ReorderableTablePanel.java

/* (c) 2014 - 2016 Open Source Geospatial Foundation - all rights reserved
 * (c) 2001 - 2014 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.web.wicket;

import java.util.ArrayList;
import java.util.List;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.list.ListItem;
import org.apache.wicket.markup.html.list.ListView;
import org.apache.wicket.markup.repeater.Item;
import org.apache.wicket.markup.repeater.OddEvenItem;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.geoserver.web.data.layergroup.LayerGroupEntry;
import org.geoserver.web.wicket.GeoServerDataProvider.Property;
import org.geoserver.web.wicket.GeoServerDataProvider.PropertyPlaceholder;

import wicketdnd.DragSource;
import wicketdnd.DropTarget;
import wicketdnd.Location;
import wicketdnd.Operation;
import wicketdnd.Transfer;
import wicketdnd.theme.WebTheme;

/**
 * Base class for tables that have up/down modifiers
 * 
 * @author Andrea Aime - GeoSolutions
 * 
 * @param <T>
 */
public abstract class ReorderableTablePanel<T> extends GeoServerTablePanel<T> {

    private static final long serialVersionUID = -6732973402966999112L;

    static class ReorderableDataProvider<T> extends GeoServerDataProvider<T> {

        private static final long serialVersionUID = -5792726233183939109L;

        private List<T> items;

        private List<org.geoserver.web.wicket.GeoServerDataProvider.Property<T>> properties;

        @SuppressWarnings("unchecked")
        public ReorderableDataProvider(List<T> items, List<Property<T>> properties) {
            this.items = items;
            this.properties = new ArrayList<Property<T>>(properties);
            this.properties.add(0, (Property<T>) POSITION);
            this.properties.add(0, (Property<T>) RENDERING_ORDER);
        }

        @Override
        protected List<Property<T>> getProperties() {
            return properties;
        }

        @Override
        protected List<T> getItems() {
            return items;
        }

    }

    /**
     * Cannot declare these non static, because they would be initialized too late, and as static,
     * they cannot have the right type argument
     */
    static Property<?> POSITION = new PropertyPlaceholder<Object>("position");

    static Property<?> RENDERING_ORDER = new PropertyPlaceholder<Object>("order");

    @SuppressWarnings("serial")
    public ReorderableTablePanel(String id, List<T> items, List<Property<T>> properties) {
        super(id, new ReorderableDataProvider<T>(items, properties));
        this.setOutputMarkupId(true);
        this.add(new WebTheme());
        this.add(new DragSource(Operation.MOVE).drag("tr"));
        this.add(new DropTarget(Operation.MOVE) {

            public void onDrop(AjaxRequestTarget target, Transfer transfer, Location location) {
                if (location == null || !(location.getComponent().getDefaultModel().getObject() instanceof LayerGroupEntry)) {
                    return;
                }
                T movedItem = transfer.getData();
                T targetItem = (T) location.getComponent().getDefaultModel().getObject();
                if (movedItem.equals(targetItem)) {
                    return;
                }
                items.remove(movedItem);
                int idx = items.indexOf(targetItem);
                if(idx < (items.size() - 1)) {
                    items.add(idx, movedItem);
                } else {
                    items.add(movedItem);
                }
                target.add(ReorderableTablePanel.this);
            }
        }.dropCenter("tr"));
        
    }

    @Override
    protected void buildRowListView(GeoServerDataProvider<T> dataProvider, Item<T> item, IModel<T> itemModel) {
        // create one component per viewable property
        ListView<Property<T>> items = new ListView<Property<T>>("itemProperties", dataProvider.getVisibleProperties()) {

            private static final long serialVersionUID = -7089826211241039856L;

            @Override
            protected void populateItem(ListItem<Property<T>> item) {
                Property<T> property = item.getModelObject();

                Component component = null;
                if (property == POSITION) {
                    ParamResourceModel upTitle = new ParamResourceModel("moveToTop", this);
                    ParamResourceModel downTitle = new ParamResourceModel("moveToBottom", this);
                    component = new UpDownPanel<T>("component", (T) itemModel.getObject(),
                            dataProvider.getItems(), ReorderableTablePanel.this, upTitle, downTitle);

                } else if (property == RENDERING_ORDER) {
                    component = new Label("component", new Model<String>());
                } else {
                    component = getComponentForProperty("component", itemModel, property);
                }

                if (component == null) {
                    // show a plain label if the the subclass did not create any component
                    component = new Label("component", property.getModel(itemModel));
                } else if (!"component".equals(component.getId())) {
                    // add some checks for the id, the error message
                    // that wicket returns in case of mismatch is not
                    // that helpful
                    throw new IllegalArgumentException("getComponentForProperty asked "
                            + "to build a component " + "with id = 'component' " + "for property '"
                            + property.getName() + "', but got '" + component.getId() + "' instead");
                }
                item.add(component);
                onPopulateItem(property, item);
            }
        };
        items.setReuseItems(true);
        item.add(items);

        this.setOutputMarkupId(true);
    }

    @Override
    protected void onPopulateItem(Property<T> property, ListItem<Property<T>> item) {
        if (property == RENDERING_ORDER) {
            Label label = (Label) item.get(0);
            @SuppressWarnings("unchecked")
            OddEvenItem<T> rowContainer = (OddEvenItem<T>) item.getParent().getParent();
            label.setDefaultModel(new Model<Integer>(rowContainer.getIndex() + 1));
            item.add(new Behavior() {

                private static final long serialVersionUID = 8429550827543813897L;

                @Override
                public void onComponentTag(Component component, ComponentTag tag) {
                    tag.put("style", "width:1%");
                }
            });
        }
    };

}