java.awt.datatransfer

Class DataFlavor

  • All Implemented Interfaces:
    Externalizable, Serializable, Cloneable
    Direct Known Subclasses:
    ActivationDataFlavor 

    public class DataFlavor
extends Object
implements Externalizable, Cloneable
    A DataFlavor provides meta information about data. DataFlavor is typically used to access data on the clipboard, or during a drag and drop operation.

    An instance of DataFlavor encapsulates a content type as defined in RFC 2045 and RFC 2046. A content type is typically referred to as a MIME type.

    A content type consists of a media type (referred to as the primary type), a subtype, and optional parameters. See RFC 2045 for details on the syntax of a MIME type.

    The JRE data transfer implementation interprets the parameter "class" of a MIME type as a representation class. The representation class reflects the class of the object being transferred. In other words, the representation class is the type of object returned by Transferable.getTransferData(java.awt.datatransfer.DataFlavor). For example, the MIME type of imageFlavor is "image/x-java-image;class=java.awt.Image", the primary type is image, the subtype is x-java-image, and the representation class is java.awt.Image. When getTransferData is invoked with a DataFlavor of imageFlavor, an instance of java.awt.Image is returned. It's important to note that DataFlavor does no error checking against the representation class. It is up to consumers of DataFlavor, such as Transferable, to honor the representation class.
    Note, if you do not specify a representation class when creating a DataFlavor, the default representation class is used. See appropriate documentation for DataFlavor's constructors.

    Also, DataFlavor instances with the "text" primary MIME type may have a "charset" parameter. Refer to RFC 2046 and selectBestTextFlavor(java.awt.datatransfer.DataFlavor[]) for details on "text" MIME types and the "charset" parameter.

    Equality of DataFlavors is determined by the primary type, subtype, and representation class. Refer to equals(DataFlavor) for details. When determining equality, any optional parameters are ignored. For example, the following produces two DataFlavors that are considered identical: 

       DataFlavor flavor1 = new DataFlavor(Object.class, "X-test/test; class=<java.lang.Object>; foo=bar");
   DataFlavor flavor2 = new DataFlavor(Object.class, "X-test/test; class=<java.lang.Object>; x=y");
   // The following returns true.
   flavor1.equals(flavor2);
    As mentioned, flavor1 and flavor2 are considered identical. As such, asking a Transferable for either DataFlavor returns the same results.

    For more information on the using data transfer with Swing see the How to Use Drag and Drop and Data Transfer, section in Java Tutorial.

    See Also:
    Serialized Form

    • Field Detail

      • stringFlavor

        public static final DataFlavor stringFlavor
        The DataFlavor representing a Java Unicode String class, where: 
             representationClass = java.lang.String
     mimeType           = "application/x-java-serialized-object"

      • imageFlavor

        public static final DataFlavor imageFlavor
        The DataFlavor representing a Java Image class, where: 
             representationClass = java.awt.Image
     mimeType            = "image/x-java-image"

      • plainTextFlavor

        @Deprecated
public static final DataFlavor plainTextFlavor
        Deprecated.  as of 1.3. Use DataFlavor.getReaderForText(Transferable) instead of Transferable.getTransferData(DataFlavor.plainTextFlavor).
        The DataFlavor representing plain text with Unicode encoding, where: 
             representationClass = InputStream
     mimeType            = "text/plain; charset=unicode"
        This DataFlavor has been deprecated because (1) Its representation is an InputStream, an 8-bit based representation, while Unicode is a 16-bit character set; and (2) The charset "unicode" is not well-defined. "unicode" implies a particular platform's implementation of Unicode, not a cross-platform implementation.

      • javaSerializedObjectMimeType

        public static final String javaSerializedObjectMimeType
        A MIME Content-Type of application/x-java-serialized-object represents a graph of Java object(s) that have been made persistent. The representation class associated with this DataFlavor identifies the Java type of an object returned as a reference from an invocation java.awt.datatransfer.getTransferData.
        See Also:
        Constant Field Values

      • javaFileListFlavor

        public static final DataFlavor javaFileListFlavor
        To transfer a list of files to/from Java (and the underlying platform) a DataFlavor of this type/subtype and representation class of java.util.List is used. Each element of the list is required/guaranteed to be of type java.io.File.

