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

/*

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

   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.services.context.ContextManager;
import org.apache.derby.shared.common.sanity.SanityManager;

/**
 * A TableElementNode is an item in a TableElementList, and represents
 * a single table element such as a column or constraint in a CREATE TABLE
 * or ALTER TABLE statement.
 *
 */

class TableElementNode extends QueryTreeNode
{
    /////////////////////////////////////////////////////////////////////////
	//
	//	CONSTANTS
	//
	/////////////////////////////////////////////////////////////////////////

	public	static	final	int	AT_UNKNOWN						= 0;
	public	static	final	int	AT_ADD_FOREIGN_KEY_CONSTRAINT	= 1;
	public	static	final	int	AT_ADD_PRIMARY_KEY_CONSTRAINT	= 2;
	public	static	final	int	AT_ADD_UNIQUE_CONSTRAINT		= 3;
	public	static	final	int	AT_ADD_CHECK_CONSTRAINT			= 4;
	public	static	final	int	AT_DROP_CONSTRAINT				= 5;
	public	static	final	int	AT_MODIFY_COLUMN				= 6;
	public	static	final	int	AT_DROP_COLUMN					= 7;
    public  static  final   int AT_MODIFY_CONSTRAINT            = 8;


	/////////////////////////////////////////////////////////////////////////
	//
	//	STATE
	//
	/////////////////////////////////////////////////////////////////////////

	String	name;
	int		elementType;	// simple element nodes can share this class,
							// eg., drop column and rename table/column/index
							// etc., no need for more classes, an effort to
							// minimize footprint

	/////////////////////////////////////////////////////////////////////////
	//
	//	BEHAVIOR
	//
	/////////////////////////////////////////////////////////////////////////

	/**
     * Constructor for a TableElementNode
	 *
	 * @param name	The name of the table element, if any
	 */

    TableElementNode(String name, ContextManager cm)
	{
        super(cm);
        this.name = name;
	}

	/**
	 * Convert this object to a String.  See comments in QueryTreeNode.java
	 * for how this should be done for tree printing.
	 *
	 * @return	This object as a String
	 */
    @Override
	public String toString()
	{
		if (SanityManager.DEBUG)
		{
			return "name: " + name + "\n" +
                "elementType: " + getElementType() + "\n" +
				super.toString();
		}
		else
		{
			return "";
		}
	}

	/**
	 * Does this element have a primary key constraint.
	 *
	 * @return boolean	Whether or not this element has a primary key constraint
	 */
	boolean hasPrimaryKeyConstraint()
	{
		return false;
	}

	/**
	 * Does this element have a unique key constraint.
	 *
	 * @return boolean	Whether or not this element has a unique key constraint
	 */
	boolean hasUniqueKeyConstraint()
	{
		return false;
	}

	/**
	 * Does this element have a foreign key constraint.
	 *
	 * @return boolean	Whether or not this element has a foreign key constraint
	 */
	boolean hasForeignKeyConstraint()
	{
		return false;
	}

	/**
	 * Does this element have a check constraint.
	 *
	 * @return boolean	Whether or not this element has a check constraint
	 */
	boolean hasCheckConstraint()
	{
		return false;
	}

	/**
	 * Does this element have a constraint on it.
	 *
	 * @return boolean	Whether or not this element has a constraint on it
	 */
	boolean hasConstraint()
	{
		return false;
	}

	/**
	 * Get the name from this node.
	 *
	 * @return String	The name.
	 */
    String getName()
	{
		return name;
	}

	/**
	  *	Get the type of this table element.
	  *
	  *	@return	one of the constants at the front of this file
	  */
	int	getElementType()
	{
		if ( hasForeignKeyConstraint() ) { return AT_ADD_FOREIGN_KEY_CONSTRAINT; }
		else if ( hasPrimaryKeyConstraint() ) { return AT_ADD_PRIMARY_KEY_CONSTRAINT; }
		else if ( hasUniqueKeyConstraint() ) { return AT_ADD_UNIQUE_CONSTRAINT; }
		else if ( hasCheckConstraint() ) { return AT_ADD_CHECK_CONSTRAINT; }
		else if ( this instanceof ConstraintDefinitionNode ) { return AT_DROP_CONSTRAINT; }
		else if ( this instanceof ModifyColumnNode )
        {
            if (((ModifyColumnNode)this).kind == ModifyColumnNode.K_DROP_COLUMN)
            {
                return AT_DROP_COLUMN;
            } else {
                return AT_MODIFY_COLUMN;
            }
        }
		else { return elementType; }
	}

}