trunk/ldap/model/src/main/java/org/apache/directory/api/ldap/model/filter/ExprNode.java

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 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *  
 *    http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.directory.api.ldap.model.filter;


/**
 * Root expression node interface which all expression nodes in the filter
 * expression tree implement.
 * 
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 */
public interface ExprNode extends Cloneable
{
    /**
     * Gets an annotation on the tree by key.
     * 
     * @param key the annotation key.
     * @return the annotation value.
     */
    Object get( Object key );


    /**
     * Sets a annotation key to a value.
     * 
     * @param key the annotation key.
     * @param value the annotation value.
     */
    void set( String key, Object value );


    /**
     * Tests to see if this node is a leaf or branch node.
     * 
     * @return true if the node is a leaf,false otherwise
     */
    boolean isLeaf();


    /**
     * Tells if this Node is Schema aware.
     * 
     * @return true if the Node is SchemaAware
     */
    boolean isSchemaAware();


    /**
     * Gets the assertion type of this node. Make it possible to use switch
     * statements on the node type.
     * 
     * @return the assertion type
     */
    AssertionType getAssertionType();


    /**
     * Recursively appends the refinement string representation of this node and its
     * descendants in prefix notation to a buffer.
     *
     * TODO - Why is this here? Why not put it in some utility class?
     * 
     * @param buf the buffer to append to.
     * @return The buffer in which the refinement has been appended
     * @throws UnsupportedOperationException if this node isn't a part of a refinement.
     */
    StringBuilder printRefinementToBuffer( StringBuilder buf ) throws UnsupportedOperationException;


    /**
     * Element/node accept method for visitor pattern.
     * 
     * @param visitor the filter expression tree structure visitor
     * TODO - what is this modified element ?
     * @return the modified element
     */
    Object accept( FilterVisitor visitor );


    /**
     * Clone this expression node.
     * 
     * @return the cloned expression node
     */
    ExprNode clone();
}