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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package javafx.beans.property;

import javafx.beans.InvalidationListener;
import javafx.beans.value.ChangeListener;

import com.sun.javafx.binding.ExpressionHelper;

/**
 * Base class for all readonly properties wrapping a {@code String}. This class provides a default
 * implementation to attach listener.
 *
 * @see ReadOnlyStringProperty
 * @since JavaFX 2.0
 */
public abstract class ReadOnlyStringPropertyBase extends ReadOnlyStringProperty {

    ExpressionHelper<String> helper;

    @Override
    public void addListener(InvalidationListener listener) {
        helper = ExpressionHelper.addListener(helper, this, listener);
    }

    @Override
    public void removeListener(InvalidationListener listener) {
        helper = ExpressionHelper.removeListener(helper, listener);
    }

    @Override
    public void addListener(ChangeListener<? super String> listener) {
        helper = ExpressionHelper.addListener(helper, this, listener);
    }

    @Override
    public void removeListener(ChangeListener<? super String> listener) {
        helper = ExpressionHelper.removeListener(helper, listener);
    }

    /**
     * Sends notifications to all attached
     * {@link javafx.beans.InvalidationListener InvalidationListeners} and
     * {@link javafx.beans.value.ChangeListener ChangeListeners}.
     *
     * This method needs to be called, if the value of this property changes.
     */
    protected void fireValueChangedEvent() {
        ExpressionHelper.fireValueChangedEvent(helper);
    }

}
