constraintinfo.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.impl.sql.execute.ConstraintInfo

   Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable.

   Licensed 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.execute;

import org.apache.derby.iapi.sql.dictionary.ConsInfo;
import org.apache.derby.iapi.sql.dictionary.DataDictionary;
import org.apache.derby.iapi.sql.dictionary.SchemaDescriptor;
import org.apache.derby.iapi.sql.dictionary.TableDescriptor;
import org.apache.derby.catalog.UUID;

import org.apache.derby.iapi.error.StandardException;

import org.apache.derby.iapi.services.io.StoredFormatIds;
import org.apache.derby.iapi.services.io.FormatIdUtil;
import org.apache.derby.iapi.services.io.ArrayUtil;
import org.apache.derby.iapi.services.io.Formatable;

import org.apache.derby.iapi.services.sanity.SanityManager;

import java.io.ObjectOutput;
import java.io.ObjectInput;
import java.io.IOException;
/**
 * This is a simple class used to store the run time information
 * about a constraint.
 *
 * @author jamie
 */
public class ConstraintInfo implements ConsInfo
{
	/********************************************************
	**
	**	This class implements Formatable. That means that it
	**	can write itself to and from a formatted stream. If
	**	you add more fields to this class, make sure that you
	**	also write/read them with the writeExternal()/readExternal()
	**	methods.
	**
	**	If, inbetween releases, you add more fields to this class,
	**	then you should bump the version number emitted by the getTypeFormatId()
	**	method.  OR, since this is something that is used
	**	in stored prepared statements, it is ok to change it
	**	if you make sure that stored prepared statements are
	**	invalidated across releases.
	**
	********************************************************/

	/*
	** See the constructor for the meaning of these fields
	*/
	private String			tableName;
	private SchemaDescriptor	tableSd;
	private UUID				tableSchemaId;
	private String[]			columnNames;
	private int 				raDeleteRule;
	private int					raUpdateRule;


	/**
	 * Niladic constructor for Formattable
	 */
	public ConstraintInfo() {}

	/**
	 * Consructor
	 *
	 */
	public ConstraintInfo(
							String				tableName,
							SchemaDescriptor	tableSd,
							String[]			columnNames,
							int                 raDeleteRule,
							int                 raUpdateRule
						)
	{
		this.tableName = tableName;
		this.tableSd = tableSd;
		this.columnNames = columnNames;
		this.raDeleteRule  = raDeleteRule;
		this.raUpdateRule  = raUpdateRule;
	}

	//////////////////////////////////////////////
	//
	// FORMATABLE
	//
	//////////////////////////////////////////////
	/**
	 * Write this object out
	 *
	 * @param out write bytes here
	 *
 	 * @exception IOException thrown on error
	 */
	public void writeExternal(ObjectOutput out) throws IOException
	{
		out.writeObject(tableName);
		if (tableSd == null)
		{
			out.writeBoolean(false);
		}
		else
		{
			out.writeBoolean(true);
			out.writeObject(tableSd.getUUID());
		}

		if (columnNames == null)
		{
			out.writeBoolean(false);
		}
		else
		{
			out.writeBoolean(true);
			ArrayUtil.writeArrayLength(out, columnNames);
			ArrayUtil.writeArrayItems(out, columnNames);
		}

		//write referential actions for delete and update
		out.writeInt(raDeleteRule);
		out.writeInt(raUpdateRule);
	}

	/**
	 * Read this object from a stream of stored objects.
	 *
	 * @param in read this.
	 *
	 * @exception IOException					thrown on error
	 * @exception ClassNotFoundException		thrown on error
	 */
	public void readExternal(ObjectInput in)
		throws IOException, ClassNotFoundException
	{
		tableName = (String)in.readObject();
		if (in.readBoolean())
		{
			tableSchemaId = (UUID)in.readObject();
		}

		if (in.readBoolean())
		{
			columnNames = new String[ArrayUtil.readArrayLength(in)];
			ArrayUtil.readArrayItems(in, columnNames);
		}

		//read referential actions for delete and update
		raDeleteRule = in.readInt();
		raUpdateRule = in.readInt();
	}
	
	/**
	 * Get the formatID which corresponds to this class.
	 *
	 *	@return	the formatID of this class
	 */
	public	int	getTypeFormatId()	{ return StoredFormatIds.CONSTRAINT_INFO_V01_ID; }

	//////////////////////////////////////////////////////////////
	//
	// Misc
	//
	//////////////////////////////////////////////////////////////
	public String toString()
	{
		if (SanityManager.DEBUG)
		{
			StringBuffer str = new StringBuffer();
			str.append("Referencing ");
			str.append(tableName);
			if (columnNames != null)
			{
				str.append("(");
				for (int i = 0; i < columnNames.length; i++)
				{
					if (i > 0)
						str.append(",");

					str.append(columnNames[i]);
				}
				str.append(")");
			}	
		
			return str.toString();
		}
		else
		{
			return "";
		}
	}

	public SchemaDescriptor getReferencedTableSchemaDescriptor(DataDictionary dd)
		throws StandardException
	{
		if (tableSd != null)
		{
			return tableSd;
		}
		else
		{
			return dd.getSchemaDescriptor(tableSchemaId, null);
		}
	}
			
	public TableDescriptor getReferencedTableDescriptor(DataDictionary dd)
		throws StandardException
	{
		if (tableName == null)
		{
			return null;
		}
	
		return dd.getTableDescriptor(tableName, 
				getReferencedTableSchemaDescriptor(dd));
	}

	/**
	  *	This ConsInfo describes columns in a referenced table. What are
	  *	their names?
	  *
	  *	@return	array of referenced column names
	  */
	public String[] getReferencedColumnNames()
	{ return columnNames; }

	/**
	  *	Get the name of the table that these column live in.
	  *
	  *	@return	referenced table name
	  */
	public String getReferencedTableName()
	{ return tableName; }

	/**
	  *	Get the referential Action for an Update.
	  *
	  *	@return	referential Action for update
	  */
	public int getReferentialActionUpdateRule()
	{ return raUpdateRule; }

	
	/**
	  *	Get the referential Action for a Delete.
	  *
	  *	@return	referential Action Delete rule
	  */
	public int getReferentialActionDeleteRule()
	{ return raDeleteRule; }



}