Synnefo » Pithos

/*

 * Copyright 2010 Google Inc.

 *

 * 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 gr.grnet.pithos.web.client;

import com.google.gwt.cell.client.Cell.Context;

import com.google.gwt.cell.client.ClickableTextCell;

import com.google.gwt.core.client.GWT;

import com.google.gwt.resources.client.ClientBundle;

import com.google.gwt.resources.client.ImageResource;

import com.google.gwt.safehtml.client.SafeHtmlTemplates;

import com.google.gwt.safehtml.shared.SafeHtml;

import com.google.gwt.safehtml.shared.SafeHtmlBuilder;

import com.google.gwt.safehtml.shared.SafeHtmlUtils;

import com.google.gwt.user.cellview.client.Header;

import com.google.gwt.user.client.ui.AbstractImagePrototype;

/**

 * A {@link Header} subclass that maintains sorting state and displays an icon

 * to indicate the sort direction.

 */

public class SortableHeader extends Header<String> {

  interface Template extends SafeHtmlTemplates {

    @Template("<div style=\"position:relative;cursor:hand;cursor:pointer;"

        + "padding-right:{0}px;\">{1}<div>{2}</div></div>")

    SafeHtml sorted(int imageWidth, SafeHtml arrow, String text);

    @Template("<div style=\"position:relative;cursor:hand;cursor:pointer;"

        + "padding-right:{0}px;\"><div style=\"position:absolute;display:none;"

        + "\"></div><div>{1}</div></div>")

    SafeHtml unsorted(int imageWidth, String text);

  }

  private static Template template;

  /**

   * Image resources.

   */

  public static interface Resources extends ClientBundle {

    ImageResource downArrow();

    ImageResource upArrow();

  }

  private static final Resources RESOURCES = GWT.create(Resources.class);

  private static final int IMAGE_WIDTH = 16;

  private static final SafeHtml DOWN_ARROW = makeImage(RESOURCES.downArrow());

  private static final SafeHtml UP_ARROW = makeImage(RESOURCES.upArrow());

  private static SafeHtml makeImage(ImageResource resource) {

    AbstractImagePrototype proto = AbstractImagePrototype.create(resource);

    String html = proto.getHTML().replace("style='",

        "style='position:absolute;right:0px;top:0px;");

    return SafeHtmlUtils.fromTrustedString(html);

  }

  private boolean reverseSort = false;

  private boolean sorted = false;

  private String text;

  SortableHeader(String text) {

    super(new ClickableTextCell());

    if (template == null) {

      template = GWT.create(Template.class);

    }

    this.text = text;

  }

  public boolean getReverseSort() {

    return reverseSort;

  }

  @Override

  public String getValue() {

    return text;

  }

  @Override

  public void render(Context context, SafeHtmlBuilder sb) {

    if (sorted) {

      sb.append(template.sorted(IMAGE_WIDTH, reverseSort ? DOWN_ARROW : UP_ARROW, text));

    } else {

      sb.append(template.unsorted(IMAGE_WIDTH, text));

    }

  }

  public void setReverseSort(boolean reverseSort) {

    this.reverseSort = reverseSort;

  }

  public void setSorted(boolean sorted) {

    this.sorted = sorted;

  }

  public void toggleReverseSort() {

    this.reverseSort = !this.reverseSort;

  }

}