Jtree getTreeCellRendererComponent execute several times

Question

i've got a problem with a custom TreeCellRenderer. the overridable method getTreeCellRendererComponent is executed about 4 time when i click on a node. Does anybody have an idea about this? Thanks by advance.

Simon

my code:

    @Override
public Component getTreeCellRendererComponent(JTree tree, Object p_value,
        boolean selected, boolean expanded, boolean leaf, int row,
        boolean hasFocus) {
    super.getTreeCellRendererComponent(tree, p_value, selected, expanded,
            leaf, row, hasFocus);
    if (row != -1) {
        DefaultMutableTreeNode aNode = (DefaultMutableTreeNode) p_value;
        TreePath treePath;

        treePath = tree.getPathForRow(row);
        if (treePath == null) {
            return this;
        }
        // int pathCount = treePath.getPathCount();
        JLabel label = (JLabel) this;
        if (aNode.getUserObject() instanceof MlCompteMail) {
            traiteNomCompte((MlCompteMail) aNode.getUserObject(), label);
            // JTreeFactory treeFact = new JTreeFactory();
            // treeFact.refreshNode(treePath);

            return this;
        } else if (aNode.getUserObject() instanceof MlDossier) {
            traiteNomDossier((MlDossier) aNode.getUserObject(), label, leaf);
            // JTreeFactory treeFact = new JTreeFactory();
            // treeFact.refreshNode(treePath);
            return this;
        }
    }

    return this;
}

/**
 * @param value
 * @param treePath
 * @param label
 * @param p_leaf
 */
private void traiteNomDossier(MlDossier p_dossier, JLabel label,
        boolean p_leaf) {
    String nomDossier = p_dossier.getNomDossier();
    if (nomDossier.equals(EnDossierBase.BROUILLON.getLib())) {
        label.setIcon(IconeTreeFactory.getBrouillon());
    } else if (nomDossier.equals(EnDossierBase.CORBEILLE.getLib())) {
        label.setIcon(IconeTreeFactory.getCorbeille());
    } else if (nomDossier.equals(EnDossierBase.ENVOYES.getLib())) {
        label.setIcon(IconeTreeFactory.getEnvoye());
    } else if (nomDossier.equals(EnDossierBase.RECEPTION.getLib())) {
        label.setIcon(IconeTreeFactory.getReception());
    } else if (nomDossier.equals(EnDossierBase.SPAM.getLib())) {
        label.setIcon(IconeTreeFactory.getSpam());
    } else if (p_leaf) {
        label.setIcon(IconeTreeFactory.getDossierFerme());
    } else {
        label.setIcon(IconeTreeFactory.getDossierOuvert());
    }
    int unreadMess = p_dossier.getUnreadMessCount();
    if (unreadMess > 0) {
        label.setText(nomDossier + " (" + unreadMess + ")");
        label.setFont(Fontfactory.getTREE_FONT_GRAS());
    } else {
        label.setText(nomDossier);
        label.setFont(Fontfactory.getTREE_FONT_PLAIN());
    }
    return;
}

// }
// }

/**
 * @param value
 * @param label
 */
private void traiteNomCompte(MlCompteMail p_compteMail, JLabel label) {
    int unreadMess = p_compteMail.getUreadMessCount();
    if (unreadMess > 0) {
        label
                .setText(p_compteMail.getNomCompte() + " (" + unreadMess
                        + ")");
        label.setFont(Fontfactory.getTREE_FONT_GRAS());
    } else {
        label.setText(p_compteMail.getNomCompte());
        label.setFont(Fontfactory.getTREE_FONT_PLAIN());
    }
    label.setIcon(IconeTreeFactory.getDossierOuvert());

}

Answer 1

i found a way to speed up the decoration of my jtree, the jtree use the method "toString()" to paint a node so i have override the method in my two kind of node, so, in my customTreeCellRenderer, i just call the toString method on my userObject and that work. Thanks for your help.

Answer 2

That's probably not a problem; the method is called whenever the cell needs to be painted. You don't have the luxury of controlling that.

So design the method to be very efficient and make sure it doesn't have side effects, and you will have no problem.