYPE_DOUBLE` | A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of a double-precision decimal floating-point number.
    `static int` | `DATATYPE_FLOAT` | A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of a decimal floating-point number.
    `static int` | `DATATYPE_INTEGER` | A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of an integer.
    `static int` | `DATATYPE_STRING` | A constant returned by `getAttributeDataType` indicating that the value of an attribute is a general Unicode string.
    `static int` | `VALUE_ARBITRARY` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a single, arbitrary value.
    `static int` | `VALUE_ENUMERATION` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set one of a number of enumerated values.
    `static int` | `VALUE_LIST` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a list or array of values.
    `static int` | `VALUE_NONE` | A constant returned by `getObjectValueType` to indicate the absence of a user object.
    `static int` | `VALUE_RANGE` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a range of values.
    `static int` | `VALUE_RANGE_MAX_INCLUSIVE` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a range of values.
    `static int` | `VALUE_RANGE_MAX_INCLUSIVE_MASK` | A value that may be or'ed with `VALUE_RANGE` to obtain `VALUE_RANGE_MAX_INCLUSIVE`, and with `VALUE_RANGE_MIN_INCLUSIVE` to obtain `VALUE_RANGE_MIN_MAX_INCLUSIVE`.
    `static int` | `VALUE_RANGE_MIN_INCLUSIVE` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a range of values.
    `static int` | `VALUE_RANGE_MIN_INCLUSIVE_MASK` | A value that may be or'ed with `VALUE_RANGE` to obtain `VALUE_RANGE_MIN_INCLUSIVE`, and with `VALUE_RANGE_MAX_INCLUSIVE` to obtain `VALUE_RANGE_MIN_MAX_INCLUSIVE`.
    `static int` | `VALUE_RANGE_MIN_MAX_INCLUSIVE` | A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a range of values.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `boolean` | `canNodeAppear​(String elementName, ImageTypeSpecifier imageType)` | Returns `true` if the element (and the subtree below it) is allowed to appear in a metadata document for an image of the given type, defined by an `ImageTypeSpecifier`.
    `int` | `getAttributeDataType​(String elementName, String attrName)` | Returns one of the constants starting with `DATATYPE_`, indicating the format and interpretation of the value of the given attribute within the named element.
    `String` | `getAttributeDefaultValue​(String elementName, String attrName)` | Returns the default value of the named attribute, if it is not explicitly present within the named element, as a `String`, or `null` if no default value is available.
    `String` | `getAttributeDescription​(String elementName, String attrName, Locale locale)` | Returns a `String` containing a description of the named attribute, or `null`.
    `String[]` | `getAttributeEnumerations​(String elementName, String attrName)` | Returns an array of `String`s containing the legal enumerated values for the given attribute within the named element.
    `int` | `getAttributeListMaxLength​(String elementName, String attrName)` | Returns the maximum number of list items that may be used to define this attribute.
    `int` | `getAttributeListMinLength​(String elementName, String attrName)` | Returns the minimum number of list items that may be used to define this attribute.
    `String` | `getAttributeMaxValue​(String elementName, String attrName)` | Returns the maximum legal value for the attribute.
    `String` | `getAttributeMinValue​(String elementName, String attrName)` | Returns the minimum legal value for the attribute.
    `String[]` | `getAttributeNames​(String elementName)` | Returns an array of `String`s listing the names of the attributes that may be associated with the named element.
    `int` | `getAttributeValueType​(String elementName, String attrName)` | Returns one of the constants starting with `VALUE_`, indicating whether the values of the given attribute within the named element are arbitrary, constrained to lie within a specified range, constrained to be one of a set of enumerated values, or are a whitespace-separated list of arbitrary values.
    `String[]` | `getChildNames​(String elementName)` | Returns an array of `String`s indicating the names of the element which are allowed to be children of the named element, in the order in which they should appear.
    `int` | `getChildPolicy​(String elementName)` | Returns one of the constants starting with `CHILD_POLICY_`, indicating the legal pattern of children for the named element.
    `String` | `getElementDescription​(String elementName, Locale locale)` | Returns a `String` containing a description of the named element, or `null`.
    `int` | `getElementMaxChildren​(String elementName)` | Returns the maximum number of children of the named element with child policy `CHILD_POLICY_REPEAT`.
    `int` | `getElementMinChildren​(String elementName)` | Returns the minimum number of children of the named element with child policy `CHILD_POLICY_REPEAT`.
    `int` | `getObjectArrayMaxLength​(String elementName)` | Returns the maximum number of array elements that may be used to define the `Object` reference within the named element.
    `int` | `getObjectArrayMinLength​(String elementName)` | Returns the minimum number of array elements that may be used to define the `Object` reference within the named element.
    `Class<?>` | `getObjectClass​(String elementName)` | Returns the `Class` type of the `Object` reference stored within the element.
    `Object` | `getObjectDefaultValue​(String elementName)` | Returns an `Object`s containing the default value for the `Object` reference within the named element.
    `Object[]` | `getObjectEnumerations​(String elementName)` | Returns an array of `Object`s containing the legal enumerated values for the `Object` reference within the named element.
    `Comparable<?>` | `getObjectMaxValue​(String elementName)` | Returns the maximum legal value for the `Object` reference within the named element.
    `Comparable<?>` | `getObjectMinValue​(String elementName)` | Returns the minimum legal value for the `Object` reference within the named element.
    `int` | `getObjectValueType​(String elementName)` | Returns one of the enumerated values starting with `VALUE_`, indicating the type of values (enumeration, range, or array) that are allowed for the `Object` reference.
    `String` | `getRootName​()` | Returns the name of the root element of the format.
    `boolean` | `isAttributeRequired​(String elementName, String attrName)` | Returns `true` if the named attribute must be present within the named element.

