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// =================================================================================================
// ADOBE SYSTEMS INCORPORATED
// Copyright 2006 Adobe Systems Incorporated
// All Rights Reserved
//
// NOTICE: Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
// =================================================================================================
package com.adobe.internal.xmp;
import java.util.Map;
import com.adobe.internal.xmp.properties.XMPAliasInfo;
/**
* The schema registry keeps track of all namespaces and aliases used in the XMP
* metadata. At initialisation time, the default namespaces and default aliases
* are automatically registered. Namespaces must be registered before
* used in namespace URI parameters or path expressions. Within the XMP Toolkit
* the registered namespace URIs and prefixes must be unique. Additional
* namespaces encountered when parsing RDF are automatically registered. The
* namespace URI should always end in an XML name separator such as '/' or '#'.
* This is because some forms of RDF shorthand catenate a namespace URI with an
* element name to form a new URI.
*
* Aliases in XMP serve the same purpose as Windows file shortcuts,
* Macintosh file aliases, or UNIX file symbolic links. The aliases are simply
* multiple names for the same property. One distinction of XMP aliases is that
* they are ordered, there is an alias name pointing to an actual name. The
* primary significance of the actual name is that it is the preferred name for
* output, generally the most widely recognized name.
*
* The names that can be aliased in XMP are restricted. The alias must be a top
* level property name, not a field within a structure or an element within an
* array. The actual may be a top level property name, the first element within
* a top level array, or the default element in an alt-text array. This does not
* mean the alias can only be a simple property. It is OK to alias a top level
* structure or array to an identical top level structure or array, or to the
* first item of an array of structures.
*
* @author Stefan Makswit
* @version $Revision$
* @since 27.01.2006
*/
public interface XMPSchemaRegistry
{
// ---------------------------------------------------------------------------------------------
// Namespace Functions
/**
* Register a namespace URI with a suggested prefix. It is not an error if
* the URI is already registered, no matter what the prefix is. If the URI
* is not registered but the suggested prefix is in use, a unique prefix is
* created from the suggested one. The actual registeed prefix is always
* returned. The function result tells if the registered prefix is the
* suggested one.
*
* Note: No checking is presently done on either the URI or the prefix.
*
* @param namespaceURI
* The URI for the namespace. Must be a valid XML URI.
* @param suggestedPrefix
* The suggested prefix to be used if the URI is not yet
* registered. Must be a valid XML name.
* @return Returns the registered prefix for this URI, is equal to the
* suggestedPrefix if the namespace hasn't been registered before,
* otherwise the existing prefix.
* @throws XMPException If the parameters are not accordingly set
*/
String registerNamespace(String namespaceURI, String suggestedPrefix) throws XMPException;
/**
* Obtain the prefix for a registered namespace URI.
*
* It is not an error if the namespace URI is not registered.
*
* @param namespaceURI
* The URI for the namespace. Must not be null or the empty
* string.
* @return Returns the prefix registered for this namespace URI or null.
*/
String getNamespacePrefix(String namespaceURI);
/**
* Obtain the URI for a registered namespace prefix.
*
* It is not an error if the namespace prefix is not registered.
*
* @param namespacePrefix
* The prefix for the namespace. Must not be null or the empty
* string.
* @return Returns the URI registered for this prefix or null.
*/
String getNamespaceURI(String namespacePrefix);
/**
* @return Returns the registered prefix/namespace-pairs as map, where the keys are the
* namespaces and the values are the prefixes.
*/
Map getNamespaces();
/**
* @return Returns the registered namespace/prefix-pairs as map, where the keys are the
* prefixes and the values are the namespaces.
*/
Map getPrefixes();
/**
* Deletes a namespace from the registry.
*
* Does nothing if the URI is not registered, or if the namespaceURI
* parameter is null or the empty string.
*
* Note: Not yet implemented.
*
* @param namespaceURI
* The URI for the namespace.
*/
void deleteNamespace(String namespaceURI);
// ---------------------------------------------------------------------------------------------
// Alias Functions
/**
* Determines if a name is an alias, and what it is aliased to.
*
* @param aliasNS
* The namespace URI of the alias. Must not be null or the empty
* string.
* @param aliasProp
* The name of the alias. May be an arbitrary path expression
* path, must not be null or the empty string.
* @return Returns the XMPAliasInfo for the given alias namespace and property or
* null if there is no such alias.
*/
XMPAliasInfo resolveAlias(String aliasNS, String aliasProp);
/**
* Collects all aliases that are contained in the provided namespace.
* If nothing is found, an empty array is returned.
*
* @param aliasNS a schema namespace URI
* @return Returns all alias infos from aliases that are contained in the provided namespace.
*/
XMPAliasInfo[] findAliases(String aliasNS);
/**
* Searches for registered aliases.
*
* @param qname
* an XML conform qname
* @return Returns if an alias definition for the given qname to another
* schema and property is registered.
*/
XMPAliasInfo findAlias(String qname);
/**
* @return Returns the registered aliases as map, where the key is the "qname" (prefix and name)
* and the value an XMPAliasInfo-object.
*/
Map getAliases();
}