001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  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,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License. 
018     *  
019     */
020    
021    package org.apache.directory.shared.ldap.filter;
022    
023    
024    /**
025     * Root expression node interface which all expression nodes in the filter
026     * expression tree implement.
027     * 
028     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
029     * @version $Revision: 746607 $
030     */
031    public interface ExprNode extends Cloneable
032    {
033        /**
034         * Gets an annotation on the tree by key.
035         * 
036         * @param key the annotation key.
037         * @return the annotation value.
038         */
039        Object get( Object key );
040    
041    
042        /**
043         * Sets a annotation key to a value.
044         * 
045         * @param key the annotation key.
046         * @param value the annotation value.
047         */
048        void set( String key, Object value );
049    
050    
051        /**
052         * Tests to see if this node is a leaf or branch node.
053         * 
054         * @return true if the node is a leaf,false otherwise
055         */
056        boolean isLeaf();
057    
058        
059        /**
060         * Gets the assertion type of this node. Make it possible to use switch
061         * statements on the node type.
062         * 
063         * @return the assertion type
064         */
065        AssertionType getAssertionType();
066    
067        /**
068         * Recursively appends the refinement string representation of this node and its
069         * descendants in prefix notation to a buffer.
070         *
071         * TODO - Why is this here? Why not put it in some utility class?
072         * 
073         * @param buf the buffer to append to.
074         * @return The buffer in which the refinement has been appended
075         * @throws UnsupportedOperationException if this node isn't a part of a refinement.
076         * @return the refinement buffer
077         */
078        StringBuilder printRefinementToBuffer( StringBuilder buf );
079        
080        
081        /**
082         * Element/node accept method for visitor pattern.
083         * 
084         * @param visitor the filter expression tree structure visitor
085         * TODO - what is this modified element ?
086         * @return the modified element
087         */
088        Object accept( FilterVisitor visitor );
089        
090        
091        /**
092         * Clone the object
093         * @return
094         */
095        ExprNode clone();
096    }