      • javaJVMLocalObjectMimeType

        public static final String javaJVMLocalObjectMimeType
        To transfer a reference to an arbitrary Java object reference that has no associated MIME Content-type, across a Transferable interface WITHIN THE SAME JVM, a DataFlavor with this type/subtype is used, with a representationClass equal to the type of the class/interface being passed across the Transferable.

        The object reference returned from Transferable.getTransferData for a DataFlavor with this MIME Content-Type is required to be an instance of the representation Class of the DataFlavor.

        See Also:
        Constant Field Values

      • javaRemoteObjectMimeType

        public static final String javaRemoteObjectMimeType
        In order to pass a live link to a Remote object via a Drag and Drop ACTION_LINK operation a Mime Content Type of application/x-java-remote-object should be used, where the representation class of the DataFlavor represents the type of the Remote interface to be transferred.
        See Also:
        Constant Field Values

      • selectionHtmlFlavor

        public static DataFlavor selectionHtmlFlavor
        Represents a piece of an HTML markup. The markup consists of the part selected on the source side. Therefore some tags in the markup may be unpaired. If the flavor is used to represent the data in a Transferable instance, no additional changes will be made. This DataFlavor instance represents the same HTML markup as DataFlavor instances which content MIME type does not contain document parameter and representation class is the String class. 
             representationClass = String
     mimeType           = "text/html"

      • fragmentHtmlFlavor

        public static DataFlavor fragmentHtmlFlavor
        Represents a piece of an HTML markup. If possible, the markup received from a native system is supplemented with pair tags to be a well-formed HTML markup. If the flavor is used to represent the data in a Transferable instance, no additional changes will be made. 
             representationClass = String
     mimeType           = "text/html"

      • allHtmlFlavor

        public static DataFlavor allHtmlFlavor
        Represents a piece of an HTML markup. If possible, the markup received from a native system is supplemented with additional tags to make up a well-formed HTML document. If the flavor is used to represent the data in a Transferable instance, no additional changes will be made. 
             representationClass = String
     mimeType           = "text/html"

    • Constructor Detail

      • DataFlavor

        public DataFlavor()
        Constructs a new DataFlavor. This constructor is provided only for the purpose of supporting the Externalizable interface. It is not intended for public (client) use.
        Since:
        1.2

      • DataFlavor

        public DataFlavor(Class<?> representationClass,
                  String humanPresentableName)
        Constructs a DataFlavor that represents a Java class.

        The returned DataFlavor will have the following characteristics: 

            representationClass = representationClass
    mimeType            = application/x-java-serialized-object
        Parameters:
        representationClass - the class used to transfer data in this flavor
        humanPresentableName - the human-readable string used to identify this flavor; if this parameter is null then the value of the the MIME Content Type is used
        Throws:
        NullPointerException - if representationClass is null

      • DataFlavor

        public DataFlavor(String mimeType,
                  String humanPresentableName)
        Constructs a DataFlavor that represents a MimeType.

        The returned DataFlavor will have the following characteristics:

        If the mimeType is "application/x-java-serialized-object; class=<representation class>", the result is the same as calling new DataFlavor(Class:forName(<representation class>).

        Otherwise: 

             representationClass = InputStream
     mimeType            = mimeType
        Parameters:
        mimeType - the string used to identify the MIME type for this flavor; if the the mimeType does not specify a "class=" parameter, or if the class is not successfully loaded, then an IllegalArgumentException is thrown
        humanPresentableName - the human-readable string used to identify this flavor; if this parameter is null then the value of the the MIME Content Type is used
        Throws:
        IllegalArgumentException - if mimeType is invalid or if the class is not successfully loaded
        NullPointerException - if mimeType is null

      • DataFlavor

        public DataFlavor(String mimeType,
                  String humanPresentableName,
                  ClassLoader classLoader)
           throws ClassNotFoundException
        Constructs a DataFlavor that represents a MimeType.

        The returned DataFlavor will have the following characteristics:

        If the mimeType is "application/x-java-serialized-object; class=<representation class>", the result is the same as calling new DataFlavor(Class:forName(<representation class>).

