/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.wizards.datatransfer;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.ui.dialogs.FileSystemElement;
import org.eclipse.ui.model.AdaptableList;
import org.eclipse.ui.wizards.datatransfer.IImportStructureProvider;

/**
 * The <code>MinimizedFileSystemElement</code> is a <code>FileSystemElement</code> that knows
 * if it has been populated or not.
 */
public class MinimizedFileSystemElement extends FileSystemElement {
    private boolean populated = false;

    /**
     * Create a <code>MinimizedFileSystemElement</code> with the supplied name and parent.
     * @param name the name of the file element this represents
     * @param parent the containing parent
     * @param isDirectory indicated if this could have children or not
     */
    public MinimizedFileSystemElement(String name, FileSystemElement parent,
            boolean isDirectory) {
        super(name, parent, isDirectory);
    }

    /**
     * Returns a list of the files that are immediate children. Use the supplied provider
     * if it needs to be populated.
     * of this folder.
     */
    public AdaptableList getFiles(IImportStructureProvider provider) {
        if (!populated) {
            populate(provider);
        }
        return super.getFiles();
    }

    /**
     * Returns a list of the folders that are immediate children. Use the supplied provider
     * if it needs to be populated.
     * of this folder.
     */
    public AdaptableList getFolders(IImportStructureProvider provider) {
        if (!populated) {
            populate(provider);
        }
        return super.getFolders();
    }

    /**
     * Return whether or not population has happened for the receiver.
     */
    boolean isPopulated() {
        return this.populated;
    }

    /**
     * Return whether or not population has not happened for the receiver.
     */
    boolean notPopulated() {
        return !this.populated;
    }

    /**
     * Populate the files and folders of the receiver using the suppliec structure provider.
     * @param provider org.eclipse.ui.wizards.datatransfer.IImportStructureProvider
     */
    private void populate(IImportStructureProvider provider) {

        Object fileSystemObject = getFileSystemObject();

        List children = provider.getChildren(fileSystemObject);
        if (children == null) {
            children = new ArrayList(1);
        }
        Iterator childrenEnum = children.iterator();
        while (childrenEnum.hasNext()) {
            Object child = childrenEnum.next();

            String elementLabel = provider.getLabel(child);
            //Create one level below
            MinimizedFileSystemElement result = new MinimizedFileSystemElement(
                    elementLabel, this, provider.isFolder(child));
            result.setFileSystemObject(child);
        }
        setPopulated();
    }

    /**
     * Set whether or not population has happened for the receiver to true.
     */
   public void setPopulated() {
        this.populated = true;
    }
}