org.rstudio.studio.client.pdfviewer.ui.PageNumberListBox.java Source code

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Here is the source code for org.rstudio.studio.client.pdfviewer.ui.PageNumberListBox.java

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/*
 * PageNumberListBox.java
 *
 * Copyright (C) 2009-12 by RStudio, Inc.
 *
 * Unless you have received this program directly from RStudio pursuant
 * to the terms of a commercial license agreement with RStudio, then
 * this program is licensed to you under the terms of version 3 of the
 * GNU Affero General Public License. This program is distributed WITHOUT
 * ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
 * AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
 *
 */
package org.rstudio.studio.client.pdfviewer.ui;

import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.ListBox;

public class PageNumberListBox extends ListBox implements HasValue<Integer> {
    public PageNumberListBox() {
        super(false);
    }

    public void setPageCount(int value) {
        while (value > getItemCount())
            addItem((getItemCount() + 1) + "");

        while (value < getItemCount())
            removeItem(getItemCount() - 1);
    }

    @Override
    public Integer getValue() {
        if (getSelectedIndex() < 0)
            return null;
        return getSelectedIndex() + 1;
    }

    @Override
    public void setValue(Integer value) {
        setValue(value, true);
    }

    @Override
    public void setValue(Integer value, boolean fireEvents) {
        if (value == null)
            value = 0;
        Integer other = getValue();
        if (other == null)
            other = 0;

        if (other.equals(value))
            return;

        if (value < 0)
            throw new ArrayIndexOutOfBoundsException();
        if (value > getItemCount())
            setPageCount(value);

        // If value is 0 (originally null) then this will be setSelectedIndex(-1),
        // which is desired.
        setSelectedIndex(value - 1);

        if (fireEvents)
            ValueChangeEvent.fire(this, value == 0 ? null : value);
    }

    @Override
    public HandlerRegistration addValueChangeHandler(ValueChangeHandler<Integer> handler) {
        return addHandler(handler, ValueChangeEvent.getType());
    }
}