        Otherwise: 

             representationClass = InputStream
     mimeType            = mimeType
        Parameters:
        mimeType - the string used to identify the MIME type for this flavor
        humanPresentableName - the human-readable string used to identify this flavor
        classLoader - the class loader to use
        Throws:
        ClassNotFoundException - if the class is not loaded
        IllegalArgumentException - if mimeType is invalid
        NullPointerException - if mimeType is null

      • DataFlavor

        public DataFlavor(String mimeType)
           throws ClassNotFoundException
        Constructs a DataFlavor from a mimeType string. The string can specify a "class=<fully specified Java class name>" parameter to create a DataFlavor with the desired representation class. If the string does not contain "class=" parameter, java.io.InputStream is used as default.
        Parameters:
        mimeType - the string used to identify the MIME type for this flavor; if the class specified by "class=" parameter is not successfully loaded, then an ClassNotFoundException is thrown
        Throws:
        ClassNotFoundException - if the class is not loaded
        IllegalArgumentException - if mimeType is invalid
        NullPointerException - if mimeType is null

    • Method Detail

      • tryToLoadClass

        protected static final Class<?> tryToLoadClass(String className,
                                               ClassLoader fallback)
                                        throws ClassNotFoundException
        Tries to load a class from: the bootstrap loader, the system loader, the context loader (if one is present) and finally the loader specified.
        Parameters:
        className - the name of the class to be loaded
        fallback - the fallback loader
        Returns:
        the class loaded
        Throws:
        ClassNotFoundException - if class is not found

      • toString

        public String toString()
        String representation of this DataFlavor and its parameters. The resulting String contains the name of the DataFlavor class, this flavor's MIME type, and its representation class. If this flavor has a primary MIME type of "text", supports the charset parameter, and has an encoded representation, the flavor's charset is also included. See selectBestTextFlavor for a list of text flavors which support the charset parameter.
        Overrides:
        toString in class  Object
        Returns:
        string representation of this DataFlavor
        See Also:
        selectBestTextFlavor(java.awt.datatransfer.DataFlavor[])

      • getTextPlainUnicodeFlavor

        public static final DataFlavor getTextPlainUnicodeFlavor()
        Returns a DataFlavor representing plain text with Unicode encoding, where: 
             representationClass = java.io.InputStream
     mimeType            = "text/plain;
                            charset=<platform default Unicode encoding>"
        Sun's implementation for Microsoft Windows uses the encoding utf-16le. Sun's implementation for Solaris and Linux uses the encoding iso-10646-ucs-2.
        Returns:
        a DataFlavor representing plain text with Unicode encoding
        Since:
        1.3

      • selectBestTextFlavor

        public static final DataFlavor selectBestTextFlavor(DataFlavor[] availableFlavors)
        Selects the best text DataFlavor from an array of DataFlavors. Only DataFlavor.stringFlavor, and equivalent flavors, and flavors that have a primary MIME type of "text", are considered for selection.

        Flavors are first sorted by their MIME types in the following order:

        • "text/sgml"
        • "text/xml"
        • "text/html"
        • "text/rtf"
        • "text/enriched"
        • "text/richtext"
        • "text/uri-list"
        • "text/tab-separated-values"
        • "text/t140"
        • "text/rfc822-headers"
        • "text/parityfec"
        • "text/directory"
        • "text/css"
        • "text/calendar"
        • "application/x-java-serialized-object"
        • "text/plain"
        • "text/<other>"

        For example, "text/sgml" will be selected over "text/html", and DataFlavor.stringFlavor will be chosen over DataFlavor.plainTextFlavor.

        If two or more flavors share the best MIME type in the array, then that MIME type will be checked to see if it supports the charset parameter.

