public AndExpression(Exp exp1,
    Exp exp2) 
{
        _exp1 = exp1;
        _exp2 = exp2;
}

Constructor. Supply the expressions to combine.

 public  void acceptVisit(ExpressionVisitor visitor) 
{
        visitor.enter(this);
        _exp1.acceptVisit(visitor);
        _exp2.acceptVisit(visitor);
        visitor.exit(this);
}

 public  void appendTo(Select sel,
    ExpContext ctx,
    ExpState state,
    SQLBuffer buf) 
{
        BinaryOpExpState bstate = (BinaryOpExpState) state;
        boolean paren1 = _exp1 instanceof OrExpression;
        boolean paren2 = _exp2 instanceof OrExpression;
        if (paren1)
            buf.append("(");
        _exp1.appendTo(sel, ctx, bstate.state1, buf);
        if (paren1)
            buf.append(")");
        buf.append(" AND ");
        if (paren2)
            buf.append("(");
        _exp2.appendTo(sel, ctx, bstate.state2, buf);
        if (paren2)
            buf.append(")");
        sel.append(buf, state.joins);
}

 public ExpState initialize(Select sel,
    ExpContext ctx,
    Map contains) 
{
        ExpState s1 = _exp1.initialize(sel, ctx, contains);
        ExpState s2 = _exp2.initialize(sel, ctx, contains);
        return new BinaryOpExpState(sel.and(s1.joins, s2.joins), s1, s2);
}

 public  void selectColumns(Select sel,
    ExpContext ctx,
    ExpState state,
    boolean pks) 
{
        BinaryOpExpState bstate = (BinaryOpExpState) state;
        _exp1.selectColumns(sel, ctx, bstate.state1, pks);
        _exp2.selectColumns(sel, ctx, bstate.state2, pks);
}