org.mklab.taskit.client.ui.cell.SelectCell.java Source code

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Here is the source code for org.mklab.taskit.client.ui.cell.SelectCell.java

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/*
 * 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.mklab.taskit.client.ui.cell;

import java.util.List;

import com.google.gwt.cell.client.AbstractInputCell;
import com.google.gwt.cell.client.ValueUpdater;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.dom.client.Node;
import com.google.gwt.dom.client.SelectElement;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;

/**
 * ??????
 * <p>
 * ?????????????????????????????
 * 
 * @author ishikura
 * @param <E> ?
 */
public class SelectCell<E> extends AbstractInputCell<E, E> {

    private List<E> options;
    private boolean editable = true;
    private Renderer<E> renderer;
    private Comparator<E> comparator;

    /**
     * {@link SelectCell}???
     * 
     * @param options ????
     */
    public SelectCell(List<E> options) {
        this(options, new Renderer<E>() {

            @Override
            public String render(@SuppressWarnings("unused") int index, E value) {
                return String.valueOf(value);
            }
        });
    }

    /**
     * {@link SelectCell}???
     * 
     * @param options ????
     * @param renderer ???????
     */
    public SelectCell(List<E> options, Renderer<E> renderer) {
        this(options, renderer, new Comparator<E>() {

            @Override
            public boolean equals(E e1, E e2) {
                if (e1 == null) {
                    if (e2 == null) {
                        return true;
                    }
                    return false;
                }
                return e1.equals(e2);
            }
        });
    }

    /**
     * {@link SelectCell}???
     * 
     * @param options ????
     * @param renderer ???????
     * @param comparator ???
     */
    public SelectCell(List<E> options, Renderer<E> renderer, Comparator<E> comparator) {
        super("change"); //$NON-NLS-1$
        if (options == null)
            throw new NullPointerException();
        if (renderer == null)
            throw new NullPointerException();
        if (comparator == null)
            throw new NullPointerException();
        this.options = options;
        this.renderer = renderer;
        this.comparator = comparator;
    }

    /**
     * editable???
     * 
     * @param editable editable
     */
    public void setEditable(boolean editable) {
        this.editable = editable;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onBrowserEvent(com.google.gwt.cell.client.Cell.Context context, Element parent, E value,
            NativeEvent event, ValueUpdater<E> valueUpdater) {
        if (this.editable == false)
            return;

        if ("change".equals(event.getType()) == false) //$NON-NLS-1$
            return;

        final SelectElement select = getSelectElement(parent);
        final int selectedIndex = select.getSelectedIndex();
        if (selectedIndex < 0)
            return;

        final E selectedValue = this.options.get(selectedIndex);
        finishEditing(parent, value, context.getKey(), valueUpdater);
        if (valueUpdater != null) {
            valueUpdater.update(selectedValue);
        }
    }

    private static SelectElement getSelectElement(Element parent) {
        Node child = parent;
        do {
            if (child.getNodeName().toLowerCase().equals("select")) //$NON-NLS-1$
                return child.cast();
        } while ((child = child.getFirstChild()) != null);
        return null;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("nls")
    @Override
    public void render(@SuppressWarnings("unused") com.google.gwt.cell.client.Cell.Context context, E value,
            SafeHtmlBuilder sb) {
        if (this.editable) {
            sb.appendHtmlConstant("<select>");
        } else {
            int index = 0;
            for (E option : this.options) {
                final boolean selected = this.comparator.equals(option, value);
                if (selected) {
                    final String escapedOption = SafeHtmlUtils.htmlEscape(this.renderer.render(index++, option));
                    sb.appendEscaped(escapedOption);
                }
            }
            return;
        }

        int index = 0;
        for (E option : this.options) {
            final boolean selected = this.comparator.equals(option, value);
            final String escapedOption = SafeHtmlUtils.htmlEscape(this.renderer.render(index++, option));
            sb.appendHtmlConstant("<option value='" + escapedOption + "'" + (selected ? " selected" : "") + ">"
                    + escapedOption + "</option>");
        }
        sb.appendHtmlConstant("</select>");
    }

    /**
     * ?????????
     * 
     * @author ishikura
     * @param <E> ?
     */
    public static interface Renderer<E> {

        /**
         * ????
         * 
         * @param index ?
         * @param value 
         * @return 
         */
        String render(int index, E value);

    }

    /**
     * ????
     * 
     * @author ishikura
     * @param <E> ?
     */
    public static interface Comparator<E> {

        /**
         * ???????????
         * 
         * @param e1 
         * @param e2 
         * @return ?????????
         */
        boolean equals(E e1, E e2);
    }

}