package org.litesoft.orsup.base;

import java.io.*;

import org.litesoft.orsup.selection.*;

public abstract class PersistentObjectUniqueKey implements Serializable
{
    static final long serialVersionUID = -112354983213548313L;

    protected static final char NULL_CHAR = '!';
    protected static final char DATA_CHAR = '+';
    private static final String NULL_STRING = "" + NULL_CHAR;

    private transient Integer mCachedHashCode = null;
    private transient String mCachedToString = null;

    public final boolean equals( Object pThem )
    {
        return (this == pThem) || ((pThem instanceof PersistentObjectUniqueKey) &&
                                   equalsNotNullNotUs( (PersistentObjectUniqueKey) pThem ));
    }

    public final boolean equals( PersistentObjectUniqueKey pThem )
    {
        return (this == pThem) || ((pThem != null) && equalsNotNullNotUs( pThem ));
    }

    public final int hashCode()
    {
        if ( mCachedHashCode == null )
        {
            mCachedHashCode = calcHashCode(); // Boxing
        }
        return mCachedHashCode; // Unboxing
    }

    public final String toString()
    {
        if ( mCachedToString == null )
        {
            mCachedToString = generateToStringForConstructor();
        }
        return mCachedToString;
    }

    public static Long nullifyfromStringToLong( String pIDfromString )
            throws IllegalArgumentException
    {
        pIDfromString = nullifyfromString( pIDfromString );
        return (pIDfromString == null) ? 0L : new Long( pIDfromString );
    }

    public static String nullifyfromString( String pIDfromString )
            throws IllegalArgumentException
    {
        if ( NULL_STRING.equals( pIDfromString ) )
        {
            return null;
        }
        if ( (pIDfromString != null) && (pIDfromString.length() > 0) &&
             (pIDfromString.charAt( 0 ) == DATA_CHAR) )
        {
            return pIDfromString.substring( 1 );
        }
        throw new IllegalArgumentException( "Unacceptable encoding of ID: '" + pIDfromString + "'" );
    }

    protected final String idToString( Object pID )
    {
        return (pID == null) ? NULL_STRING : "" + DATA_CHAR + pID;
    }

    abstract protected int calcHashCode();

    abstract protected boolean equalsNotNullNotUs( PersistentObjectUniqueKey pThem );

    abstract protected String generateToStringForConstructor();

    abstract public WhereClause convertToWC();
}