/*
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package org.apache.xalan.xsltc.dom;

import org.apache.xalan.xsltc.DOM;
import org.apache.xalan.xsltc.DOMEnhancedForDTM;
import org.apache.xalan.xsltc.StripFilter;
import org.apache.xalan.xsltc.runtime.AbstractTranslet;
import org.apache.xalan.xsltc.runtime.Hashtable;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMWSFilter;

/**
 * A wrapper class that adapts the
 * {@link org.apache.xml.dtm.DTMWSFilter DTMWSFilter} interface to the XSLTC
 * DOM {@link org.apache.xalan.xsltc.StripFilter StripFilter} interface.
 */
public class DOMWSFilter implements DTMWSFilter {

    private AbstractTranslet m_translet;
    private StripFilter m_filter;
    
    // The Hashtable for DTM to mapping array
    private Hashtable m_mappings;
    
    // Cache the DTM and mapping that are used last time
    private DTM m_currentDTM;
    private short[] m_currentMapping;

    /**
     * Construct an adapter connecting the <code>DTMWSFilter</code> interface
     * to the <code>StripFilter</code> interface.
     *
     * @param translet A translet that also implements the StripFilter
     * interface.
     *
     * @see org.apache.xml.dtm.DTMWSFilter
     * @see org.apache.xalan.xsltc.StripFilter
     */
    public DOMWSFilter(AbstractTranslet translet) {
        m_translet = translet;
        m_mappings = new Hashtable();

        if (translet instanceof StripFilter) {
            m_filter = (StripFilter) translet;
        }
    }

    /**
     * Test whether whitespace-only text nodes are visible in the logical
     * view of <code>DTM</code>. Normally, this function
     * will be called by the implementation of <code>DTM</code>;
     * it is not normally called directly from
     * user code.
     *
     * @param node int handle of the node.
     * @param dtm the DTM that owns this node
     * @return one of <code>NOTSTRIP</code>, <code>STRIP</code> or
     * <code>INHERIT</code>.
     */
    public short getShouldStripSpace(int node, DTM dtm) {
        if (m_filter != null && dtm instanceof DOM) {
            DOM dom = (DOM)dtm;
            int type = 0;

            if (dtm instanceof DOMEnhancedForDTM) {
                DOMEnhancedForDTM mappableDOM = (DOMEnhancedForDTM)dtm;
                
                short[] mapping;
                if (dtm == m_currentDTM) {
                    mapping = m_currentMapping;
                }
                else {  
                    mapping = (short[])m_mappings.get(dtm);
                    if (mapping == null) {
                        mapping = mappableDOM.getMapping(
                                     m_translet.getNamesArray(),
                                     m_translet.getUrisArray(),
                                     m_translet.getTypesArray());
                        m_mappings.put(dtm, mapping);
                        m_currentDTM = dtm;
                        m_currentMapping = mapping;
                    }
                }
                
                int expType = mappableDOM.getExpandedTypeID(node);
                
                // %OPT% The mapping array does not have information about all the
                // exptypes. However it does contain enough information about all names
                // in the translet's namesArray. If the expType does not fall into the
                // range of the mapping array, it means that the expType is not for one
                // of the recognized names. In this case we can just set the type to -1.
                if (expType >= 0 && expType < mapping.length)
                  type = mapping[expType];
                else
                  type = -1;
                
            } 
            else {
                return INHERIT;
            }

            if (m_filter.stripSpace(dom, node, type)) {
                return STRIP;
            } else {
                return NOTSTRIP;
            }
        } else {
            return NOTSTRIP;
        }
    }
}
