poi/src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/OperationEval.java

54 lines
2.0 KiB
Java

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
/*
* Created on May 8, 2005
*
*/
package org.apache.poi.hssf.record.formula.eval;
/**
* @author Amol S. Deshmukh < amolweb at ya hoo dot com >
*
*/
public interface OperationEval extends Eval {
/*
* Read this, this will make your work easier when coding
* an "evaluate()"
*
* Things to note when implementing evaluate():
* 1. Check the length of operands
* (use "switch(operands[x])" if possible)
*
* 2. The possible Evals that you can get as args to evaluate are one of:
* NumericValueEval, StringValueEval, RefEval, AreaEval
* 3. If it is RefEval, the innerValueEval could be one of:
* NumericValueEval, StringValueEval, BlankEval
* 4. If it is AreaEval, each of the values could be one of:
* NumericValueEval, StringValueEval, BlankEval, RefEval
*
* 5. For numeric functions/operations, keep the result in double
* till the end and before returning a new NumberEval, check to see
* if the double is a NaN - if NaN, return ErrorEval.ERROR_503
*/
public abstract Eval evaluate(Eval[] evals, int srcCellRow, short srcCellCol);
public abstract int getNumberOfOperands();
public abstract int getType();
}