Java tutorial
/******************************************************************************* * Copyright (c) 2010, 2012 Tasktop Technologies * Copyright (c) 2010, 2011 SpringSource, a division of VMware * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Tasktop Technologies - initial API and implementation ******************************************************************************/ package com.tasktop.c2c.server.common.profile.web.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.client.SafeHtmlTemplates.Template; import com.google.gwt.safehtml.shared.SafeHtml; import com.google.gwt.safehtml.shared.SafeHtmlBuilder; import com.google.gwt.text.shared.SafeHtmlRenderer; import com.google.gwt.text.shared.SimpleSafeHtmlRenderer; public class TextAreaInputCell extends AbstractInputCell<String, TextAreaInputCell.ViewData> { interface Template extends SafeHtmlTemplates { @Template("<textarea tabindex=\"-2\">{0}</textarea>") SafeHtml input(String value); } /** * The {@code ViewData} for this cell. */ public static class ViewData { /** * The last value that was updated. */ private String lastValue; /** * The current value. */ private String curValue; /** * Construct a ViewData instance containing a given value. * * @param value * a String value */ public ViewData(String value) { this.lastValue = value; this.curValue = value; } /** * Return true if the last and current values of this ViewData object are equal to those of the other object. */ @Override public boolean equals(Object other) { if (!(other instanceof ViewData)) { return false; } ViewData vd = (ViewData) other; return equalsOrNull(lastValue, vd.lastValue) && equalsOrNull(curValue, vd.curValue); } /** * Return the current value of the input element. * * @return the current value String * @see #setCurrentValue(String) */ public String getCurrentValue() { return curValue; } /** * Return the last value sent to the {@link ValueUpdater}. * * @return the last value String * @see #setLastValue(String) */ public String getLastValue() { return lastValue; } /** * Return a hash code based on the last and current values. */ @Override public int hashCode() { return (lastValue + "_*!@HASH_SEPARATOR@!*_" + curValue).hashCode(); } /** * Set the current value. * * @param curValue * the current value * @see #getCurrentValue() */ protected void setCurrentValue(String curValue) { this.curValue = curValue; } /** * Set the last value. * * @param lastValue * the last value * @see #getLastValue() */ protected void setLastValue(String lastValue) { this.lastValue = lastValue; } private boolean equalsOrNull(Object a, Object b) { return (a != null) ? a.equals(b) : ((b == null) ? true : false); } } private static Template template; private final SafeHtmlRenderer<String> renderer; /** * Constructs a TextAreaInputCell that renders its text without HTML markup. */ public TextAreaInputCell() { this(SimpleSafeHtmlRenderer.getInstance()); } /** * Constructs a TextAreaInputCell that renders its text using the given {@link SafeHtmlRenderer}. * * @param renderer * a non-null SafeHtmlRenderer */ public TextAreaInputCell(SafeHtmlRenderer<String> renderer) { super("change", "keyup"); if (template == null) { template = GWT.create(Template.class); } if (renderer == null) { throw new IllegalArgumentException("renderer == null"); } this.renderer = renderer; } @Override public void onBrowserEvent(Context context, Element parent, String value, NativeEvent event, 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(); if ("change".equals(eventType)) { finishEditing(parent, value, context.getKey(), valueUpdater); } else if ("keyup".equals(eventType)) { // Record keys as they are typed. ViewData vd = getViewData(context.getKey()); if (vd == null) { vd = new ViewData(value); setViewData(context.getKey(), vd); } vd.setCurrentValue(input.getValue()); } } @Override public void render(Context context, String value, SafeHtmlBuilder sb) { // Get the view data. ViewData viewData = getViewData(context.getKey()); if (viewData != null && viewData.getCurrentValue().equals(value)) { clearViewData(context.getKey()); viewData = null; } String s = (viewData != null) ? viewData.getCurrentValue() : value; if (s != null) { SafeHtml html = renderer.render(s); // Note: template will not treat SafeHtml specially sb.append(template.input(html.asString())); } else { sb.appendHtmlConstant("<textarea tabindex=\"-1\"></textarea>"); } } @Override protected void finishEditing(Element parent, String value, Object key, 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(Element parent) { return super.getInputElement(parent).<InputElement>cast(); } }