com.google.gwt.uibinder.test.client.SimpleRenderable.java Source code

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Here is the source code for com.google.gwt.uibinder.test.client.SimpleRenderable.java

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/*
 * Copyright 2011 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.uibinder.test.client;

import com.google.gwt.dom.builder.client.DomBuilderFactory;
import com.google.gwt.dom.builder.shared.DivBuilder;
import com.google.gwt.dom.builder.shared.ElementBuilderBase;
import com.google.gwt.dom.builder.shared.ElementBuilderFactory;
import com.google.gwt.dom.builder.shared.HtmlBuilderFactory;
import com.google.gwt.dom.builder.shared.HtmlElementBuilderBase;
import com.google.gwt.dom.client.Element;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.user.client.ui.HasText;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.IsRenderable;
import com.google.gwt.user.client.ui.PotentialElement;
import com.google.gwt.user.client.ui.RenderableStamper;
import com.google.gwt.user.client.ui.Widget;

/**
 * Used by {@link IsRenderableIntegrationTest}. A simple implementation of
 * IsRenderable. Note that the actual building for both string based and dom
 * based versions happens in one place, {@link #build(ElementBuilderFactory)}.
 * <p>
 * Note also that that the widget's contents are simply re-rendered when the
 * widget's state changes, in this case in {@link #setText}. This is a bad idea
 * for large widgets, but for little leaf widgets like this one is probably just
 * fine.
 * <p>
 * It would probably be a good refactor a production super class out of this
 * once the IsRenderable interface settles down.
 * <p>
 * It's HasValue aspect is just meant for unit testing, not anything to
 * generalize.
 */
public class SimpleRenderable extends Widget implements IsRenderable, HasText, HasValue<Object> {

    private String text = "";
    private Object value;

    public SimpleRenderable() {
        setElement(PotentialElement.build(this));
    }

    @Override
    public HandlerRegistration addValueChangeHandler(ValueChangeHandler<Object> handler) {
        return addHandler(handler, ValueChangeEvent.getType());
    }

    @Override
    public void claimElement(Element element) {
        setElement(element);
    }

    @Override
    public String getText() {
        return text;
    }

    @Override
    public Object getValue() {
        return value;
    }

    @Override
    public void initializeClaimedElement() {
    }

    @Override
    public SafeHtml render(RenderableStamper stamper) {
        HtmlBuilderFactory factory = HtmlBuilderFactory.get();
        String realText = text;
        text = "[string built]" + text;
        HtmlElementBuilderBase<?> builder = (HtmlElementBuilderBase<?>) build(factory);
        text = realText;
        return stamper.stamp(builder.asSafeHtml());
    }

    @Override
    public void render(RenderableStamper stamper, SafeHtmlBuilder safeHtmlBuilder) {
        safeHtmlBuilder.append(render(stamper));
    }

    @Override
    public Element resolvePotentialElement() {
        String realText = text;
        text = "[dom built]" + text;
        ElementBuilderBase<?> builder = build(DomBuilderFactory.get());
        text = realText;
        setElement(builder.finish());
        return getElement();
    }

    @Override
    public void setText(String text) {
        this.text = text;
        updateElement();
    }

    @Override
    public void setValue(Object value) {
        setValue(value, false);
    }

    @Override
    public void setValue(Object newValue, boolean fireEvents) {
        Object oldValue = value;
        value = newValue;
        ValueChangeEvent.fireIfNotEqual(this, oldValue, newValue);
    }

    private ElementBuilderBase<?> build(ElementBuilderFactory factory) {
        DivBuilder builder = factory.createDivBuilder();
        builder.text(text).end();
        return builder;
    }

    private boolean domIsReal() {
        return !PotentialElement.isPotential(getElement());
    }

    private void updateElement() {
        if (domIsReal()) {
            String realText = text;
            text = "[updated]" + text;
            /*
             * Sleazey. If this is to get real, should split rendering into the outer
             * builder and the inner builder. Update can just call the inner builder.
             * But we'd still have to make a bunch of dom calls to tear down the old
             * guts, something like while (el.firstChild) {
             * el.removeChild(el.firstChild); }
             * 
             * Have to wonder if that actually would be any faster than rebuilding the
             * guts as string
             */
            ElementBuilderBase<?> builder = build(DomBuilderFactory.get());
            getElement().setInnerHTML(builder.finish().getInnerHTML());
            text = realText;
        }
    }
}