vaadin-framework/server/src/com/vaadin/data/RpcDataProviderExtension.java

/*
 * Copyright 2000-2013 Vaadin Ltd.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.vaadin.data;

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

import com.vaadin.data.Container.Indexed;
import com.vaadin.server.AbstractExtension;
import com.vaadin.shared.data.DataProviderRpc;
import com.vaadin.shared.data.DataProviderState;
import com.vaadin.shared.data.DataRequestRpc;
import com.vaadin.ui.components.grid.Grid;

/**
 * Provides Vaadin server-side container data source to a
 * {@link com.vaadin.client.ui.grid.GridConnector}. This is currently
 * implemented as an Extension hardcoded to support a specific connector type.
 * This will be changed once framework support for something more flexible has
 * been implemented.
 * 
 * @since 7.2
 * @author Vaadin Ltd
 */
public class RpcDataProviderExtension extends AbstractExtension {

    private final Indexed container;

    /**
     * Creates a new data provider using the given container.
     * 
     * @param container
     *            the container to make available
     */
    public RpcDataProviderExtension(Indexed container) {
        this.container = container;

        // TODO support for reacting to events from the container added later

        registerRpc(new DataRequestRpc() {
            @Override
            public void requestRows(int firstRow, int numberOfRows) {
                pushRows(firstRow, numberOfRows);
            }
        });

        getState().containerSize = container.size();
    }

    private void pushRows(int firstRow, int numberOfRows) {
        List<?> itemIds = container.getItemIds(firstRow, numberOfRows);
        Collection<?> propertyIds = container.getContainerPropertyIds();
        List<String[]> rows = new ArrayList<String[]>(itemIds.size());
        for (Object itemId : itemIds) {
            Item item = container.getItem(itemId);
            String[] row = new String[propertyIds.size()];

            int i = 0;
            for (Object propertyId : propertyIds) {
                Object value = item.getItemProperty(propertyId).getValue();
                String stringValue = String.valueOf(value);
                row[i++] = stringValue;
            }

            rows.add(row);
        }

        getRpcProxy(DataProviderRpc.class).setRowData(firstRow, rows);
    }

    @Override
    protected DataProviderState getState() {
        return (DataProviderState) super.getState();
    }

    /**
     * Makes the data source available to the given {@link Grid} component.
     * 
     * @param component
     *            the remote data grid component to extend
     */
    public void extend(Grid component) {
        super.extend(component);
    }

}