com.google.gwt.user.client.ui.impl.FocusImpl.java Source code

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Here is the source code for com.google.gwt.user.client.ui.impl.FocusImpl.java

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/*
 * Copyright 2006 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 com.google.gwt.user.client.ui.impl;

import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;

/**
 * Implementation interface for creating and manipulating focusable elements
 * that aren't naturally focusable in all browsers, such as DIVs.
 */
public class FocusImpl {
    private static FocusImpl implPanel = GWT.create(FocusImpl.class);

    /**
     * This instance may not be a {@link FocusImplStandard}, because that
     * special case is only needed for things that aren't naturally focusable on
     * some browsers, such as DIVs. This exact class works for truly focusable
     * widgets on those browsers.
     * 
     * The compiler will optimize out the conditional.
     */
    private static FocusImpl implWidget = (implPanel instanceof FocusImplStandard) ? new FocusImpl() : implPanel;

    /**
     * Returns the focus implementation class for creating and manipulating
     * focusable elements that aren't naturally focusable in all browsers, such
     * as DIVs.
     */
    public static FocusImpl getFocusImplForPanel() {
        return implPanel;
    }

    /**
     * Returns the focus implementation class for manipulating focusable
     * elements that are naturally focusable in all browsers, such as text
     * boxes.
     */
    public static FocusImpl getFocusImplForWidget() {
        return implWidget;
    }

    /**
     * Not externally instantiable or extensible.
     */
    FocusImpl() {
    }

    public void blur(Element elem) {
        elem.blur();
    }

    public Element createFocusable() {
        Element e = Document.get().createDivElement().cast();
        e.setTabIndex(0);
        return e;
    }

    public void focus(Element elem) {
        elem.focus();
    }

    public int getTabIndex(Element elem) {
        return elem.getTabIndex();
    }

    public native void setAccessKey(Element elem, char key) /*-{
                                                            var remote=elem.@com.google.gwt.dom.client.Element::typedRemote()();
                                                            remote.accessKey = String.fromCharCode(key);
                                                            }-*/;

    public void setTabIndex(Element elem, int index) {
        elem.setTabIndex(index);
    }
}