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/* DocumentFunction.java --

   Copyright (C) 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GNU Classpath 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

General Public License for more details.

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

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package gnu.xml.transform;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import java.util.TreeSet;

import javax.xml.namespace.QName;

import javax.xml.transform.TransformerException;

import javax.xml.transform.dom.DOMSource;

import javax.xml.xpath.XPathFunction;

import javax.xml.xpath.XPathFunctionException;

import org.w3c.dom.Node;

import gnu.xml.xpath.Constant;

import gnu.xml.xpath.Expr;

import gnu.xml.xpath.Function;

import gnu.xml.xpath.IdFunction;

/**

 * The XSLT <code>document()</code>function.

 *

 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>

 */

final class DocumentFunction

  extends Expr

  implements Function, XPathFunction

{

  final Stylesheet stylesheet;

  final Node base;

  List args;

  List values;

  DocumentFunction(Stylesheet stylesheet, Node base)

  {

    this.stylesheet = stylesheet;

    this.base = base;

  }

  public Object evaluate(List args)

    throws XPathFunctionException

  {

    values = args;

    return evaluate(null, 1, 1);

  }

  public void setArguments(List args)

  {

    this.args = args;

  }

  public Object evaluate(Node context, int pos, int len)

  {

    int arity = args.size();

    if (values == null)

      {

        values = new ArrayList(arity);

        for (int i = 0; i < arity; i++)

          {

            Expr arg = (Expr) args.get(i);

            values.add(arg.evaluate(context, pos, len));

          }

      }

    Object ret;

    switch (arity)

      {

      case 1:

        Object arg = values.get(0);

        if (arg instanceof Collection)

          {

            Collection ns = (Collection) arg;

            Collection acc = new TreeSet();

            for (Iterator i = ns.iterator(); i.hasNext(); )

              {

                Node node = (Node) i.next();

                String s = Expr.stringValue(node);

                acc.addAll(document(s, node.getBaseURI()));

              }

            ret = acc;

          }

        else

          {

            String s = Expr._string(context, arg);

            ret = document(s, base.getBaseURI());

          }

        break;

      case 2:

        Object arg1 = values.get(0);

        Object arg2 = values.get(1);

        if (!(arg2 instanceof Collection))

          {

            throw new RuntimeException("second argument is not a node-set");

          }

        Collection arg2ns = (Collection) arg2;

        String base2 = arg2ns.isEmpty() ? null :

          ((Node) arg2ns.iterator().next()).getBaseURI();

        if (arg1 instanceof Collection)

          {

            Collection arg1ns = (Collection) arg1;

            Collection acc = new TreeSet();

            for (Iterator i = arg1ns.iterator(); i.hasNext(); )

              {

                Node node = (Node) i.next();

                String s = Expr.stringValue(node);

                acc.addAll(document(s, base2));

              }

            ret = acc;

          }

        else

          {

            String s = Expr._string(context, arg1);

            ret = document(s, base2);

          }

        break;

      default:

        throw new RuntimeException("invalid arity");

      }

    values = null;

    return ret;

  }

  /**

   * The XSL <code>document</code> function.

   * @see XSLT 12.1

   * @param uri the URI from which to retrieve nodes

   * @param base the base URI for relative URIs

   */

  Collection document(String uri, String base)

  {

    if ("".equals(uri) || uri == null)

      {

        uri = this.base.getBaseURI();

      }

    // Get fragment

    Expr fragment = null;

    int hi = uri.indexOf('#');

    if (hi != -1)

      {

        String f = uri.substring(hi + 1);

        uri = uri.substring(0, hi);

        // TODO handle xpointer() here

        // this only handles IDs

        fragment = new IdFunction(new Constant(f));

      }

    // Get document source

    try

      {

        DOMSource source;

        XSLURIResolver resolver = stylesheet.factory.resolver;

        synchronized (resolver)

          {

            if (stylesheet.transformer != null)

              {

                resolver.setUserResolver(stylesheet.transformer.uriResolver);

                resolver.setUserListener(stylesheet.transformer.errorListener);

              }

            source = resolver.resolveDOM(null, base, uri);

          }

        Node node = source.getNode();

        if (fragment == null)

          {

            return Collections.singleton(node);

          }

        else

          {

            Object ret = fragment.evaluate(node, 1, 1);

            if (!(ret instanceof Collection))

              {

                // XXX Report error?

                return Collections.EMPTY_SET;

              }

            return (Collection) ret;

          }

      }

    catch (TransformerException e)

      {

        String msg = "can't open " + uri;

        if (base != null)

          {

            msg += " with base " + base;

          }

        throw new RuntimeException(msg);

      }

  }

  public Expr clone(Object context)

  {

    Stylesheet s = stylesheet;

    if (context instanceof Stylesheet)

      {

        s = (Stylesheet) context;

      }

    DocumentFunction f = new DocumentFunction(s, base);

    int len = args.size();

    List args2 = new ArrayList(len);

    for (int i = 0; i < len; i++)

      {

        args2.add(((Expr) args.get(i)).clone(context));

      }

    f.setArguments(args2);

    return f;

  }

  public boolean references(QName var)

  {

    for (Iterator i = args.iterator(); i.hasNext(); )

      {

        if (((Expr) i.next()).references(var))

          {

            return true;

          }

      }

    return false;

  }

}