IIOMetadataFormat (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Standard Ed. 5.0

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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 implentation will construct only a single instance and cache it for future invocations of getInstance.

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

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 '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

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 th enamed element.

String getAttributeDefaultValue(String elementName, String attrName)
          Returns the default value of the named attribute, if it is not explictly 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 Strings 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 Strings 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 Strings 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 Objects containing the default value for the Object reference within the named element.

Object[] getObjectEnumerations(String elementName)
          Returns an array of Objects 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 Summary
`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 '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
`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 th enamed element.
`String`	`getAttributeDefaultValue(String elementName, String attrName)` Returns the default value of the named attribute, if it is not explictly 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 getAttributeValueTypeor 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 getAttributeValueTypeor 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 Strings; for objects, they are Objects 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 'true' or 'false'.

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 primay.

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 desciption 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 Strings 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 Strings, 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 Strings 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 Strings.
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 th enamed 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 attribut 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 explictly 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 Strings 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 Strings.
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 desciption 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 ints, 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 Objects 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 Objects 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 emuerated 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 Objects.
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.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

IIOMetadataFormat (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

javax.imageio.metadata Interface IIOMetadataFormat

CHILD_POLICY_EMPTY

CHILD_POLICY_ALL

CHILD_POLICY_SOME

CHILD_POLICY_CHOICE

CHILD_POLICY_SEQUENCE

CHILD_POLICY_REPEAT

CHILD_POLICY_MAX

VALUE_NONE

VALUE_ARBITRARY

VALUE_RANGE

VALUE_RANGE_MIN_INCLUSIVE_MASK

VALUE_RANGE_MAX_INCLUSIVE_MASK

VALUE_RANGE_MIN_INCLUSIVE

VALUE_RANGE_MAX_INCLUSIVE

VALUE_RANGE_MIN_MAX_INCLUSIVE

VALUE_ENUMERATION

VALUE_LIST

DATATYPE_STRING

DATATYPE_BOOLEAN

DATATYPE_INTEGER

DATATYPE_FLOAT

DATATYPE_DOUBLE

getRootName

canNodeAppear

getElementMinChildren

getElementMaxChildren

getElementDescription

getChildPolicy

getChildNames

getAttributeNames

getAttributeValueType

getAttributeDataType

isAttributeRequired

getAttributeDefaultValue

getAttributeEnumerations

getAttributeMinValue

getAttributeMaxValue

getAttributeListMinLength

getAttributeListMaxLength

getAttributeDescription

getObjectValueType

getObjectClass

getObjectDefaultValue

getObjectEnumerations

getObjectMinValue

getObjectMaxValue

getObjectArrayMinLength

getObjectArrayMaxLength

javax.imageio.metadata
Interface IIOMetadataFormat