- - ### Field Detail

    - #### CHILD_POLICY_EMPTY

          static final int CHILD_POLICY_EMPTY

      A constant returned by `getChildPolicy` to indicate that an element may not have any children. In other words, it is required to be a leaf node.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_ALL

          static final int CHILD_POLICY_ALL

      A constant returned by `getChildPolicy` to indicate that an element must have a single instance of each of its legal child elements, in order. In DTD terms, the contents of the element are defined by a sequence `a,b,c,d,...`.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_SOME

          static final int CHILD_POLICY_SOME

      A constant returned by `getChildPolicy` to indicate that an element must have zero or one instance of each of its legal child elements, in order. In DTD terms, the contents of the element are defined by a sequence `a?,b?,c?,d?,...`.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_CHOICE

          static final int CHILD_POLICY_CHOICE

      A constant returned by `getChildPolicy` to indicate that an element must have zero or one children, selected from among its legal child elements. In DTD terms, the contents of the element are defined by a selection `a|b|c|d|...`.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_SEQUENCE

          static final int CHILD_POLICY_SEQUENCE

      A constant returned by `getChildPolicy` to indicate that an element must have a sequence of instances of any of its legal child elements. In DTD terms, the contents of the element are defined by a sequence `(a|b|c|d|...)*`.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_REPEAT

          static final int CHILD_POLICY_REPEAT

      A constant returned by `getChildPolicy` to indicate that an element must have zero or more instances of its unique legal child element. In DTD terms, the contents of the element are defined by a starred expression `a*`.
      See Also:
        Constant Field Values

    - #### CHILD_POLICY_MAX

          static final int CHILD_POLICY_MAX

      The largest valid `CHILD_POLICY_*` constant, to be used for range checks.
      See Also:
        Constant Field Values

    - #### VALUE_NONE

          static final int VALUE_NONE

      A constant returned by `getObjectValueType` to indicate the absence of a user object.
      See Also:
        Constant Field Values

    - #### VALUE_ARBITRARY

          static final int VALUE_ARBITRARY

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a single, arbitrary value.
      See Also:
        Constant Field Values

    - #### VALUE_RANGE

          static final int VALUE_RANGE

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a range of values. Both the minimum and maximum values of the range are exclusive. It is recommended that ranges of integers be inclusive on both ends, and that exclusive ranges be used only for floating-point data.
      See Also:
        `VALUE_RANGE_MIN_MAX_INCLUSIVE`, Constant Field Values

    - #### VALUE_RANGE_MIN_INCLUSIVE_MASK

          static final int VALUE_RANGE_MIN_INCLUSIVE_MASK

      A value that may be or'ed with `VALUE_RANGE` to obtain `VALUE_RANGE_MIN_INCLUSIVE`, and with `VALUE_RANGE_MAX_INCLUSIVE` to obtain `VALUE_RANGE_MIN_MAX_INCLUSIVE`.

      Similarly, the value may be and'ed with the value of `getAttributeValueType` or `getObjectValueType` to determine if the minimum value of the range is inclusive.

      See Also:
        Constant Field Values

    - #### VALUE_RANGE_MAX_INCLUSIVE_MASK

          static final int VALUE_RANGE_MAX_INCLUSIVE_MASK

      A value that may be or'ed with `VALUE_RANGE` to obtain `VALUE_RANGE_MAX_INCLUSIVE`, and with `VALUE_RANGE_MIN_INCLUSIVE` to obtain `VALUE_RANGE_MIN_MAX_INCLUSIVE`.

