001    /*
002     *  Copyright 2012 GWT-Bootstrap
003     *
004     *  Licensed under the Apache License, Version 2.0 (the "License");
005     *  you may not use this file except in compliance with the License.
006     *  You may obtain a copy of the License at
007     *
008     *      http://www.apache.org/licenses/LICENSE-2.0
009     *
010     *  Unless required by applicable law or agreed to in writing, software
011     *  distributed under the License is distributed on an "AS IS" BASIS,
012     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     *  See the License for the specific language governing permissions and
014     *  limitations under the License.
015     */
016    package com.github.gwtbootstrap.client.ui.base;
017    
018    import com.github.gwtbootstrap.client.ui.constants.Constants;
019    import com.google.gwt.user.client.Element;
020    
021    
022    /**
023     * The helper class for {@link HasPlaceholder} interface.
024     * 
025     * @since 2.0.4.0
026     * @author ohashi keisuke
027     *
028     */
029    public class PlaceholderHelper {
030    
031            //TODO 2012/05/04 ohashi keisuke. Support for non HTML5 Browser.
032            //I designed this class as non static class.
033            //Maybe we can use deffered binding for non HTML5 Browser support.
034            
035            /**
036             * Set a placeholder attribute (HTML5) to the element.
037             * 
038             * @param element the element be set 
039             * @param placeholder
040             *            the String to show. Use a empty string or null to remove the attribute.
041             */
042            public void setPlaceholer(Element element , String placeholder) {
043                    if (placeholder == null || placeholder.trim().isEmpty()) {
044                            element.removeAttribute(Constants.PLACEHOLDER);
045                            return;
046                    }
047                    element.setAttribute(Constants.PLACEHOLDER, placeholder);
048            }
049            
050            /**
051             * Get a placeholder attribute (HTML5) from the element.
052             * <p>
053             * If the element don't have placeholder attribute,This return empty string.
054             * </p>
055             * @param element the element
056             * @return placeholder attribute.
057             */
058            public String getPlaceholder(Element element) {
059                    return element.hasAttribute(Constants.PLACEHOLDER) 
060                                    ? element.getAttribute(Constants.PLACEHOLDER)
061                                    : "";
062            }
063    }