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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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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 {@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 );
    }

}