001    /*
002    // $Id: ParseTreeNode.java 482 2012-01-05 23:27:27Z jhyde $
003    //
004    // Licensed to Julian Hyde under one or more contributor license
005    // agreements. See the NOTICE file distributed with this work for
006    // additional information regarding copyright ownership.
007    //
008    // Julian Hyde licenses this file to you under the Apache License,
009    // Version 2.0 (the "License"); you may not use this file except in
010    // compliance with the License. You may obtain a copy of the License at:
011    //
012    // http://www.apache.org/licenses/LICENSE-2.0
013    //
014    // Unless required by applicable law or agreed to in writing, software
015    // distributed under the License is distributed on an "AS IS" BASIS,
016    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017    // See the License for the specific language governing permissions and
018    // limitations under the License.
019    */
020    package org.olap4j.mdx;
021    
022    import org.olap4j.type.Type;
023    
024    /**
025     * Node in a parse tree representing a parsed MDX statement.
026     *
027     * <p>To convert a parse tree to an MDX string, use a {@link ParseTreeWriter}
028     * and the {@link #unparse(ParseTreeWriter)} method.
029     *
030     * @author jhyde
031     * @version $Id: ParseTreeNode.java 482 2012-01-05 23:27:27Z jhyde $
032     * @since Jun 4, 2007
033     */
034    public interface ParseTreeNode {
035        /**
036         * Accepts a visitor to this MDX parse tree node.
037         *
038         * <p>The implementation should generally dispatches to the
039         * {@link ParseTreeVisitor#visit} method appropriate to the type of expression.
040         *
041         * @param visitor Visitor
042         * @return T, the specific return type of the visitor
043         */
044        <T> T accept(ParseTreeVisitor<T> visitor);
045    
046        /**
047         * Returns the type of this expression.
048         *
049         * <p>Returns null if this node is not an expression, for instance a
050         * <code>SELECT</code> node.
051         *
052         * @return type of this expression
053         */
054        Type getType();
055    
056        /**
057         * Converts this node into MDX text.
058         *
059         * @param writer Parse tree writer
060         */
061        void unparse(ParseTreeWriter writer);
062    
063        /**
064         * Returns the region of the source code which this node was created from,
065         * if it was created by parsing.
066         *
067         * <p>A non-leaf node's region will encompass the regions of all of its
068         * children. For example, a the region of a function call node
069         * <code>Crossjoin([Gender], {[Store].[USA]})</code> stretches from
070         * the first character of the function name to the closing parenthesis.
071         *
072         * <p>Region may be null, if the node was created programmatically, not
073         * from a piece of source code.
074         *
075         * @return Region of the source code this node was created from, if it was
076         * created by parsing
077         */
078        ParseRegion getRegion();
079    
080        /**
081         * Creates a deep copy of this ParseTreeNode object.
082         *
083         * <p>Note: implementing classes can return the concrete type instead
084         * of ParseTreeNode (using Java 1.5 covariant return types)
085         *
086         * @return The deep copy of this ParseTreeNode
087         */
088        ParseTreeNode deepCopy();
089    
090    }
091    
092    // End ParseTreeNode.java