CheckboxCellImpl.java

/*
 * Copyright 2015 JBoss, by Red Hat, 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 org.uberfire.ext.widgets.table.client;

import com.google.gwt.cell.client.AbstractEditableCell;
import com.google.gwt.cell.client.Cell;
import com.google.gwt.cell.client.ValueUpdater;
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.event.dom.client.KeyCodes;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;

/**
 * A {@link Cell} used to render a checkbox. The value of the checkbox may be
 * toggled using the ENTER key as well as via mouse click.
 */
public class CheckboxCellImpl extends AbstractEditableCell<Boolean, Boolean> {

    /**
     * An html string representation of a checked input box.
     */
    private static final SafeHtml INPUT_CHECKED = SafeHtmlUtils.fromSafeConstant("<input type=\"checkbox\" tabindex=\"-1\" checked/>");

    /**
     * An html string representation of an unchecked input box.
     */
    private static final SafeHtml INPUT_UNCHECKED = SafeHtmlUtils.fromSafeConstant("<input type=\"checkbox\" tabindex=\"-1\"/>");

    /**
     * An html string representation of a read-only checked input box.
     */
    private static final SafeHtml READ_ONLY_INPUT_CHECKED = SafeHtmlUtils.fromSafeConstant("<input type=\"checkbox\" tabindex=\"-1\" checked disabled=\"disabled\"/>");

    /**
     * An html string representation of a read-only unchecked input box.
     */
    private static final SafeHtml READ_ONLY_INPUT_UNCHECKED = SafeHtmlUtils.fromSafeConstant("<input type=\"checkbox\" tabindex=\"-1\" disabled=\"disabled\"/>");

    protected boolean isReadOnly;

    /**
     * Construct a new {@link CheckboxCellImpl}
     */
    public CheckboxCellImpl(boolean isReadOnly) {
        super("click",
              "keydown");
        this.isReadOnly = isReadOnly;
    }

    CheckboxCellImpl(String... consumedEvents) {
        super(consumedEvents);
    }

    @Override
    public boolean isEditing(Context context,
                             Element parent,
                             Boolean value) {
        // A checkbox is never in "edit mode". There is no intermediate state
        // between checked and unchecked.
        return false;
    }

    @Override
    public void onBrowserEvent(Context context,
                               Element parent,
                               Boolean value,
                               NativeEvent event,
                               ValueUpdater<Boolean> valueUpdater) {

        //If read-only ignore editing events
        if (isReadOnly) {
            return;
        }

        String type = event.getType();

        boolean enterPressed = "keydown".equals(type) && event.getKeyCode() == KeyCodes.KEY_ENTER;
        if ("click".equals(type) || enterPressed) {
            InputElement input = parent.getFirstChild().cast();
            Boolean isChecked = input.isChecked();

            /*
             * Toggle the value if the enter key was pressed and the cell
             * handles selection or doesn't depend on selection. If the cell
             * depends on selection but doesn't handle selection, then ignore
             * the enter key and let the SelectionEventManager determine which
             * keys will trigger a change.
             */
            if (enterPressed) {
                isChecked = !isChecked;
                input.setChecked(isChecked);
            }

            /*
             * Save the new value. However, if the cell depends on the
             * selection, then do not save the value because we can get into an
             * inconsistent state.
             */
            if (value != isChecked) {
                setViewData(context.getKey(),
                            isChecked);
            }

            if (valueUpdater != null) {
                valueUpdater.update(isChecked);
            }
        }
    }

    @Override
    public void render(Context context,
                       Boolean value,
                       SafeHtmlBuilder sb) {
        // Get the view data.
        Object key = context.getKey();
        Boolean viewData = getViewData(key);
        if (viewData != null && viewData.equals(value)) {
            clearViewData(key);
            viewData = null;
        }

        if (value != null && ((viewData != null) ? viewData : value)) {
            if (isReadOnly) {
                sb.append(READ_ONLY_INPUT_CHECKED);
            } else {
                sb.append(INPUT_CHECKED);
            }
        } else {
            if (isReadOnly) {
                sb.append(READ_ONLY_INPUT_UNCHECKED);
            } else {
                sb.append(INPUT_UNCHECKED);
            }
        }
    }
}