      Similarly, the value may be and'ed with the value of `getAttributeValueType` or `getObjectValueType` to determine if the maximum value of the range is inclusive.

      See Also:
        Constant Field Values

    - #### VALUE_RANGE_MIN_INCLUSIVE

          static final int VALUE_RANGE_MIN_INCLUSIVE

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a range of values. The minimum (but not the maximum) value of the range is inclusive.
      See Also:
        Constant Field Values

    - #### VALUE_RANGE_MAX_INCLUSIVE

          static final int VALUE_RANGE_MAX_INCLUSIVE

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a range of values. The maximum (but not the minimum) value of the range is inclusive.
      See Also:
        Constant Field Values

    - #### VALUE_RANGE_MIN_MAX_INCLUSIVE

          static final int VALUE_RANGE_MIN_MAX_INCLUSIVE

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set a range of values. Both the minimum and maximum values of the range are inclusive. It is recommended that ranges of integers be inclusive on both ends, and that exclusive ranges be used only for floating-point data.
      See Also:
        Constant Field Values

    - #### VALUE_ENUMERATION

          static final int VALUE_ENUMERATION

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set one of a number of enumerated values. In the case of attributes, these values are `String`s; for objects, they are `Object`s implementing a given class or interface.

      Attribute values of type `DATATYPE_BOOLEAN` should be marked as enumerations.

      See Also:
        Constant Field Values

    - #### VALUE_LIST

          static final int VALUE_LIST

      A constant returned by `getAttributeValueType` and `getObjectValueType` to indicate that the attribute or user object may be set to a list or array of values. In the case of attributes, the list will consist of whitespace-separated values within a `String`; for objects, an array will be used.
      See Also:
        Constant Field Values

    - #### DATATYPE_STRING

          static final int DATATYPE_STRING

      A constant returned by `getAttributeDataType` indicating that the value of an attribute is a general Unicode string.
      See Also:
        Constant Field Values

    - #### DATATYPE_BOOLEAN

          static final int DATATYPE_BOOLEAN

      A constant returned by `getAttributeDataType` indicating that the value of an attribute is one of the boolean values 'true' or 'false'. Attribute values of type DATATYPE_BOOLEAN should be marked as enumerations, and the permitted values should be the string literal values "TRUE" or "FALSE", although a plugin may also recognise lower or mixed case equivalents.
      See Also:
        Constant Field Values

    - #### DATATYPE_INTEGER

          static final int DATATYPE_INTEGER

      A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of an integer.
      See Also:
        Constant Field Values

    - #### DATATYPE_FLOAT

          static final int DATATYPE_FLOAT

      A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of a decimal floating-point number.
      See Also:
        Constant Field Values

    - #### DATATYPE_DOUBLE

          static final int DATATYPE_DOUBLE

      A constant returned by `getAttributeDataType` indicating that the value of an attribute is a string representation of a double-precision decimal floating-point number.
      See Also:
        Constant Field Values

  - ### Method Detail

    - #### getRootName

          String getRootName​()

      Returns the name of the root element of the format.
      Returns:
        a `String`.

    - #### canNodeAppear

          boolean canNodeAppear​(String elementName,
                                ImageTypeSpecifier imageType)

      Returns `true` if the element (and the subtree below it) is allowed to appear in a metadata document for an image of the given type, defined by an `ImageTypeSpecifier`. For example, a metadata document format might contain an element that describes the primary colors of the image, which would not be allowed when writing a grayscale image.
      Parameters:
        `elementName` - the name of the element being queried.
        `imageType` - an `ImageTypeSpecifier` indicating the type of the image that will be associated with the metadata.
      Returns:
        `true` if the node is meaningful for images of the given type.

    - #### getElementMinChildren

          int getElementMinChildren​(String elementName)

      Returns the minimum number of children of the named element with child policy `CHILD_POLICY_REPEAT`. For example, an element representing color primary information might be required to have at least 3 children, one for each primary.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an `int`.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element does not have a child policy of `CHILD_POLICY_REPEAT`.

    - #### getElementMaxChildren

          int getElementMaxChildren​(String elementName)

      Returns the maximum number of children of the named element with child policy `CHILD_POLICY_REPEAT`. For example, an element representing an entry in an 8-bit color palette might be allowed to repeat up to 256 times. A value of `Integer.MAX_VALUE` may be used to specify that there is no upper bound.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an `int`.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element does not have a child policy of `CHILD_POLICY_REPEAT`.

