Interface IContentDescription


  • public interface IContentDescription
    A content description object contains information about the nature of arbitrary data.

    A content description object will always include the content type for the examined contents, and may also include information on:

    1. charset;
    2. byte order mark;
    3. other custom properties provided by third-party plug-ins.

    Content describers provided by plug-ins will fill in most of the properties in a content description object, except for the content type, what is done by the platform. After a content description is filled in by a content interpreter, it is marked as immutable by the platform, so calling any of the mutator methods defined in this interface will cause an IllegalStateException to be thrown.

    Default values for properties can be contributed by plug-ins as part of the content type definition markup.

    This interface is not intended to be implemented by clients.

    Since:
    3.0
    See Also:
    IContentDescriber
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static QualifiedName[] ALL
      Options constant meaning that all properties should be described.
      static byte[] BOM_UTF_16BE
      Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-16 Big Endian character encoding scheme.
      static byte[] BOM_UTF_16LE
      Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-16 Little Endian character encoding scheme.
      static byte[] BOM_UTF_8
      Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-8 character encoding scheme.
      static QualifiedName BYTE_ORDER_MARK
      Key for the "byte order mark" property.
      static QualifiedName CHARSET
      Key for the "charset" property.
    • Field Detail

      • CHARSET

        static final QualifiedName CHARSET
        Key for the "charset" property.
      • BYTE_ORDER_MARK

        static final QualifiedName BYTE_ORDER_MARK
        Key for the "byte order mark" property. This property is only meaningful when describing byte streams.
      • ALL

        static final QualifiedName[] ALL
        Options constant meaning that all properties should be described.
      • BOM_UTF_8

        static final byte[] BOM_UTF_8
        Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-8 character encoding scheme.
      • BOM_UTF_16BE

        static final byte[] BOM_UTF_16BE
        Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-16 Big Endian character encoding scheme.
      • BOM_UTF_16LE

        static final byte[] BOM_UTF_16LE
        Constant that identifies the Byte-Order-Mark for contents encoded with the UTF-16 Little Endian character encoding scheme.
    • Method Detail

      • isRequested

        boolean isRequested​(QualifiedName key)
        Returns whether the given property is requested to be described. This method is intended to allow content describers to determine which properties should be described.
        Parameters:
        key - a key for the property to be verified
        Returns:
        true if the property is to be described, false otherwise
      • getCharset

        String getCharset()
        Returns the charset name to be used when reading the contents described by this object.

        If a Unicode byte order mark has been found (the BYTE_ORDER_MARK property has been set), a corresponding charset name will be returned (e.g. "UTF-8", "UTF-16"). Otherwise, the value of the CHARSET property will be returned.

        Returns:
        a charset name, or null
      • getContentType

        IContentType getContentType()
        Returns the content type detected. Returns null if the content type could not be determined.
        Returns:
        the corresponding content type, or null
      • getProperty

        Object getProperty​(QualifiedName key)
        Returns the value of custom property set by the content describer, or the default value for the property, if one has been defined.

        The qualifier part of the property name must be the unique identifier of the declaring plug-in (e.g. "com.example.plugin").

        Parameters:
        key - the property key
        Returns:
        the property value, or null, if the property is not found
      • setProperty

        void setProperty​(QualifiedName key,
                         Object value)
        Sets the given property to the given value.

        The qualifier part of the property name must be the unique identifier of the declaring plug-in (e.g. "com.example.plugin").

        This method should not be called by clients other than content describers. An attempt to set a property from other contexts will cause an IllegalStateException to be thrown.

        Parameters:
        key - the qualified name of the property
        value - the property value, or null, if the property is to be removed
        Throws:
        IllegalStateException - if called after this description has been filled in