com.goodow.web.reader.client.TextAreaCell.java Source code

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Here is the source code for com.goodow.web.reader.client.TextAreaCell.java

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/*
 * Copyright 2012 Goodow.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 com.goodow.web.reader.client;

import com.google.gwt.cell.client.AbstractInputCell;
import com.google.gwt.cell.client.ValueUpdater;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.InputElement;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.safehtml.client.SafeHtmlTemplates;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;

public class TextAreaCell extends AbstractInputCell<String, TextAreaCell.ViewData> {

    public static class ViewData {

        private String lastValue;

        private String curValue;

        public ViewData(final String value) {
            this.lastValue = value;
            this.curValue = value;
        }

        @Override
        public boolean equals(final Object other) {
            if (!(other instanceof ViewData)) {
                return false;
            }
            ViewData vd = (ViewData) other;
            return equalsOrNull(lastValue, vd.lastValue) && equalsOrNull(curValue, vd.curValue);
        }

        public String getCurrentValue() {
            return curValue;
        }

        public String getLastValue() {
            return lastValue;
        }

        @Override
        public int hashCode() {
            return (lastValue + "_*!@HASH_SEPARATOR@!*_" + curValue).hashCode();
        }

        protected void setCurrentValue(final String curValue) {
            this.curValue = curValue;
        }

        protected void setLastValue(final String lastValue) {
            this.lastValue = lastValue;
        }

        private boolean equalsOrNull(final Object a, final Object b) {
            return (a != null) ? a.equals(b) : ((b == null) ? true : false);
        }
    }

    interface Template extends SafeHtmlTemplates {
        @Template("<textarea rows=\"3\" dir style=\"resize: none;margin: 2px; width: 130px;height: 50px;\">{0}</textarea>")
        SafeHtml input(String value);
    }

    private static Template template;

    public TextAreaCell() {
        super("change", "keyup");
        if (template == null) {
            template = GWT.create(Template.class);
        }
    }

    @Override
    public void onBrowserEvent(final Context context, final Element parent, final String value,
            final NativeEvent event, final ValueUpdater<String> valueUpdater) {
        super.onBrowserEvent(context, parent, value, event, valueUpdater);

        // Ignore events that don't target the input.
        InputElement input = getInputElement(parent);
        Element target = event.getEventTarget().cast();
        if (!input.isOrHasChild(target)) {
            return;
        }

        String eventType = event.getType();
        Object key = context.getKey();
        if ("change".equals(eventType)) {
            finishEditing(parent, value, key, valueUpdater);
        } else if ("keyup".equals(eventType)) {
            // Record keys as they are typed.
            ViewData vd = getViewData(key);
            if (vd == null) {
                vd = new ViewData(value);
                setViewData(key, vd);
            }
            vd.setCurrentValue(input.getValue());
        }
    }

    @Override
    public void render(final com.google.gwt.cell.client.Cell.Context context, final String value,
            final SafeHtmlBuilder sb) {
        Object key = context.getKey();
        ViewData viewData = getViewData(key);
        if (viewData != null && viewData.getCurrentValue().equals(value)) {
            clearViewData(key);
            viewData = null;
        }

        String s = (viewData != null) ? viewData.getCurrentValue() : value;
        if (s != null) {
            sb.append(template.input(s));
        } else {
            sb.appendHtmlConstant(
                    "<textarea  rows=\"3\" dir style=\"resize: none;margin: 2px; width: 130px;height: 50px;\"></textarea>");
        }
    }

    @Override
    protected void finishEditing(final Element parent, final String value, final Object key,
            final ValueUpdater<String> valueUpdater) {
        String newValue = getInputElement(parent).getValue();

        // Get the view data.
        ViewData vd = getViewData(key);
        if (vd == null) {
            vd = new ViewData(value);
            setViewData(key, vd);
        }
        vd.setCurrentValue(newValue);

        // Fire the value updater if the value has changed.
        if (valueUpdater != null && !vd.getCurrentValue().equals(vd.getLastValue())) {
            vd.setLastValue(newValue);
            valueUpdater.update(newValue);
        }

        // Blur the element.
        super.finishEditing(parent, newValue, key, valueUpdater);
    }

    @Override
    protected InputElement getInputElement(final Element parent) {
        return super.getInputElement(parent).<InputElement>cast();
    }

}