/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library 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
* Lesser General Public License for more details.
*/
package org.geotools.gui.swing.referencing;
// J2SE dependencies
import java.util.List;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import javax.swing.ComboBoxModel;
import javax.swing.AbstractListModel;
// OpenGIS dependencies
import org.opengis.referencing.AuthorityFactory;
import org.opengis.referencing.FactoryException;
/**
* A list of {@link Code}s. This implementation will try to fetch the codes only when
* first needed. Keep in mind that the collection provided to the constructor may be
* database backed (not a usual implementation from {@code java.util} package), so it
* is worth to do lazy loading here.
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*/
final class CodeList extends AbstractListModel implements ComboBoxModel {
/**
* The authority factory, or {@code null} if disposed.
*/
private AuthorityFactory factory;
/**
* The collection of authority codes, or {@code null} if disposed.
*/
private Collection/*<String>*/ codes;
/**
* An iterator over the codes, or {@code null} if not yet created or disposed.
*/
private Iterator iterator;
/**
* The authority codes as {@link Code} objects.
*/
private final List/*<Code>*/ extracted = new ArrayList();
/**
* The selected item, or {@code null} if none.
*/
private Code selected;
/**
* Creates a list for the given codes.
*/
public CodeList(final AuthorityFactory factory, final Class type) throws FactoryException {
this.factory = factory;
this.codes = factory.getAuthorityCodes(type);
if (!codes.isEmpty()) {
// Note: testing if (!isEmpty()) is much facter than if (size() > 0)
selected = (Code) getElementAt(0);
}
}
/**
* Returns the length of the list.
*/
public int getSize() {
return (codes != null) ? codes.size() : extracted.size();
}
/**
* Returns the value at the specified index.
*
* @todo Change to return type to {@link Code} when we will be allowed to compile for J2SE 1.5.
*/
public Object getElementAt(final int index) {
if (codes != null) {
if (iterator == null) {
iterator = codes.iterator();
}
int size;
while (index >= (size=extracted.size())) {
if (!iterator.hasNext()) {
assert extracted.size() == codes.size();
iterator = null;
codes = null;
factory = null;
break;
}
extracted.add(new Code(factory, (String) iterator.next(), size));
}
}
return (index>=0 && index<extracted.size()) ? extracted.get(index) : null;
}
/**
* Returns the selected item.
*
* @todo Change to return type to {@link Code} when we will be allowed to compile for J2SE 1.5.
*/
public Object getSelectedItem() {
return selected;
}
/**
* Set the selected item.
*/
public void setSelectedItem(final Object code) {
selected = (Code) code;
int index = selected.index;
fireContentsChanged(this, index, index);
}
/**
* Returns an item that can be used as a prototype in a combo box. This operation is
* expansive and should be run only once.
*
* @see javax.swing.JComboBox#setPrototypeDisplayValue
*/
public String getPrototypeItem() {
final int size = getSize();
String prototype = "";
for (int i=0; i<size; i++) {
final String candidate = getElementAt(i).toString();
if (candidate.length() > prototype.length()) {
prototype = candidate;
}
}
return prototype;
}
}