G(arbage) C(ollected) X(Query) Engine: operandexpression.h Source File

00001 
00002 /*
00003  | Author: Michael Schmidt;
00004  |         Gunnar Jehl 
00005  |
00006  | ************************* SOFTWARE LICENSE AGREEMENT ***********************
00007  | This source code is published under the BSD License.
00008  |
00009  | See file 'LICENSE.txt' that comes with this distribution or
00010  | http://dbis.informatik.uni-freiburg.de/index.php?project=GCX/license.php
00011  | for the full license agreement.
00012  |
00013  | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00014  | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00015  | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00016  | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
00017  | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00018  | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00019  | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00020  | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00021  | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00022  | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00023  | POSSIBILITY OF SUCH DAMAGE.
00024  | ****************************************************************************
00025 */
00026 
00035 #ifndef OPERANDEXPRESSION_H
00036 #define OPERANDEXPRESSION_H
00037 
00038 #include "expression.h"
00039 #include "value.h"
00040 
00054 class OperandExpression:public Expression {
00055 
00056   public:
00062     OperandExpression(EXP_TYPE _type, EXP_TYPE _op_type);
00063 
00067      virtual ~ OperandExpression();
00068 
00076     virtual bool isSingleValued() = 0;
00077 
00086     virtual void prepareOperand(OutputStream & eos, Environment * env,
00087                                 unsigned modus) = 0;
00088 
00094     virtual void unprepareOperand() = 0;
00095 
00101     virtual Value *getNextValue() = 0;
00102 
00108     inline const EXP_TYPE getOperandType() {
00109         return op_type;
00110   } protected:
00115     EXP_TYPE op_type;
00116 
00121     bool initial;
00122 
00127     Value cur_val;
00128 };
00129 
00130 #endif // OPERANDEXPRESSION_H