* eXist Open Source Native XML Database

* Copyright (C) 2001-2009 The eXist Project

* http://exist-db.org

*

* This program is free software; you can redistribute it and/or

* modify it under the terms of the GNU Lesser General Public License

* as published by the Free Software Foundation; either version 2

* of the License, or (at your option) any later version.

* 

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

* GNU Lesser General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public License

* along with this program; if not, write to the Free Software Foundation

* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

* 

*  $Id$

*/

* @author Wolfgang Meier (wolfgang@exist-db.org)

*/

 

  protected static final String FUNCTION_DESCRIPTION_0_PARAM =

    "Returns the root of the tree to which the context item belongs. ";

  protected static final String FUNCTION_DESCRIPTION_1_PARAM =

    "Returns the root of the tree to which $arg belongs. " +

    "This will usually, but not necessarily, be a document node.\n\n" +

    "If $arg is the empty sequence, the empty sequence is returned.\n\n" +

    "If $arg is a document node, $arg is returned.\n\n" +

    " The behavior of the zero argument version of the function is " +

        "exactly the same as if the context item had been passed in $arg.";

   

    public final static FunctionSignature signatures[] = {

        new FunctionSignature(

                new QName("root", Function.BUILTIN_FUNCTION_NS),

                FUNCTION_DESCRIPTION_0_PARAM,

                new SequenceType[0],

                new FunctionReturnSequenceType(Type.NODE, Cardinality.EXACTLY_ONE, "the root node of the tree to which the context node belongs")

                ),

        new FunctionSignature(

                new QName("root", Function.BUILTIN_FUNCTION_NS),

                FUNCTION_DESCRIPTION_1_PARAM,

                new SequenceType[] { new FunctionParameterSequenceType("arg", Type.NODE, Cardinality.ZERO_OR_ONE, "The input node") },

                new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_ONE, "the root node of the tree to which $arg belongs")

                )

    };

   

    /**

     * @param context

     * @param signature

     */

    public FunRoot(XQueryContext context, FunctionSignature signature) {

        super(context, signature);

    }

   

        /* (non-Javadoc)

         * @see org.exist.xquery.Expression#eval(org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)

         */

    public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {

        if (context.getProfiler().isEnabled()) {

            context.getProfiler().start(this);

            context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));

            if (contextSequence != null)

                {context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);}

            if (contextItem != null)

                {context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());}

        }

       

       

        Sequence seq;

        Sequence result;

        Item item;

        if (contextItem != null)

          {contextSequence = contextItem.toSequence();}

    if (contextSequence == null || contextSequence.isEmpty())

      {result = Sequence.EMPTY_SEQUENCE;}           

       

    //If we have one argumment, we take it into account

    if (getSignature().getArgumentCount() > 0)

      {seq = getArgument(0).eval(contextSequence, contextItem);}

    //Otherwise, we take the context sequence and we iterate over it

    else

      {seq = contextSequence;}

   

    if (seq == null)

      {throw new XPathException(this, ErrorCodes.XPDY0002, "Undefined context item");}

        if (seq.isPersistentSet())

            {result = new ExtArrayNodeSet(seq.getItemCount());}

        else

            {result = new ValueSequence(seq.getItemCount());}

    for (final SequenceIterator i = seq.iterate(); i.hasNext(); ) {

      item = i.nextItem();

            if (!Type.subTypeOf(item.getType(), Type.NODE))

                {throw new XPathException(this, ErrorCodes.XPTY0004,  "Item is not a node; got '" + item + "'", seq);}

            final Sequence s = item.toSequence();

            if (s.isPersistentSet()) {

                final NodeProxy p = s.toNodeSet().get(0);

                result.add(new NodeProxy(p.getDocument()));

            } else {

                if (seq.hasOne() && item.getType() == Type.ATTRIBUTE) {

                  result.add(item);

                } else {

                  result.add(((NodeImpl)item).getDocument());

                }

            }

    }

   

      if (context.getProfiler().isEnabled())

              {context.getProfiler().end(this, "", result);}   

       

        return result;

       

    } 

 

}