InlineHyperlinkPushState.java

/*
 * Copyright 2012 Johannes Barop
 * 
 * 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 de.barop.gwt.client.ui;

import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.History;
import com.google.gwt.user.client.ui.InlineHyperlink;

import de.barop.gwt.client.CodeServerParameterHelper;

/**
 * Widget that is an internal hyperlink and supports HTML5 pushState.
 * 
 * <p>
 * It extends GWT's original {@link InlineHyperlink} and moves the history token from the hash to
 * the path.
 * <p>
 * 
 * <p>
 * This has the advantage that no-pushState browsers see the correct nice link while still using a
 * {@link History} implementation which does not cause reloads.
 * <p>
 * 
 * @author <a href="mailto:jb@barop.de">Johannes Barop</a>
 * 
 */
public class InlineHyperlinkPushState extends InlineHyperlink {

  private String targetHistoryToken;

  /**
   * Calls {@link InlineHyperlink#InlineHyperlink(String, String)}.
   */
  public InlineHyperlinkPushState(final String text, final String targetHistoryToken) {
    super(text, targetHistoryToken);
  }

  /**
   * No arg constructor, calls {@link InlineHyperlink#InlineHyperlink()}.  
   */
  public InlineHyperlinkPushState() {
  }

  @Override
  public void setTargetHistoryToken(final String targetHistoryToken) {
    assert targetHistoryToken != null : "New history item cannot be null!";

    this.targetHistoryToken = targetHistoryToken;

    String href = (targetHistoryToken.startsWith("/")) ? targetHistoryToken : "/" + targetHistoryToken;
    DOM.setElementProperty(getElement(), "href", CodeServerParameterHelper.append(href));
  }

  @Override
  public String getTargetHistoryToken() {
    return targetHistoryToken;
  }

}