StyleHistoryListModel.java

/***************************************************
*
* cismet GmbH, Saarbruecken, Germany
*
*              ... and it just works.
*
****************************************************/
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package de.cismet.cismap.commons.featureservice.style;

import org.apache.log4j.Logger;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;

import java.io.File;

import java.util.Vector;

import javax.swing.ListModel;
import javax.swing.event.ListDataListener;

import de.cismet.cismap.commons.ConvertableToXML;

/**
 * The StyleHistoryListModel is a ListModel that contains a list of Style-objects.
 *
 * @author   nh
 * @version  $Revision$, $Date$
 */
public class StyleHistoryListModel implements ListModel, ConvertableToXML {

    //~ Static fields/initializers ---------------------------------------------

    /* Maximum number of styles stored in the listmodel */
    private static final int MAX_STYLES = 15;
    /* Name of the root-element of the listmodel as JDOM-element */
    public static final String STYLE_ROOT = "StyleHistory"; // NOI18N

    //~ Instance fields --------------------------------------------------------

    private final Logger logger = Logger.getLogger(StyleHistoryListModel.class);
    /* vector that contains the styles */
    private Vector<Style> styleList;
    /* JDOM-parser */
    private SAXBuilder builder = new SAXBuilder();

    //~ Constructors -----------------------------------------------------------

    /**
     * Constructor with empty stylelist.
     */
    public StyleHistoryListModel() {
        this.styleList = new Vector<Style>();
        this.styleList.ensureCapacity(MAX_STYLES);
    }

    /**
     * Constructor that creates a list of styles from the delivered XML-file.
     *
     * @param   f  doc JDOM-Document das die History beinhält
     *
     * @throws  Exception  DOCUMENT ME!
     */
    public StyleHistoryListModel(final File f) throws Exception {
        this();

        try {
            final Document doc = builder.build(f);
            final Element root = doc.getRootElement();
            if ((root != null) && root.getName().equals(STYLE_ROOT)) {
                this.initFromElement(root);
            } else {
                logger.error("file '" + f.getName() + "' contains wrong xml content:\n" + doc); // NOI18N
            }
        } catch (Exception ex) {
            logger.error("Could not load style history from '" + f.getName() + "'", ex);        // NOI18N
        }
    }

    //~ Methods ----------------------------------------------------------------

    /**
     * Adds a Style to the listmodel. If the model contains more than the allowed maximum the oldest style will be
     * dropped.
     *
     * @param  newStyle  e the style to add
     */
    public void addStyle(final Style newStyle) {
        if (!elementEquals(newStyle)) {
            styleList.add(newStyle);
            if (styleList.size() > MAX_STYLES) {
                styleList.remove(0);
            }
        }
    }

    /**
     * Returns the style from a specific position inside the stylelist.
     *
     * @param   index  position of the desired style
     *
     * @return  object (instanceof Style)
     */
    @Override
    public Object getElementAt(final int index) {
        return styleList.get(index);
    }

    /**
     * Returns the current count of saved styles.
     *
     * @return  DOCUMENT ME!
     */
    @Override
    public int getSize() {
        return styleList.size();
    }

    /**
     * Deletes all saved styles.
     */
    public void clear() {
        styleList.clear();
    }

    /**
     * Checks if there's already an equal style inside the stylelist.
     *
     * @param   compare  Style that should be compared with the list
     *
     * @return  true if there's already an equal style, else false
     */
    public boolean elementEquals(final Style compare) {
        if (styleList.isEmpty()) {
            return false;
        } else {
            boolean returnValue = false;
            for (final Style s : styleList) {
                if (s.compareTo(compare) == 0) {
                    returnValue = true;
                    break;
                }
            }
            return returnValue;
        }
    }

    /**
     * Returns this model as JDOM-element with all styles as children.
     *
     * @return  DOCUMENT ME!
     */
    @Override
    public Element toElement() {
        final Element e = new Element(STYLE_ROOT);
        for (final Style s : styleList) {
            e.addContent(s.toElement());
        }
        return e;
    }

    @Override
    public void addListDataListener(final ListDataListener l) {
    }

    @Override
    public void removeListDataListener(final ListDataListener l) {
    }

    @Override
    public void initFromElement(final Element element) throws Exception {
        this.styleList.clear();
        this.styleList.ensureCapacity(element.getChildren(Style.STYLE_ELEMENT).size());
        for (final Object o : element.getChildren(Style.STYLE_ELEMENT)) {
            if (o instanceof Element) {
                final Style newStyle = new BasicStyle((Element)o);
                if (newStyle != null) {
                    this.styleList.add(newStyle);
                }
            }
        }
    }
}