        The following MIME types support, or are treated as though they support, the charset parameter:

        • "text/sgml"
        • "text/xml"
        • "text/html"
        • "text/enriched"
        • "text/richtext"
        • "text/uri-list"
        • "text/directory"
        • "text/css"
        • "text/calendar"
        • "application/x-java-serialized-object"
        • "text/plain"
        The following MIME types do not support, or are treated as though they do not support, the charset parameter:
        • "text/rtf"
        • "text/tab-separated-values"
        • "text/t140"
        • "text/rfc822-headers"
        • "text/parityfec"
        For "text/<other>" MIME types, the first time the JRE needs to determine whether the MIME type supports the charset parameter, it will check whether the parameter is explicitly listed in an arbitrarily chosen DataFlavor which uses that MIME type. If so, the JRE will assume from that point on that the MIME type supports the charset parameter and will not check again. If the parameter is not explicitly listed, the JRE will assume from that point on that the MIME type does not support the charset parameter and will not check again. Because this check is performed on an arbitrarily chosen DataFlavor, developers must ensure that all DataFlavors with a "text/<other>" MIME type specify the charset parameter if it is supported by that MIME type. Developers should never rely on the JRE to substitute the platform's default charset for a "text/<other>" DataFlavor. Failure to adhere to this restriction will lead to undefined behavior.

        If the best MIME type in the array does not support the charset parameter, the flavors which share that MIME type will then be sorted by their representation classes in the following order: java.io.InputStream, java.nio.ByteBuffer, [B, <all others>.

        If two or more flavors share the best representation class, or if no flavor has one of the three specified representations, then one of those flavors will be chosen non-deterministically.

        If the best MIME type in the array does support the charset parameter, the flavors which share that MIME type will then be sorted by their representation classes in the following order: java.io.Reader, java.lang.String, java.nio.CharBuffer, [C, <all others>.

        If two or more flavors share the best representation class, and that representation is one of the four explicitly listed, then one of those flavors will be chosen non-deterministically. If, however, no flavor has one of the four specified representations, the flavors will then be sorted by their charsets. Unicode charsets, such as "UTF-16", "UTF-8", "UTF-16BE", "UTF-16LE", and their aliases, are considered best. After them, the platform default charset and its aliases are selected. "US-ASCII" and its aliases are worst. All other charsets are chosen in alphabetical order, but only charsets supported by this implementation of the Java platform will be considered.

        If two or more flavors share the best charset, the flavors will then again be sorted by their representation classes in the following order: java.io.InputStream, java.nio.ByteBuffer, [B, <all others>.

        If two or more flavors share the best representation class, or if no flavor has one of the three specified representations, then one of those flavors will be chosen non-deterministically.

        Parameters:
        availableFlavors - an array of available DataFlavors
        Returns:
        the best (highest fidelity) flavor according to the rules specified above, or null, if availableFlavors is null, has zero length, or contains no text flavors
        Since:
        1.3

      • getReaderForText

        public Reader getReaderForText(Transferable transferable)
                        throws UnsupportedFlavorException,
                               IOException
        Gets a Reader for a text flavor, decoded, if necessary, for the expected charset (encoding). The supported representation classes are java.io.Reader, java.lang.String, java.nio.CharBuffer, [C, java.io.InputStream, java.nio.ByteBuffer, and [B.

        Because text flavors which do not support the charset parameter are encoded in a non-standard format, this method should not be called for such flavors. However, in order to maintain backward-compatibility, if this method is called for such a flavor, this method will treat the flavor as though it supports the charset parameter and attempt to decode it accordingly. See selectBestTextFlavor for a list of text flavors which do not support the charset parameter.

        Parameters:
        transferable - the Transferable whose data will be requested in this flavor
        Returns:
        a Reader to read the Transferable's data
        Throws:
        IllegalArgumentException - if the representation class is not one of the seven listed above
        IllegalArgumentException - if the Transferable has null data
        NullPointerException - if the Transferable is null
        UnsupportedEncodingException - if this flavor's representation is java.io.InputStream, java.nio.ByteBuffer, or [B and this flavor's encoding is not supported by this implementation of the Java platform
        UnsupportedFlavorException - if the Transferable does not support this flavor
        IOException - if the data cannot be read because of an I/O error
        Since:
        1.3
        See Also:
        selectBestTextFlavor(java.awt.datatransfer.DataFlavor[])

      • getMimeType

        public String getMimeType()
        Returns the MIME type string for this DataFlavor.
        Returns:
        the MIME type string for this flavor