    - #### getElementDescription

          String getElementDescription​(String elementName,
                                       Locale locale)

      Returns a `String` containing a description of the named element, or `null`. The description will be localized for the supplied `Locale` if possible.

      If `locale` is `null`, the current default `Locale` returned by `Locale.getLocale` will be used.

      Parameters:
        `elementName` - the name of the element.
        `locale` - the `Locale` for which localization will be attempted.
      Returns:
        the element description.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null`, or is not a legal element name for this format.

    - #### getChildPolicy

          int getChildPolicy​(String elementName)

      Returns one of the constants starting with `CHILD_POLICY_`, indicating the legal pattern of children for the named element.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        one of the `CHILD_POLICY_*` constants.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.

    - #### getChildNames

          String[] getChildNames​(String elementName)

      Returns an array of `String`s indicating the names of the element which are allowed to be children of the named element, in the order in which they should appear. If the element cannot have children, `null` is returned.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an array of `String`s, or null.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.

    - #### getAttributeNames

          String[] getAttributeNames​(String elementName)

      Returns an array of `String`s listing the names of the attributes that may be associated with the named element.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an array of `String`s.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.

    - #### getAttributeValueType

          int getAttributeValueType​(String elementName,
                                    String attrName)

      Returns one of the constants starting with `VALUE_`, indicating whether the values of the given attribute within the named element are arbitrary, constrained to lie within a specified range, constrained to be one of a set of enumerated values, or are a whitespace-separated list of arbitrary values.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        one of the `VALUE_*` constants.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.

    - #### getAttributeDataType

          int getAttributeDataType​(String elementName,
                                   String attrName)

      Returns one of the constants starting with `DATATYPE_`, indicating the format and interpretation of the value of the given attribute within the named element. If `getAttributeValueType` returns `VALUE_LIST`, then the legal value is a whitespace-spearated list of values of the returned datatype.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        one of the `DATATYPE_*` constants.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.

    - #### isAttributeRequired

          boolean isAttributeRequired​(String elementName,
                                      String attrName)

      Returns `true` if the named attribute must be present within the named element.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        `true` if the attribute must be present.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.

    - #### getAttributeDefaultValue

          String getAttributeDefaultValue​(String elementName,
                                          String attrName)

      Returns the default value of the named attribute, if it is not explicitly present within the named element, as a `String`, or `null` if no default value is available.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        a `String` containing the default value, or `null`.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.

    - #### getAttributeEnumerations

          String[] getAttributeEnumerations​(String elementName,
                                            String attrName)

      Returns an array of `String`s containing the legal enumerated values for the given attribute within the named element. This method should only be called if `getAttributeValueType` returns `VALUE_ENUMERATION`.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        an array of `String`s.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.
        `IllegalArgumentException` - if the given attribute is not defined as an enumeration.

    - #### getAttributeMinValue

          String getAttributeMinValue​(String elementName,
                                      String attrName)

      Returns the minimum legal value for the attribute. Whether this value is inclusive or exclusive may be determined by the value of `getAttributeValueType`. The value is returned as a `String`; its interpretation is dependent on the value of `getAttributeDataType`. This method should only be called if `getAttributeValueType` returns `VALUE_RANGE_*`.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        a `String` containing the smallest legal value for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.
        `IllegalArgumentException` - if the given attribute is not defined as a range.

    - #### getAttributeMaxValue

          String getAttributeMaxValue​(String elementName,
                                      String attrName)

      Returns the maximum legal value for the attribute. Whether this value is inclusive or exclusive may be determined by the value of `getAttributeValueType`. The value is returned as a `String`; its interpretation is dependent on the value of `getAttributeDataType`. This method should only be called if `getAttributeValueType` returns `VALUE_RANGE_*`.
      Parameters:
        `elementName` - the name of the element being queried, as a `String`.
        `attrName` - the name of the attribute being queried.
      Returns:
        a `String` containing the largest legal value for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.
        `IllegalArgumentException` - if the given attribute is not defined as a range.

    - #### getAttributeListMinLength

          int getAttributeListMinLength​(String elementName,
                                        String attrName)

      Returns the minimum number of list items that may be used to define this attribute. The attribute itself is defined as a `String` containing multiple whitespace-separated items. This method should only be called if `getAttributeValueType` returns `VALUE_LIST`.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        the smallest legal number of list items for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.
        `IllegalArgumentException` - if the given attribute is not defined as a list.

