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- /*
- * Copyright (c) 2008, Manuel Mausz <manuel at mausz.at>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * * Neither the name of the copyright holders nor the
- * names of its contributors may be used to endorse or promote products
- * derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
- * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
- * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
- * DAMAGE.
- */
-
- import java.util.Stack;
- import java.util.HashMap;
- import java.util.Iterator;
-
- /**
- * Implements a RPN Calculator (stack based)
- * See http://en.wikipedia.org/wiki/Reverse_Polish_notation for more info
- *
- * @version 1.0
- * @author Manuel Mausz (manuel at mausz.at)
- * @author http://manuel.mausz.at/
- */
- class Rechner implements UPNRechner
- {
- private Stack<Double> stack = new Stack<Double>();
-
- /**
- * add operation to "supported operations"-list
- *
- * @param op operation object
- */
- public void addOperation(UPNOperation op)
- {
- operations.put(op.getOperationSymbol(), op);
- }
-
- /**
- * get operation mapped to the specified operation-symbol
- *
- * @param op operation symbol
- * @return operation object or null
- */
- {
- return (operations.containsKey(op)) ? operations.get(op) : null;
- }
-
- /**
- * push operand onto internal stack
- *
- * @param val value
- */
- {
- stack.push(val);
- }
-
- /**
- * executes operation assigned to operation symbol
- *
- * @param opstr operation symbol
- * @throws InvalidOperationException if operation isn't supported
- * @throws InvalidParameterException
- */
- throws InvalidOperationException, InvalidParameterException
- {
- UPNOperation op = getOperation(opstr);
- if (op == null)
- throw new InvalidOperationException("Operator doesn't exist");
- op.execute(stack);
- }
-
- /**
- * returns internal stack converted to string
- *
- * @return string
- */
- {
- while(it.hasNext())
- str += it.next() + " ";
- return str;
- }
- }
-