eclox.ui.editor.advanced.NavigableSelection.java Source code

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Here is the source code for eclox.ui.editor.advanced.NavigableSelection.java

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/*******************************************************************************
 * Copyright (C) 2003-2007, 2013, Guillaume Brocker
 *
 * 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:
 *     Guillaume Brocker - Initial API and implementation
 *
 ******************************************************************************/

package eclox.ui.editor.advanced;

import java.util.Iterator;
import java.util.List;
import java.util.Stack;
import java.util.Vector;

import org.eclipse.jface.viewers.IStructuredSelection;

/**
 * Implements a selection that provides the history of all selected
 * items as well as the navigation among those items.
 *
 * @author gbrocker
 */
public class NavigableSelection implements IStructuredSelection {

    private Stack<Object> previousElements = new Stack<Object>(); ///< Contains all previously selected elements.
    private Stack<Object> nextElements = new Stack<Object>(); ///< Contains all next selected elements.
    private Vector<Object> elements = new Vector<Object>(); ///< References the current element of the selection.

    /**
     * @brief   Builds a new selection that holds the given object.
     *
     * @param   object   the new object to select
     *
     * @return   the new selection
     */
    public NavigableSelection select(Object object) {
        NavigableSelection result;
        if (getFirstElement() != object) {
            result = new NavigableSelection();
            if (isEmpty() == false) {
                result.previousElements.addAll(previousElements);
                result.previousElements.push(elements.firstElement());
            }
            result.elements.add(object);
        } else {
            result = this;
        }
        return result;
    }

    /**
     * @brief   Retrieves the collection of items that follow the current item
     *          in the history.
     *
     * @return   a stack of items
     */
    public Stack<Object> getNextElements() {
        return nextElements;
    }

    /**
     * @brief   Builds the selection that follows in the history.
     *
     * @return   a selection or null if none
     */
    public NavigableSelection getNextSelection() {
        NavigableSelection result = null;
        if (nextElements.empty() == false) {
            result = new NavigableSelection();
            result.previousElements.addAll(previousElements);
            result.previousElements.push(elements.firstElement());
            result.elements.add(nextElements.peek());
            result.nextElements.addAll(nextElements);
            result.nextElements.pop();
        }
        return result;
    }

    /**
     * @brief   Retrieves the collection of items that preceed the current item
     *          in the history.
     *
     * @return   a stack of items
     */
    public Stack<Object> getPreviousElements() {
        return previousElements;
    }

    /**
     * @brief   Builds the selection that preceeds in the history.
     *
     * @return   a selection or null if none
     */
    public NavigableSelection getPreviousSelection() {
        NavigableSelection result = null;
        if (previousElements.empty() == false) {
            result = new NavigableSelection();
            result.previousElements.addAll(previousElements);
            result.previousElements.pop();
            result.elements.add(previousElements.peek());
            result.nextElements.addAll(nextElements);
            result.nextElements.push(elements.firstElement());
        }
        return result;
    }

    /**
     * @see org.eclipse.jface.viewers.ISelection#isEmpty()
     */
    public boolean isEmpty() {
        return elements.isEmpty();
    }

    /**
     * Retrieves the selected element.
     *
     * @see org.eclipse.jface.viewers.IStructuredSelection#getFirstElement()
     */
    public Object getFirstElement() {
        return elements.isEmpty() ? null : elements.firstElement();
    }

    /**
     * @see org.eclipse.jface.viewers.IStructuredSelection#iterator()
     */
    public Iterator<Object> iterator() {
        return elements.iterator();
    }

    /**
     * @see org.eclipse.jface.viewers.IStructuredSelection#size()
     */
    public int size() {
        return elements.size();
    }

    /**
     * @see org.eclipse.jface.viewers.IStructuredSelection#toArray()
     */
    public Object[] toArray() {
        return elements.toArray();
    }

    /**
     * @see org.eclipse.jface.viewers.IStructuredSelection#toList()
     */
    public List<Object> toList() {
        return new Vector<Object>(elements);
    }

}