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package net.sf.cuf.ui.builder;

import javax.swing.ImageIcon;
import java.net.URL;
import java.util.Map;
import java.util.HashMap;

/**
 * The icon cache is a class that loads icons and stores them in a Map.
 * The next time the same icon is needed, it's taken from the cache.
 * If a icon can't be loaded on the first try, no further access are
 * tried.
 */
public class IconCache
{
    /*
     * icon stuff taken from SwingDecorater, should always be in sync
     */
    /** Suffix for the the icon files */
    public static final String ICON_PREFIX                      = "icons/";
    /** first suffix for the the icon files */
    public static final String ICON_SUFFIX1                     = ".png";
    /** second suffix for the the icon files */
    public static final String ICON_SUFFIX2                     = ".gif";
    /** Suffix for the normal icon */
    public static final String ICON_MODIFIER_NORMAL             = "";
    /** Suffix for the disabled icon */
    public static final String ICON_MODIFIER_DISABLED           = "Disabled";
    /** Suffix for the pressed icon */
    public static final String ICON_MODIFIER_PRESSED            = "Pressed";
    /** Suffix for the selected icon */
    public static final String ICON_MODIFIER_SELECTED           = "Selected";
    /** Suffix for the disabled selected icon */
    public static final String ICON_MODIFIER_DISABLED_SELECTED  = "DisabledSelected";
    /** Suffix for the rollover icon */
    public static final String ICON_MODIFIER_ROLLOVER           = "Rollover";
    /** Suffix for the selected rollover icon */
    public static final String ICON_MODIFIER_ROLLOVER_SELECTED  = "RolloverSelected";
    /** Suffix for the small icon */
    public static final String ICON_MODIFIER_SMALL              = "Small";

    /** cache for our icons */
    private Map mIconCache= new HashMap<>();

    /**
     * Loads an Icon for the handed (relative) name and modifier.
     * If no icon is found, null is returned.
     *
     * @param pName relative name, may be null
     * @param pIconModifier modifier for the icon name
     * @return an ImageIcon or null
     */
    public ImageIcon getIcon(final String pName, final String pIconModifier)
    {
        if (pName==null)
        {
            return null;
        }

        String name1= "/" + ICON_PREFIX +
                      pName +
                      pIconModifier +
                      ICON_SUFFIX1;
        String name2= "/" + ICON_PREFIX +
                      pName +
                      pIconModifier +
                      ICON_SUFFIX2;

        if (mIconCache.containsKey(name1))
        {
            return mIconCache.get(name1);
        }
        if (mIconCache.containsKey(name2))
        {
            return mIconCache.get(name2);
        }

        ImageIcon imageIcon= null;
        try
        {
            URL url= getClass().getResource(name1);
            imageIcon= new ImageIcon(url);
            imageIcon.getImage();
            mIconCache.put(name1, imageIcon);
        }
        catch (Exception ignored1)
        {
            try
            {
                URL url= getClass().getResource(name2);
                imageIcon= new ImageIcon(url);
                imageIcon.getImage();
                mIconCache.put(name2, imageIcon);
            }
            catch (Exception ignored2)
            {
                mIconCache.put(name1, null);
                mIconCache.put(name2, imageIcon);
                // we ignore load problems, and will not try to load the
                // same icon again
            }
        }

        return imageIcon;
    }
}