      • getRepresentationClass

        public Class<?> getRepresentationClass()
        Returns the Class which objects supporting this DataFlavor will return when this DataFlavor is requested.
        Returns:
        the Class which objects supporting this DataFlavor will return when this DataFlavor is requested

      • getHumanPresentableName

        public String getHumanPresentableName()
        Returns the human presentable name for the data format that this DataFlavor represents. This name would be localized for different countries.
        Returns:
        the human presentable name for the data format that this DataFlavor represents

      • getPrimaryType

        public String getPrimaryType()
        Returns the primary MIME type for this DataFlavor.
        Returns:
        the primary MIME type of this DataFlavor

      • getSubType

        public String getSubType()
        Returns the sub MIME type of this DataFlavor.
        Returns:
        the Sub MIME type of this DataFlavor

      • getParameter

        public String getParameter(String paramName)
        Returns the human presentable name for this DataFlavor if paramName equals "humanPresentableName". Otherwise returns the MIME type value associated with paramName.
        Parameters:
        paramName - the parameter name requested
        Returns:
        the value of the name parameter, or null if there is no associated value

      • setHumanPresentableName

        public void setHumanPresentableName(String humanPresentableName)
        Sets the human presentable name for the data format that this DataFlavor represents. This name would be localized for different countries.
        Parameters:
        humanPresentableName - the new human presentable name

      • equals

        public boolean equals(Object o)
        Indicates whether some other object is "equal to" this one.

        The equals method implements an equivalence relation on non-null object references:

        • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
        • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
        • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
        • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
        • For any non-null reference value x, x.equals(null) should return false.

        The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

        Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

        The equals comparison for the DataFlavor class is implemented as follows: Two DataFlavors are considered equal if and only if their MIME primary type and subtype and representation class are equal. Additionally, if the primary type is "text", the subtype denotes a text flavor which supports the charset parameter, and the representation class is not java.io.Reader, java.lang.String, java.nio.CharBuffer, or [C, the charset parameter must also be equal. If a charset is not explicitly specified for one or both DataFlavors, the platform default encoding is assumed. See selectBestTextFlavor for a list of text flavors which support the charset parameter.

        Overrides:
        equals in class  Object
        Parameters:
        o - the Object to compare with this
        Returns:
        true if that is equivalent to this DataFlavor; false otherwise
        See Also:
        selectBestTextFlavor(java.awt.datatransfer.DataFlavor[])

      • equals

        @Deprecated
public boolean equals(String s)
        Deprecated.  As inconsistent with hashCode() contract, use isMimeTypeEqual(String) instead.
        Compares only the mimeType against the passed in String and representationClass is not considered in the comparison. If representationClass needs to be compared, then equals(new DataFlavor(s)) may be used.
        Parameters:
        s - the mimeType to compare.
        Returns:
        true if the String (MimeType) is equal; false otherwise or if s is null

      • hashCode

        public int hashCode()
        Returns hash code for this DataFlavor. For two equal DataFlavors, hash codes are equal. For the String that matches DataFlavor.equals(String), it is not guaranteed that DataFlavor's hash code is equal to the hash code of the String.
        Overrides:
        hashCode in class  Object
        Returns:
        a hash code for this DataFlavor
        See Also:
        Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

      • isMimeTypeEqual

        public boolean isMimeTypeEqual(String mimeType)
        Returns whether the string representation of the MIME type passed in is equivalent to the MIME type of this DataFlavor. Parameters are not included in the comparison.
        Parameters:
        mimeType - the string representation of the MIME type
        Returns:
        true if the string representation of the MIME type passed in is equivalent to the MIME type of this DataFlavor; false otherwise
        Throws:
        NullPointerException - if mimeType is null

      • isMimeTypeEqual

        public final boolean isMimeTypeEqual(DataFlavor dataFlavor)
        Compares the mimeType of two DataFlavor objects. No parameters are considered.
        Parameters:
        dataFlavor - the DataFlavor to be compared
        Returns:
        true if the MimeTypes are equal, otherwise false

      • isMimeTypeSerializedObject

        public boolean isMimeTypeSerializedObject()
        Does the DataFlavor represent a serialized object?

