ExtendedListModel.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.uitools.swing;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.AbstractListModel;
import javax.swing.ListModel;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;

/**
 * This wrapper extends a ListModel with fixed lists of items on either end.
 *
 * NB: Be careful using or wrapping this list model, since the "extended"
 * items may be unexpected by the client code or wrapper.
 */
public class ExtendedListModel
    extends AbstractListModel
    implements ListModel
{
    // **************** Variables *********************************************

    /** The wrapped list model */
    protected ListModel listModel;

    /** The items "prepended" to the wrapped model */
    protected List prefix;

    /** The items "appended" to the wrapped model */
    protected List suffix;


    // **************** Constructors ******************************************

    /**
     * Extend the specified list model with a prefix and suffix.
     */
    public ExtendedListModel(List prefix, ListModel listModel, List suffix) {
        super();
        this.initialize(listModel);
        this.prefix = new ArrayList(prefix);
        this.suffix = new ArrayList(suffix);
    }

    /**
     * Extend the specified list model with a singleton prefix and suffix.
     */
    public ExtendedListModel(Object prefix, ListModel listModel, Object suffix) {
        this(Collections.singletonList(prefix), listModel, Collections.singletonList(suffix));
    }

    /**
     * Extend the specified list model with a prefix.
     */
    public ExtendedListModel(List prefix, ListModel listModel) {
        this(prefix, listModel, Collections.EMPTY_LIST);
    }

    /**
     * Extend the specified list model with a singleton prefix.
     */
    public ExtendedListModel(Object prefix, ListModel listModel) {
        this(Collections.singletonList(prefix), listModel, Collections.EMPTY_LIST);
    }

    /**
     * Extend the specified list model with a suffix.
     */
    public ExtendedListModel(ListModel listModel, List suffix) {
        this(Collections.EMPTY_LIST, listModel, suffix);
    }

    /**
     * Extend the specified list with a singleton suffix.
     */
    public ExtendedListModel(ListModel listModel, Object suffix) {
        this(Collections.EMPTY_LIST, listModel, Collections.singletonList(suffix));
    }

    /**
     * Extend the specified list model with a prefix containing a single null item.
     */
    public ExtendedListModel(ListModel listModel) {
        this(Collections.singletonList(null), listModel, Collections.EMPTY_LIST);
    }


    // **************** Initialization ****************************************

    protected void initialize(ListModel model) {
        this.listModel = model;
        this.listModel.addListDataListener(this.buildListDataListener());
    }

    protected ListDataListener buildListDataListener() {
        return new ListDataListener() {
            public void intervalAdded(ListDataEvent e) {
                ExtendedListModel.this.intervalAdded(e);
            }
            public void intervalRemoved(ListDataEvent e) {
                ExtendedListModel.this.intervalRemoved(e);
            }
            public void contentsChanged(ListDataEvent e) {
                ExtendedListModel.this.contentsChanged(e);
            }
            public String toString() {
                return "list data listener";
            }
        };
    }

    void intervalAdded(ListDataEvent e) {
        // Add prefix size to indices
        int prefixSize = this.prefix.size();
        this.fireIntervalAdded(this, e.getIndex0() + prefixSize, e.getIndex1() + prefixSize);
    }

    void intervalRemoved(ListDataEvent e) {
        // Add prefix size to indices
        int prefixSize = this.prefix.size();
        this.fireIntervalRemoved(this, e.getIndex0() + prefixSize, e.getIndex1() + prefixSize);
    }

    void contentsChanged(ListDataEvent e) {
        // Add prefix size to indices, unless the index is -1,
        // because for some reason, -1 is special
        int prefixSize = this.prefix.size();
        int newIndex0 = (e.getIndex0() == -1) ? -1 : e.getIndex0() + prefixSize;
        int newIndex1 = (e.getIndex1() == -1) ? -1 : e.getIndex1() + prefixSize;
        this.fireContentsChanged(this, newIndex0, newIndex1);
    }


    // **************** ListModel implementation ******************************

    public int getSize() {
        return this.prefix.size() + this.listModel.getSize() + this.suffix.size();
    }

    public Object getElementAt(int index) {
        int prefixSize = this.prefix.size();

        if (index < prefixSize) {
            return this.prefix.get(index);
        }
        else if (index >= prefixSize + this.listModel.getSize()) {
            return this.suffix.get(index - (prefixSize + this.listModel.getSize()));
        }
        else {
            return this.listModel.getElementAt(index - prefixSize);
        }
    }
}