/**
 * This interface provides base level definitions for all metadata components.
 *
 * @version 2.3
 */
public interface Metadata {
    /**
     * Add a vendor extension to this metadata component.
     * 
     * @param vendor Identifier for the vendor
     * @param key The extension key
     * @param value Value for the extension
     * @return The ExtensionMetaData
     */
    ExtensionMetadata newExtensionMetaData(String vendor, String key, String value);

    /**
     * Number of extensions on this component.
     * 
     * @return Number of extensions
     */
    int getNumberOfExtensions();

    /**
     * Accessor for the defined extensions for this component
     * 
     * @return The extensions
     */
    ExtensionMetadata[] getExtensions();

    /**
     * Accessor for the parent metadata component.
     * 
     * @return The parent
     */
    Metadata getParent();
}