      • getDefaultRepresentationClass

        public final Class<?> getDefaultRepresentationClass()

      • getDefaultRepresentationClassAsString

        public final String getDefaultRepresentationClassAsString()

      • isRepresentationClassInputStream

        public boolean isRepresentationClassInputStream()
        Does the DataFlavor represent a java.io.InputStream?

      • isRepresentationClassReader

        public boolean isRepresentationClassReader()
        Returns whether the representation class for this DataFlavor is java.io.Reader or a subclass thereof.
        Since:
        1.4

      • isRepresentationClassCharBuffer

        public boolean isRepresentationClassCharBuffer()
        Returns whether the representation class for this DataFlavor is java.nio.CharBuffer or a subclass thereof.
        Since:
        1.4

      • isRepresentationClassByteBuffer

        public boolean isRepresentationClassByteBuffer()
        Returns whether the representation class for this DataFlavor is java.nio.ByteBuffer or a subclass thereof.
        Since:
        1.4

      • isRepresentationClassSerializable

        public boolean isRepresentationClassSerializable()
        Returns true if the representation class can be serialized.
        Returns:
        true if the representation class can be serialized

      • isRepresentationClassRemote

        public boolean isRepresentationClassRemote()
        Returns true if the representation class is Remote.
        Returns:
        true if the representation class is Remote

      • isFlavorSerializedObjectType

        public boolean isFlavorSerializedObjectType()
        Returns true if the DataFlavor specified represents a serialized object.
        Returns:
        true if the DataFlavor specified represents a Serialized Object

      • isFlavorRemoteObjectType

        public boolean isFlavorRemoteObjectType()
        Returns true if the DataFlavor specified represents a remote object.
        Returns:
        true if the DataFlavor specified represents a Remote Object

      • isFlavorJavaFileListType

        public boolean isFlavorJavaFileListType()
        Returns true if the DataFlavor specified represents a list of file objects.
        Returns:
        true if the DataFlavor specified represents a List of File objects

      • isFlavorTextType

        public boolean isFlavorTextType()
        Returns whether this DataFlavor is a valid text flavor for this implementation of the Java platform. Only flavors equivalent to DataFlavor.stringFlavor and DataFlavors with a primary MIME type of "text" can be valid text flavors.

        If this flavor supports the charset parameter, it must be equivalent to DataFlavor.stringFlavor, or its representation must be java.io.Reader, java.lang.String, java.nio.CharBuffer, [C, java.io.InputStream, java.nio.ByteBuffer, or [B. If the representation is java.io.InputStream, java.nio.ByteBuffer, or [B, then this flavor's charset parameter must be supported by this implementation of the Java platform. If a charset is not specified, then the platform default charset, which is always supported, is assumed.

        If this flavor does not support the charset parameter, its representation must be java.io.InputStream, java.nio.ByteBuffer, or [B.

        See selectBestTextFlavor for a list of text flavors which support the charset parameter.

        Returns:
        true if this DataFlavor is a valid text flavor as described above; false otherwise
        Since:
        1.4
        See Also:
        selectBestTextFlavor(java.awt.datatransfer.DataFlavor[])

      • clone

        public Object clone()
             throws CloneNotSupportedException
        Returns a clone of this DataFlavor.
        Overrides:
        clone in class  Object
        Returns:
        a clone of this DataFlavor
        Throws:
        CloneNotSupportedException - if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.
        See Also:
        Cloneable

      • normalizeMimeTypeParameter

        @Deprecated
protected String normalizeMimeTypeParameter(String parameterName,
                                                        String parameterValue)
        Deprecated. 
        Called on DataFlavor for every MIME Type parameter to allow DataFlavor subclasses to handle special parameters like the text/plain charset parameters, whose values are case insensitive. (MIME type parameter values are supposed to be case sensitive.

        This method is called for each parameter name/value pair and should return the normalized representation of the parameterValue. This method is never invoked by this implementation from 1.1 onwards.

      • normalizeMimeType

        @Deprecated
protected String normalizeMimeType(String mimeType)
        Deprecated. 
        Called for each MIME type string to give DataFlavor subtypes the opportunity to change how the normalization of MIME types is accomplished. One possible use would be to add default parameter/value pairs in cases where none are present in the MIME type string passed in. This method is never invoked by this implementation from 1.1 onwards.