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package com.sun.org.apache.xpath.internal.jaxp;

import javax.xml.transform.TransformerException;
import javax.xml.xpath.XPathVariableResolver;

import com.sun.org.apache.xml.internal.utils.QName;
import com.sun.org.apache.xpath.internal.VariableStack;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XObject;

import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
import com.sun.org.apache.xalan.internal.res.XSLMessages;


Overrides VariableStack and delegates the call to XPathVariableResolver. 
Author:
Ramesh Mandava/**
 * Overrides {@link VariableStack} and delegates the call to
 * {@link javax.xml.xpath.XPathVariableResolver}.
 *
 * @author Ramesh Mandava
 */
public class JAXPVariableStack extends VariableStack {

    private final XPathVariableResolver resolver;

    public JAXPVariableStack(XPathVariableResolver resolver) {
        this.resolver = resolver;
    }

    public XObject getVariableOrParam(XPathContext xctxt, QName qname)
        throws TransformerException,IllegalArgumentException {
        if ( qname == null ) {
            //JAXP 1.3 spec says that if variable name is null then
            // we need to through IllegalArgumentException
            String fmsg = XSLMessages.createXPATHMessage(
                XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
                new Object[] {"Variable qname"} );
            throw new IllegalArgumentException( fmsg );
        }
        javax.xml.namespace.QName name =
            new javax.xml.namespace.QName(
                qname.getNamespace(),
                qname.getLocalPart());
        Object varValue = resolver.resolveVariable( name );
        if ( varValue == null ) {
            String fmsg = XSLMessages.createXPATHMessage(
                XPATHErrorResources.ER_RESOLVE_VARIABLE_RETURNS_NULL,
                new Object[] { name.toString()} );
            throw new TransformerException( fmsg );
        }
        return XObject.create( varValue, xctxt );
    }

}