stroom.cell.expander.client.ExpanderCell.java Source code

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Here is the source code for stroom.cell.expander.client.ExpanderCell.java

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/*
 * Copyright 2016 Crown Copyright
 *
 * 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 stroom.cell.expander.client;

import stroom.util.shared.Expander;
import com.google.gwt.cell.client.AbstractCell;
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.EventTarget;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.resources.client.ClientBundle;
import com.google.gwt.resources.client.CssResource;
import com.google.gwt.resources.client.ImageResource;
import com.google.gwt.safecss.shared.SafeStyles;
import com.google.gwt.safecss.shared.SafeStylesUtils;
import com.google.gwt.safehtml.client.SafeHtmlTemplates;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.user.client.ui.AbstractImagePrototype;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class ExpanderCell extends AbstractCell<Expander> {
    interface Resources extends ClientBundle {
        ImageResource open();

        ImageResource closed();

        ImageResource leaf();

        @Source("expander.css")
        Style style();
    }

    interface Style extends CssResource {
        String active();
    }

    interface Template extends SafeHtmlTemplates {
        @Template("<div class=\"{0}\" style=\"{1}\">{2}</div>")
        SafeHtml outerDiv(String className, SafeStyles style, SafeHtml icon);
    }

    private static final Set<String> ENABLED_EVENTS = new HashSet<>(Arrays.asList("click", "keydown"));

    private static volatile Resources resources;
    private static volatile Template template;

    public ExpanderCell() {
        super(ENABLED_EVENTS);
        if (resources == null) {
            synchronized (ExpanderCell.class) {
                if (resources == null) {
                    resources = GWT.create(Resources.class);
                    resources.style().ensureInjected();
                    template = GWT.create(Template.class);
                }
            }
        }
    }

    @Override
    public void onBrowserEvent(final Context context, final Element parent, final Expander value,
            final NativeEvent event, final ValueUpdater<Expander> valueUpdater) {
        super.onBrowserEvent(context, parent, value, event, valueUpdater);
        if ("click".equals(event.getType())) {
            final EventTarget eventTarget = event.getEventTarget();
            if (!Element.is(eventTarget)) {
                return;
            }
            if (parent.getFirstChildElement().isOrHasChild(Element.as(eventTarget))) {
                // Ignore clicks that occur outside of the main element.
                onEnterKeyDown(context, parent, value, event, valueUpdater);
            }
        }
    }

    @Override
    protected void onEnterKeyDown(final Context context, final Element parent, final Expander value,
            final NativeEvent event, final ValueUpdater<Expander> valueUpdater) {
        if (valueUpdater != null && value != null && !value.isLeaf()) {
            valueUpdater.update(value);
        }
    }

    @Override
    public void render(final Context context, final Expander value, final SafeHtmlBuilder sb) {
        if (value != null) {
            final int depth = value.getDepth();
            final int padding = depth * 10;
            final SafeStyles style = SafeStylesUtils.fromTrustedString("padding-left:" + padding + "px;");
            String className = "";
            SafeHtml icon = null;

            if (value.isLeaf()) {
                icon = getImageHtml(resources.leaf());
            } else if (value.isExpanded()) {
                icon = getImageHtml(resources.open());
                className = resources.style().active();
            } else {
                icon = getImageHtml(resources.closed());
                className = resources.style().active();
            }

            sb.append(template.outerDiv(className, style, icon));

        } else {
            sb.append(SafeHtmlUtils.fromSafeConstant("<br/>"));
        }
    }

    private SafeHtml getImageHtml(final ImageResource res) {
        // Get the HTML for the image.
        final AbstractImagePrototype proto = AbstractImagePrototype.create(res);
        final SafeHtml image = SafeHtmlUtils.fromTrustedString(proto.getHTML());
        return image;
    }
}