XMLReferenceResolver.java

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/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.xml;
 
import javolution.text.CharArray;
import javolution.text.TextBuilder;
import javolution.util.FastMap;
import javolution.util.FastTable;
import javolution.util.Index;
import javolution.util.function.Equalities;
import javolution.xml.stream.XMLStreamException;
 
public class XMLReferenceResolver {
 
    private FastMap<Object, Index> _objectToId = new FastMap<Object, Index>(
            Equalities.IDENTITY);
 
    private FastTable<Object> _idToObject = new FastTable<Object>();
 
    private int _counter;
 
    private String _idName = "id";
 
    private String _idURI = null;
 
    private String _refName = "ref";
 
    private String _refURI = null;
 
    public XMLReferenceResolver() {}
 
    public void setIdentifierAttribute(String name) {
        setIdentifierAttribute(name, null);
    }
 
    public void setIdentifierAttribute(String localName, String uri) {
        _idName = localName;
        _idURI = uri;
    }
 
    public void setReferenceAttribute(String name) {
        setReferenceAttribute(name, null);
    }
 
    public void setReferenceAttribute(String localName, String uri) {
        _refName = localName;
        _refURI = uri;
    }
 
    public boolean writeReference(Object obj, XMLFormat.OutputElement xml)
            throws XMLStreamException {
        Index id = (Index) _objectToId.get(obj);
        if (id == null) { // New identifier.
            id = Index.valueOf(_counter++);
            _objectToId.put(obj, id);
            _tmp.clear().append(id.intValue());
            if (_idURI == null) {
                xml.getStreamWriter().writeAttribute(_idName, _tmp);
            } else {
                xml.getStreamWriter().writeAttribute(_idURI, _idName, _tmp);
            }
            return false;
        }
        _tmp.clear().append(id.intValue());
        if (_refURI == null) {
            xml._writer.writeAttribute(_refName, _tmp);
        } else {
            xml._writer.writeAttribute(_refURI, _refName, _tmp);
        }
        return true;
    }
 
    private TextBuilder _tmp = new TextBuilder();
 
    public Object readReference(XMLFormat.InputElement xml)
            throws XMLStreamException {
        CharArray value = xml._reader.getAttributeValue(_refURI, _refName);
        if (value == null)
            return null;
        int ref = value.toInt();
        if (ref >= _idToObject.size())
            throw new XMLStreamException("Reference: " + value + " not found");
        return _idToObject.get(ref);
    }
 
    public void createReference(Object obj, XMLFormat.InputElement xml)
            throws XMLStreamException {
        CharArray value = xml._reader.getAttributeValue(_idURI, _idName);
        if (value == null)
            return;
        int i = value.toInt();
        if (_idToObject.size() != i)
            throw new XMLStreamException("Identifier discontinuity detected "
                    + "(expected " + _idToObject.size() + " found " + i + ")");
        _idToObject.add(obj);
    }
 
    public void reset() {
        _idName = "id";
        _idURI = null;
        _refName = "ref";
        _refURI = null;
        _idToObject.clear();
        _objectToId.clear();
        _counter = 0;
    }
 
}