java/engine/org/apache/derby/impl/sql/compile/WindowDefinitionNode.java

/*

   Derby - Class org.apache.derby.impl.sql.compile.WindowDefinitionNode

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to you under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */

package org.apache.derby.impl.sql.compile;

import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.reference.SQLState;
import org.apache.derby.iapi.services.context.ContextManager;
import org.apache.derby.shared.common.sanity.SanityManager;

/**
 * This class represents an OLAP window definition.
 */
public final class WindowDefinitionNode extends WindowNode
{
    /**
     * True of the window definition was inlined.
     */
    private boolean inlined;

    /**
     * The order by list if the window definition contains a <window order
     * clause>, else null.
     */
    private OrderByList orderByList;

    /**
     * Constructor.
     *
     * @param windowName  The window name, null if in-lined definition
     * @param orderByList ORDER BY list
     * @param cm          The context manager
     * @exception StandardException
     */
    WindowDefinitionNode(String         windowName,
                         OrderByList    orderByList,
                         ContextManager cm) throws StandardException {
        super(windowName != null ? windowName : "IN-LINE", cm);
        this.orderByList = orderByList;

        if (windowName != null) {
            inlined = false;
        } else {
            inlined = true;
        }

        if (orderByList != null) {
            throw StandardException.newException(SQLState.NOT_IMPLEMENTED,
                                                 "WINDOW/ORDER BY");
        }
    }


    /**
     * java.lang.Object override.
     * @see QueryTreeNode#toString
     */
    @Override
    public String toString() {
        return ("name: " + getName() + "\n" +
                "inlined: " + inlined + "\n" +
                "()\n");
    }



    /**
     * QueryTreeNode override. Prints the sub-nodes of this object.
     * @see QueryTreeNode#printSubNodes
     *
     * @param depth     The depth of this node in the tree
     */
    @Override
    public void printSubNodes(int depth)
    {
        if (SanityManager.DEBUG)
        {
            super.printSubNodes(depth);

            if (orderByList != null) {
                printLabel(depth, "orderByList: "  + depth);
                orderByList.treePrint(depth + 1);
            }
        }
    }


    /**
     * Used to merge equivalent window definitions.
     *
     * @param wl list of window definitions
     * @return an existing window definition from wl, if 'this' is equivalent
     * to a window in wl.
     */
    WindowDefinitionNode findEquivalentWindow(WindowList wl) {
        for (WindowDefinitionNode old : wl) {
            if (isEquivalent(old)) {
                return old;
            }
        }
        return null;
    }



    /**
     * @return true if the window specifications are equal; no need to create
     * more than one window then.
     */
    private boolean isEquivalent(WindowDefinitionNode other) {
        if (orderByList == null && other.getOrderByList() == null) {
            return true;
        }

        if (SanityManager.DEBUG) {
            SanityManager.ASSERT(
                false,
                "FIXME: ordering in windows not implemented yet");
        }
        return false;
    }



    /**
     * @return the order by list of this window definition if any, else null.
     */
    OrderByList getOrderByList() {
        return orderByList;
    }
}