src/org/apache/xml/dtm/XSequence.java

/*
 * The Apache Software License, Version 1.1
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 * Copyright (c) 1999 The Apache Software Foundation.  All rights
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 *       "This product includes software developed by the
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
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package org.apache.xml.dtm;

import java.util.Vector;


// Xerces XNI post-Schema datatype support
import org.apache.xerces.xni.psvi.ElementPSVI;
import org.apache.xerces.xni.psvi.AttributePSVI;
import org.apache.xerces.xni.psvi.ItemPSVI;
import org.apache.xerces.impl.xs.ElementPSVImpl;
import org.apache.xerces.impl.xs.AttributePSVImpl;
import org.apache.xerces.impl.xs.XSTypeDecl;
import org.apache.xerces.impl.dv.xs.XSSimpleTypeDecl;

/** This interface provides an API representation for the XPath 2 
 * Data Model's "Sequences" -- which are the basic representation 
 * for typed values. Only built-in types, types derived from 
 * built-ins, and sets thereof are returned directly by the XPath2
 * DM; complex schema-types must be accessed through the document tree.
 * 
 * The interface also provides XSequence.EMPTY, an empty sequence,
 * as a manefest constant.
 * */
public interface XSequence 
{
	/** @return the number of members in this sequence. */
	public int getLength();

	/** Retrieve the value for this member of the sequence. Since values may be
	 * a heterogenous mix, and their type may not be known until they're examined,
	 * they're returned as Objects. This is storage-inefficient if the value(s)
	 * is/are builtins that map to Java primitives. Tough.
	 * 
	 * @param index 0-based index into the sequence.
	 * @return the specified value
	 * @throws exception if index <0 or >=length	 
	 * */
	public Object getValue(int index);
			
	/** Retrieve the datatype namespace URI for this member of the sequence.
	 * 
	 * @param index 0-based index into the sequence.
	 * @return the namespace for the specified value's type
	 * @throws exception if index <0 or >=length	 
	 * */
	public String getTypeNS(int index);

	/** Retrieve the datatype namespace URI for this member of the sequence.
	 * 
	 * %REVIEW% Do we really need type -- 
	 * or can we just tell folks to do instanceOf on the Java value objects?	
	 * 
	 * @param index 0-based index into the sequence.
	 * @return the localname of the specified value's type
	 * @throws exception if index <0 or >=length	 
	 * */
	public String getTypeLocalName(int index);

	/** Ask whether this member's datatype equals or is derived from a specified
	 * schema NSURI/localname pair.
	 * 
	 * @param index 0-based index into the sequence.
	 * @return true if the type is an instance of this schema datatype,
	 * false if it isn't.
	 * @throws exception if index <0 or >=length	 
	 * */
	public boolean isSchemaType(int index, String namespace, String localname);

	
	/** MANAFEST CONSTANT: An empty XSequence, which can be returned when no
	 * typed value exists. Implemented as an anonymous class so it can live in
	 * the definition of XSequence itself.
	 * */	
	public static final XSequence EMPTY	= new XSequence()
	{
		/** @return the number of members in this sequence. */
		public int getLength()
		{ return 0;	}

		/** Retrieve the value for this member of the sequence. Since values may be
		 * a heterogenous mix, and their type may not be known until they're examined,
		 * they're returned as Objects. This is storage-inefficient if the value(s)
		 * is/are builtins that map to Java primitives. Tough.
		 * 
	 	 * @param index 0-based index into the sequence.
		 * @return the specified value
		 * @throws exception if index <0 or >=length	 
		 * */
		public Object getValue(int index)
		{ throw new java.lang.ArrayIndexOutOfBoundsException(); }
	
		/** Retrieve the datatype namespace URI for this member of the sequence.
		 * 
		 * @param index 0-based index into the sequence.
		 * @return the namespace for the specified value's type
		 * @throws exception if index <0 or >=length	 
		 * */
		public String getTypeNS(int index)
		{ throw new java.lang.ArrayIndexOutOfBoundsException(); }
	
		/** Retrieve the datatype namespace URI for this member of the sequence.
		 * 
		 * %REVIEW% Do we really need type -- 
		 * or can we just tell folks to do instanceOf on the Java value objects?	
		 * 
		 * @param index 0-based index into the sequence.
		 * @return the localname of the specified value's type
		 * @throws exception if index <0 or >=length	 
		 * */
		public String getTypeLocalName(int index)
		{ throw new java.lang.ArrayIndexOutOfBoundsException(); }
	
		/** Ask whether this member's datatype equals or is derived from a specified
		 * schema NSURI/localname pair.
		 * 
		 * @param index 0-based index into the sequence.
		 * @return true if the type is an instance of this schema datatype,
		 * false if it isn't.
		 * @throws exception if index <0 or >=length	 
		 * */
		public boolean isSchemaType(int index, String namespace, String localname)
		{ throw new java.lang.ArrayIndexOutOfBoundsException(); }
	};
}