burrito.client.widgets.panels.table.PageController.java Source code

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Here is the source code for burrito.client.widgets.panels.table.PageController.java

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/**
 * Copyright 2011 Henric Persson (henric.persson@gmail.com)
 * 
 * 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 burrito.client.widgets.panels.table;

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

import burrito.client.widgets.panels.table.PageController;
import burrito.client.widgets.panels.table.PageControllerHandler;
import burrito.client.widgets.panels.table.TableMessages;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.ui.Anchor;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HasHorizontalAlignment;
import com.google.gwt.user.client.ui.HasVerticalAlignment;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.PushButton;

/**
 * A page controller is a widget that separates a collection in pages. It has no
 * knowledge of the total amount of pages, only if there is at least one more to
 * fetch.
 * 
 * @author henper
 * 
 */
public class PageController extends Composite {

    private List<PageControllerHandler> handlers = new ArrayList<PageControllerHandler>();
    private int currentPageZeroIndexed = 0;
    private TableMessages messages = GWT.create(TableMessages.class);
    private Anchor currentPageLabel;
    private PushButton next;
    private PushButton previous;

    /**
     * Creates a {@link PageController} without a visible "Page:" label
     */
    public PageController() {
        this(false);
    }

    /**
     * Creates a new pagecontroller
     * 
     * @param showPageLabel
     * @param maxPagesShown
     *            If not <code>null</code> then this will be the maximum number
     *            of pages shown in the page controller.
     */
    public PageController(boolean showPageLabel) {
        HorizontalPanel wrapper = new HorizontalPanel();
        wrapper.setVerticalAlignment(HasVerticalAlignment.ALIGN_MIDDLE);
        wrapper.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_RIGHT);
        if (showPageLabel) {
            Label label = new Label(messages.page());
            label.addStyleName("k5-PageController-label");
            wrapper.add(label);
        }
        next = new PushButton(new Image(GWT.getModuleBaseURL() + "images/page-next.png?v=2"));
        previous = new PushButton(new Image(GWT.getModuleBaseURL() + "images/page-previous.png?v=2"));
        next.getUpDisabledFace().setImage(new Image(GWT.getModuleBaseURL() + "images/page-next-disabled.png?v=2"));
        previous.getUpDisabledFace()
                .setImage(new Image(GWT.getModuleBaseURL() + "images/page-previous-disabled.png?v=2"));
        next.addStyleName("k5-PageController-nextButton");
        previous.addStyleName("k5-PageController-previousButton");
        currentPageLabel = createCurrentPageAnchor();
        currentPageLabel.addStyleName("k5-PageController-link-selected");
        next.setEnabled(false);
        previous.setEnabled(false);
        next.setTitle(messages.next());
        previous.setTitle(messages.previous());
        wrapper.add(previous);
        wrapper.add(currentPageLabel);
        wrapper.add(next);
        next.addClickHandler(new ClickHandler() {

            @Override
            public void onClick(ClickEvent event) {
                for (PageControllerHandler handler : handlers) {
                    handler.loadPage(currentPageZeroIndexed + 1);
                }
            }
        });
        previous.addClickHandler(new ClickHandler() {

            @Override
            public void onClick(ClickEvent event) {
                for (PageControllerHandler handler : handlers) {
                    handler.loadPage(currentPageZeroIndexed - 1);
                }
            }
        });
        initWidget(wrapper);
        addStyleName("k5-PageController");
        setVisible(false);
    }

    private Anchor createCurrentPageAnchor() {
        Anchor a = new Anchor();
        a.addClickHandler(new ClickHandler() {

            @Override
            public void onClick(ClickEvent event) {
                for (PageControllerHandler handler : handlers) {
                    handler.loadPage(currentPageZeroIndexed);
                }
            }
        });
        a.addStyleName("k5-PageController-link");
        return a;
    }

    /**
     * Adds a listener to page events
     * 
     * @param handler
     */
    public void addPageControllerHandler(PageControllerHandler handler) {
        handlers.add(handler);
    }

    /**
     * Updates the links based on number of pages and current page
     * 
     */
    public void update(int totalPages, final int currentPageZeroIndexed) {
        if (totalPages < 2) {
            setVisible(false);
            return;
        }
        this.currentPageZeroIndexed = currentPageZeroIndexed;
        currentPageLabel.setText(String.valueOf(currentPageZeroIndexed + 1));
        setVisible(true);
        next.setEnabled(totalPages > currentPageZeroIndexed + 1);
        previous.setEnabled(currentPageZeroIndexed - 1 >= 0);
        currentPageLabel.setTitle(messages.showPage(currentPageZeroIndexed + 1));
    }

    /**
     * Gets the current page number
     * 
     * @return
     */
    public int getCurrentPage() {
        return currentPageZeroIndexed;
    }

}