package org.litesoft.orsup.base;

import org.litesoft.db.*;
import org.litesoft.orsup.selection.*;

public abstract class POFilteringWhereClause
{
    abstract public boolean selects( PersistentObject pPO )
            throws DBException;

    public WhereClauseType getType()
    {
        return mType;
    }

    private WhereClauseType mType;

    protected POFilteringWhereClause( WhereClauseType pType )
    {
        mType = pType;
    }

    /**
     * Generate a Debug friendly representation.<p>
     *
     * @return a String for Debuging.
     */
    public final String toString()
    {
        StringBuilder sb = new StringBuilder( "Filter " );
        appendPO( sb );
        sb.append( "Where " );
        toStringHelper( sb );
        return sb.toString();
    }

    /**
     * Helper method for <b>toString()</b> that provides a more efficient
     * mechanism for the recursive decent of a WhereClause <i>tree</i>.<p>
     *
     * @param pSB the StringBuilder to build the WhereClause into.<p>
     *
     * @see #toString()
     */
    protected abstract void appendPO( StringBuilder pSB );

    /**
     * Helper method for <b>toString()</b> that provides a more efficient
     * mechanism for the recursive decent of a WhereClause <i>tree</i>.<p>
     *
     * @param pSB the StringBuilder to build the WhereClause into.<p>
     *
     * @see #toString()
     */
    protected abstract void toStringHelper( StringBuilder pSB );

    /**
     * Helper method for <b>toStringHelper()</b> that adds a parenthesized
     * nested WhereClause.<p>
     *
     * @param pSB     the StringBuilder to build the WhereClause into.
     * @param pFilter the nested WhereClause to wrap with parenthesizes
     *                and append.<p>
     *
     * @see #toStringHelper(StringBuilder)
     */
    protected static void toStringHelperParenthesizer( StringBuilder pSB, POFilteringWhereClause pFilter )
    {
        pSB.append( '(' );
        pFilter.toStringHelper( pSB );
        pSB.append( ')' );
    }

    /**
     * Helper method for <b>toStringHelper()</b> that adds a prefix and then
     * parenthesizes a nested WhereClause.<p>
     *
     * @param pSB     the StringBuilder to build the WhereClause into.
     * @param pPreFix the prefix to append.
     * @param pFilter the nested WhereClause to wrap with parenthesizes
     *                and append.<p>
     *
     * @see #toStringHelper(StringBuilder)
     */
    protected static void toStringHelperParenthesizer( StringBuilder pSB, String pPreFix,
                                                       POFilteringWhereClause pFilter )
    {
        pSB.append( pPreFix );
        pSB.append( ' ' );
        toStringHelperParenthesizer( pSB, pFilter );
    }
}