net.cbtltd.client.field.datepicker.DateChangeEvent.java Source code

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Here is the source code for net.cbtltd.client.field.datepicker.DateChangeEvent.java

Source

/*
 * 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 net.cbtltd.client.field.datepicker;

import java.util.Date;

import com.google.gwt.event.logical.shared.HasValueChangeHandlers;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.shared.HasHandlers;

/**
 * Creates a new value every time a date is accessed.
 */
class DateChangeEvent extends ValueChangeEvent<Date> {

    /**
     * Fires value change event if the old value is not equal to the new value.
     * Use this call rather than making the decision to short circuit yourself for
     * safe handling of null.
     * 
     * @param <I> the old value type
     * @param <S> The event source
     * @param source the source of the handlers
     * @param oldValue the oldValue, may be null
     * @param newValue the newValue, may be null
     */
    public static <S extends HasValueChangeHandlers<Date> & HasHandlers> void fireIfNotEqualDates(S source,
            Date oldValue, Date newValue) {
        if (ValueChangeEvent.shouldFire(source, oldValue, newValue)) {
            source.fireEvent(new DateChangeEvent(newValue));
        }
    }

    /**
     * Creates a new date value change event.
     * 
     * @param value the value
     */
    protected DateChangeEvent(Date value) {
        // The date must be copied in case one handler causes it to change.
        super(CalendarUtil.copyDate(value));
    }

    @Override
    public Date getValue() {
        return CalendarUtil.copyDate(super.getValue());
    }
}