SetAttribute.java

/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-09 Wolfgang M. Meier
 *  wolfgang@exist-db.org
 *  http://exist.sourceforge.net
 *  
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.functions.request;

import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.http.servlets.RequestWrapper;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.Variable;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.JavaObjectValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;

/**
 * @author wolf
 */
public class SetAttribute extends Function {
	
	protected static final Logger logger = Logger.getLogger(SetAttribute.class);
	
	public final static FunctionSignature signature =
		new FunctionSignature(
			new QName( "set-attribute", RequestModule.NAMESPACE_URI, RequestModule.PREFIX ),
			"Stores a value in the current request using the supplied attribute name.",
			new SequenceType[] {
				new FunctionParameterSequenceType( "name", Type.STRING, Cardinality.EXACTLY_ONE, "The attribute name" ),
				new FunctionParameterSequenceType( "value", Type.ITEM, Cardinality.ZERO_OR_MORE, "The attribute value" )
				},
			new SequenceType( Type.ITEM, Cardinality.EMPTY )
		);
	
	public SetAttribute(XQueryContext context) 
	{
		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() );
			}
		}
		
		RequestModule myModule = (RequestModule)context.getModule( RequestModule.NAMESPACE_URI );
		
		// request object is read from global variable $request
		Variable var = myModule.resolveVariable( RequestModule.REQUEST_VAR );
		
		if( var == null || var.getValue() == null ) {
			throw( new XPathException( this, "Request not set" ) );
		}

		if( var.getValue().getItemType() != Type.JAVA_OBJECT ) {
			throw( new XPathException( this, "Variable $request is not bound to a Java object." ) );
		}

		JavaObjectValue request = (JavaObjectValue)var.getValue().itemAt( 0 );
		
		// get attribute name parameter
		String attribName 		= getArgument( 0 ).eval( contextSequence, contextItem ).getStringValue();
		Sequence attribValue 	= getArgument( 1 ).eval( contextSequence, contextItem );
		
		if( request.getObject() instanceof RequestWrapper ) {
			((RequestWrapper)request.getObject()).setAttribute( attribName, attribValue );
		} else {
			throw(  new XPathException( this, "Type error: variable $request is not bound to a request object" ) );
		}

		return( Sequence.EMPTY_SEQUENCE );
	}
}