001    /*--------------------------------------------------------------------------+
002    $Id: ITreeWalker.java 26283 2010-02-18 11:18:57Z juergens $
003    |                                                                          |
004    | Copyright 2005-2010 Technische Universitaet Muenchen                     |
005    |                                                                          |
006    | Licensed under the Apache License, Version 2.0 (the "License");          |
007    | you may not use this file except in compliance with the License.         |
008    | You may obtain a copy of the License at                                  |
009    |                                                                          |
010    |    http://www.apache.org/licenses/LICENSE-2.0                            |
011    |                                                                          |
012    | Unless required by applicable law or agreed to in writing, software      |
013    | distributed under the License is distributed on an "AS IS" BASIS,        |
014    | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
015    | See the License for the specific language governing permissions and      |
016    | limitations under the License.                                           |
017    +--------------------------------------------------------------------------*/
018    package edu.tum.cs.commons.visitor;
019    
020    import java.util.Collection;
021    
022    import edu.tum.cs.commons.error.NeverThrownRuntimeException;
023    
024    /**
025     * Interface for a tree walker, i.e. a class which allows the traversal of a
026     * tree. The implementor has to make sure, that this really is a tree, i.e. for
027     * two different node, the children returned must be disjunctive, and traversing
028     * the tree may not result in loops.
029     * 
030     * @param <T>
031     *            the type used for the nodes of the tree.
032     * @param <X>
033     *            the type of exception thrown. Use
034     *            {@link NeverThrownRuntimeException} if no exception is thrown
035     * 
036     * @author hummelb
037     * @author $Author: juergens $
038     * @version $Rev: 26283 $
039     * @levd.rating GREEN Hash: 701FABCC4E43F428F5B99176C88A1CE5
040     */
041    public interface ITreeWalker<T, X extends Exception> {
042    
043            /**
044             * Returns the children of the given tree node. The returned collection may
045             * not contain duplicate entries.
046             */
047            public Collection<T> getChildren(T node) throws X;
048    }