com.google.gwt.cell.client.AbstractEditableCell.java Source code

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Here is the source code for com.google.gwt.cell.client.AbstractEditableCell.java

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/*
 * Copyright 2010 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.cell.client;

import com.google.gwt.cell.client.Cell.Context;
import com.google.gwt.dom.client.Element;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * A default implementation of the {@link Cell} interface used for editable
 * cells that need to save view data state for specific values.
 *
 * <p>
 * <h3>Example</h3>
 * {@example com.google.gwt.examples.cell.EditableCellExample}
 * </p>
 *
 * @param <C> the type that this Cell represents
 * @param <V> the data type of the view data state
 */
public abstract class AbstractEditableCell<C, V> extends AbstractCell<C> {

    /**
     * The map of value keys to the associated view data.
     */
    private final Map<Object, V> viewDataMap = new HashMap<Object, V>();

    /**
     * Construct a new {@link AbstractEditableCell} with the specified consumed
     * events.
     *
     * @param consumedEvents the events that this cell consumes
     */
    public AbstractEditableCell(String... consumedEvents) {
        super(consumedEvents);
    }

    /**
     * Construct a new {@link AbstractEditableCell} with the specified consumed
     * events.
     *
     * @param consumedEvents the events that this cell consumes
     */
    public AbstractEditableCell(Set<String> consumedEvents) {
        super(consumedEvents);
    }

    /**
     * Clear the view data associated with the specified key.
     *
     * @param key the key identifying the row value
     */
    public void clearViewData(Object key) {
        if (key != null) {
            viewDataMap.remove(key);
        }
    }

    /**
     * Get the view data associated with the specified key.
     *
     * @param key the key identifying the row object
     * @return the view data, or null if none has been set
     * @see #setViewData(Object, Object)
     */
    public V getViewData(Object key) {
        return (key == null) ? null : viewDataMap.get(key);
    }

    /**
     * Returns true if the cell is currently editing the data identified by the
     * given element and key. While a cell is editing, widgets containing the cell
     * may choose to pass keystrokes directly to the cell rather than using them
     * for navigation purposes.
     * 
     * @param context the {@link Context} of the cell
     * @param parent the parent Element
     * @param value the value associated with the cell
     * @return true if the cell is in edit mode
     */
    @Override
    public abstract boolean isEditing(Context context, Element parent, C value);

    /**
     * Associate view data with the specified key. If the key is null, the view
     * data will be ignored.
     *
     * @param key the key of the view data
     * @param viewData the view data to associate
     * @see #getViewData(Object)
     */
    public void setViewData(Object key, V viewData) {
        if (key == null) {
            return;
        }

        if (viewData == null) {
            clearViewData(key);
        } else {
            viewDataMap.put(key, viewData);
        }
    }
}