CollectionPanel.java

package pt.ist.vaadinframework.ui;

import java.lang.reflect.Method;

import com.vaadin.data.Buffered;
import com.vaadin.data.Container;
import com.vaadin.ui.Alignment;
import com.vaadin.ui.Button;
import com.vaadin.ui.Component;
import com.vaadin.ui.CustomComponent;
import com.vaadin.ui.GridLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.themes.BaseTheme;

/**
 * Creates a panel that view and manage a collection of items.
 * 
 * @author David Martinho (davidmartinho@ist.utl.pt)
 */
public abstract class CollectionPanel extends CustomComponent implements Container.Viewer, Container.Editor,
        Container.ItemSetChangeListener, Container.ItemSetChangeNotifier {

    private static final long serialVersionUID = -8342680039386201881L;

    private static final String CSS_COLLECTION_PANEL = "v-collectionpanel";
    private static final String CSS_COLLECTION_LABEL = "v-collectionpanel-label";
    private static final String CSS_COLLECTION_ADD_BUTTON = "v-collectionpanel-add-button";
    private static final String CSS_COLLECTION_REMOVE_BUTTON = "v-collectionpanel-remove-button";
    private static final String CSS_COLLECTION_CONTAINER = "v-collectionpanel-container";

    private GridLayout container;

    private boolean isRemovable = false;

    private Button addButton;
    private Button removeButton;
    private Label nameLabel;
    private Panel itemLayoutContainer;

    private Container itemContainer;

    public CollectionPanel(boolean isRemovable) {
        this.isRemovable = isRemovable;
        bindUi();
    }

    private void bindUi() {
        container = new GridLayout(3, 3);
        container.addStyleName(CSS_COLLECTION_PANEL);
        container.setSizeFull();
        bindAddButton();
        bindRemoveButton();
        bindCollectionNameLabel();
        bindContainer();
        setCompositionRoot(container);
    }

    private void bindAddButton() {
        addButton = new Button("+");
        addButton.addStyleName(BaseTheme.BUTTON_LINK);
        addButton.addStyleName(CSS_COLLECTION_ADD_BUTTON);
        addButton.setSizeUndefined();
        container.addComponent(addButton, 0, 1, 0, 1);
        container.setComponentAlignment(addButton, Alignment.TOP_RIGHT);
    }

    private void bindRemoveButton() {
        if (isRemovable) {
            removeButton = new Button("X");
            removeButton.addStyleName(BaseTheme.BUTTON_LINK);
            removeButton.addStyleName(CSS_COLLECTION_REMOVE_BUTTON);
            removeButton.setSizeUndefined();
            container.addComponent(removeButton, 2, 0, 2, 0);
        }
    }

    private void bindCollectionNameLabel() {
        nameLabel = new Label();
        nameLabel.addStyleName(CSS_COLLECTION_LABEL);
        nameLabel.setSizeUndefined();
        container.addComponent(nameLabel, 1, 0, 1, 0);
        container.setComponentAlignment(nameLabel, Alignment.BOTTOM_LEFT);
    }

    private void bindContainer() {
        itemLayoutContainer = new Panel();
        VerticalLayout wrapper = new VerticalLayout();
        wrapper.setMargin(true);
        wrapper.setSpacing(true);
        itemLayoutContainer.setContent(wrapper);
        itemLayoutContainer.addStyleName(CSS_COLLECTION_CONTAINER);
        container.addComponent(itemLayoutContainer, 1, 1, 2, 2);
        container.setColumnExpandRatio(1, 1f);
    }

    public Label getNameLabel() {
        return nameLabel;
    }

    public Button getAddButton() {
        return addButton;
    }

    public Button getRemoveButton() {
        return removeButton;
    }

    public Panel getItemLayoutContainer() {
        return itemLayoutContainer;
    }

    public void setWriteThrough(boolean state) {
        if (itemContainer != null) {
            ((Buffered) itemContainer).setWriteThrough(state);
        }
    }

    @Override
    public void setContainerDataSource(Container newDataSource) {
        if (itemContainer != newDataSource) {
            if (itemContainer != null) {
                if (itemContainer instanceof Container.ItemSetChangeNotifier) {
                    ((Container.ItemSetChangeNotifier) itemContainer).removeListener(this);
                }
            }

            // Assigns new data source
            itemContainer = newDataSource;
            refreshComponents(itemContainer);

            // Adds listeners
            if (itemContainer != null) {
                if (itemContainer instanceof Container.ItemSetChangeNotifier) {
                    ((Container.ItemSetChangeNotifier) itemContainer).addListener(this);
                }
            }
        }
    }

    public void refreshComponents() {
        refreshComponents(getContainerDataSource());
    }

    protected abstract void refreshComponents(Container itemContainer);

    @Override
    public Container getContainerDataSource() {
        return itemContainer;
    }

    public void setNameLabel(String newValue) {
        this.nameLabel.setValue(newValue);
    }

    @Override
    public void containerItemSetChange(com.vaadin.data.Container.ItemSetChangeEvent event) {
        fireItemSetChangeEvent();
    }

    private void fireItemSetChangeEvent() {
        fireEvent(new CollectionPanel.ItemSetChangeEvent(this));
        requestRepaint();
    }

    public class ItemSetChangeEvent extends Component.Event implements Container.ItemSetChangeEvent {

        private static final long serialVersionUID = -6054196818392240334L;

        public ItemSetChangeEvent(CollectionPanel source) {
            super(source);
        }

        @Override
        public Container getContainer() {
            return (Container) getSource();
        }
    }

    @Override
    public void addListener(Container.ItemSetChangeListener listener) {
        addListener(CollectionPanel.ItemSetChangeEvent.class, listener, ITEM_SET_CHANGE_METHOD);
    }

    @Override
    public void removeListener(Container.ItemSetChangeListener listener) {
        removeListener(CollectionPanel.ItemSetChangeEvent.class, listener, ITEM_SET_CHANGE_METHOD);
    }

    private static final Method ITEM_SET_CHANGE_METHOD;

    static {
        try {
            ITEM_SET_CHANGE_METHOD =
                    Container.ItemSetChangeListener.class.getDeclaredMethod("containerItemSetChange",
                            new Class[] { Container.ItemSetChangeEvent.class });
        } catch (final java.lang.NoSuchMethodException e) {
            // This should never happen
            throw new java.lang.RuntimeException("Internal error finding methods in CollectionPanel");
        }
    }
}