Fix redundant clear display after unary operation
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
diff --git a/org.eclipse.example.calc/src/org/eclipse/example/calc/internal/ui/Calculator.java b/org.eclipse.example.calc/src/org/eclipse/example/calc/internal/ui/Calculator.java
index db032da..ff2c20f 100644
--- a/org.eclipse.example.calc/src/org/eclipse/example/calc/internal/ui/Calculator.java
+++ b/org.eclipse.example.calc/src/org/eclipse/example/calc/internal/ui/Calculator.java
@@ -37,14 +37,21 @@
private static final long serialVersionUID = 1L;
private String cmd;
+
private boolean clearDisplay;
+
private float value;
private JTextField display;
+
private JPanel buttonsPanel;
+
private JPanel numberButtonsPanel;
+
private JPanel cmdButtonsPanel;
+
private JButton numberButtons[];
+
private JButton cmdButtons[];
public static void main(String args[]) {
@@ -162,32 +169,36 @@
// get current value of display
curValue = Float.parseFloat(display.getText());
- if (cmd == null || cmd.equals("")) {
- // if no command was saved previously, save this one and clear
+ Operation currentOp = Operations.INSTANCE.getOperation(cmdName);
+ if ((currentOp instanceof BinaryOperation) && (cmd == null)) {
+ // if last clicked operation was binary and there is no saved
+ // operation, store it
cmd = cmdName;
clearDisplay = true;
} else {
- // perform the saved command
- Operation op = Operations.INSTANCE.getOperation(cmd);
- assert (op != null);
- if (op instanceof BinaryOperation) {
- BinaryOperation bop = (BinaryOperation) op;
+ // if saved command is binary perform it
+ Operation savedOp = Operations.INSTANCE.getOperation(cmd);
+ if (savedOp instanceof BinaryOperation) {
+ BinaryOperation bop = (BinaryOperation) savedOp;
newValue = bop.perform(value, curValue);
- } else if (op instanceof UnaryOperation) {
- UnaryOperation uop = (UnaryOperation) op;
+ } // if current operation is unary perform it
+ else if (currentOp instanceof UnaryOperation) {
+ UnaryOperation uop = (UnaryOperation) currentOp;
newValue = uop.perform(curValue);
}
- // display the result and order to clear
+ // display the result and prepare clear on next button
display.setText("" + newValue);
clearDisplay = true;
-
- if (cmdName.equals("=")) {
- // do not save = command
+ if (currentOp instanceof Equals) {
+ // do not save "=" command
cmd = null;
- } else {
- // save other commands
+ } else if (currentOp instanceof BinaryOperation) {
+ // save binary commands as they are executed on next operation
cmd = cmdName;
+ } else {
+ // clear saved command
+ cmd = null;
}
}