    - #### getAttributeListMaxLength

          int getAttributeListMaxLength​(String elementName,
                                        String attrName)

      Returns the maximum number of list items that may be used to define this attribute. A value of `Integer.MAX_VALUE` may be used to specify that there is no upper bound. The attribute itself is defined as a `String` containing multiple whitespace-separated items. This method should only be called if `getAttributeValueType` returns `VALUE_LIST`.
      Parameters:
        `elementName` - the name of the element being queried.
        `attrName` - the name of the attribute being queried.
      Returns:
        the largest legal number of list items for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.
        `IllegalArgumentException` - if the given attribute is not defined as a list.

    - #### getAttributeDescription

          String getAttributeDescription​(String elementName,
                                         String attrName,
                                         Locale locale)

      Returns a `String` containing a description of the named attribute, or `null`. The description will be localized for the supplied `Locale` if possible.

      If `locale` is `null`, the current default `Locale` returned by `Locale.getLocale` will be used.

      Parameters:
        `elementName` - the name of the element.
        `attrName` - the name of the attribute.
        `locale` - the `Locale` for which localization will be attempted.
      Returns:
        the attribute description.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null`, or is not a legal element name for this format.
        `IllegalArgumentException` - if `attrName` is `null` or is not a legal attribute name for this element.

    - #### getObjectValueType

          int getObjectValueType​(String elementName)

      Returns one of the enumerated values starting with `VALUE_`, indicating the type of values (enumeration, range, or array) that are allowed for the `Object` reference. If no object value can be stored within the given element, the result of this method will be `VALUE_NONE`.

      `Object` references whose legal values are defined as a range must implement the `Comparable` interface.

      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        one of the `VALUE_*` constants.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
      See Also:
        `Comparable`

    - #### getObjectClass

          Class<?> getObjectClass​(String elementName)

      Returns the `Class` type of the `Object` reference stored within the element. If this element may not contain an `Object` reference, an `IllegalArgumentException` will be thrown. If the class type is an array, this field indicates the underlying class type (e.g, for an array of `int`s, this method would return `int.class`).

      `Object` references whose legal values are defined as a range must implement the `Comparable` interface.

      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        a `Class` object.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).

    - #### getObjectDefaultValue

          Object getObjectDefaultValue​(String elementName)

      Returns an `Object`s containing the default value for the `Object` reference within the named element.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an `Object`.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).

    - #### getObjectEnumerations

          Object[] getObjectEnumerations​(String elementName)

      Returns an array of `Object`s containing the legal enumerated values for the `Object` reference within the named element. This method should only be called if `getObjectValueType` returns `VALUE_ENUMERATION`.

      The `Object` associated with a node that accepts enumerated values must be equal to one of the values returned by this method, as defined by the `==` operator (as opposed to the `Object.equals` method).

      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        an array of `Object`s.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).
        `IllegalArgumentException` - if the `Object` is not defined as an enumeration.

    - #### getObjectMinValue

          Comparable<?> getObjectMinValue​(String elementName)

      Returns the minimum legal value for the `Object` reference within the named element. Whether this value is inclusive or exclusive may be determined by the value of `getObjectValueType`. This method should only be called if `getObjectValueType` returns one of the constants starting with `VALUE_RANGE`.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        the smallest legal value for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).
        `IllegalArgumentException` - if the `Object` is not defined as a range.

    - #### getObjectMaxValue

          Comparable<?> getObjectMaxValue​(String elementName)

      Returns the maximum legal value for the `Object` reference within the named element. Whether this value is inclusive or exclusive may be determined by the value of `getObjectValueType`. This method should only be called if `getObjectValueType` returns one of the constants starting with `VALUE_RANGE`.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        the smallest legal value for the attribute.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).
        `IllegalArgumentException` - if the `Object` is not defined as a range.

    - #### getObjectArrayMinLength

          int getObjectArrayMinLength​(String elementName)

      Returns the minimum number of array elements that may be used to define the `Object` reference within the named element. This method should only be called if `getObjectValueType` returns `VALUE_LIST`.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        the smallest valid array length for the `Object` reference.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).
        `IllegalArgumentException` - if the `Object` is not an array.

    - #### getObjectArrayMaxLength

          int getObjectArrayMaxLength​(String elementName)

      Returns the maximum number of array elements that may be used to define the `Object` reference within the named element. A value of `Integer.MAX_VALUE` may be used to specify that there is no upper bound. This method should only be called if `getObjectValueType` returns `VALUE_LIST`.
      Parameters:
        `elementName` - the name of the element being queried.
      Returns:
        the largest valid array length for the `Object` reference.
      Throws:
        `IllegalArgumentException` - if `elementName` is `null` or is not a legal element name for this format.
        `IllegalArgumentException` - if the named element cannot contain an object value (i.e., if `getObjectValueType(elementName) == VALUE_NONE`).
        `IllegalArgumentException` - if the `Object` is not an array.