/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-06 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;

import org.exist.dom.DocumentSet;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.*;

/**
 * @author wolf
 */
public class AtomicToString extends AbstractExpression {

	Expression expression;

	/**
	 * @param context
	 */
	public AtomicToString(XQueryContext context, Expression expr) {
		super(context);
		this.expression = expr;
	}

	/* (non-Javadoc)
     * @see org.exist.xquery.Expression#analyze(org.exist.xquery.Expression)
     */
    public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
    	contextInfo.setParent(this);
        expression.analyze(contextInfo);
    }
    
	/* (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 {
		Sequence seq = expression.eval(contextSequence, contextItem);
		if(seq.isEmpty())
			return Sequence.EMPTY_SEQUENCE;
		Item next;
		ValueSequence result = new ValueSequence();
		for (SequenceIterator i = seq.iterate(); i.hasNext();) {
			next = i.nextItem();
			result.add(new StringValue(next.getStringValue()));
		}
		return result;
	}

	/* (non-Javadoc)
     * @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
     */
    public void dump(ExpressionDumper dumper) {
        dumper.display("xs:string(");
        expression.dump(dumper);
        dumper.display(")");
    }
    
    public String toString() {
    	StringBuilder result = new StringBuilder();
    	result.append("xs:string(");
    	result.append(expression.toString());
    	result.append(")");
    	return result.toString();
    }    
    
	/* (non-Javadoc)
	 * @see org.exist.xquery.Expression#returnsType()
	 */
	public int returnsType() {
		return Type.STRING;
	}

	/* (non-Javadoc)
	 * @see org.exist.xquery.AbstractExpression#preselect(org.exist.dom.DocumentSet)
	 */
	public DocumentSet preselect(DocumentSet in_docs) throws XPathException {
		return in_docs;
	}

	public void setContextDocSet(DocumentSet contextSet) {
		super.setContextDocSet(contextSet);
		expression.setContextDocSet(contextSet);
	}
	
	/* (non-Javadoc)
	 * @see org.exist.xquery.AbstractExpression#resetState()
	 */
	public void resetState(boolean postOptimization) {
		super.resetState(postOptimization);
		expression.resetState(postOptimization);
	}

}