Merge commit '42b2e5ca519766e37ce6941ba4faecc9691cc403' into upstream

[debian/openrocket] / core / src / de / congrace / exp4j / CustomFunction.java

diff --git a/core/src/de/congrace/exp4j/CustomFunction.java b/core/src/de/congrace/exp4j/CustomFunction.java
new file mode 100644 (file)
index 0000000..f49f948
--- /dev/null
+++ b/core/src/de/congrace/exp4j/CustomFunction.java
@@ -0,0 +1,90 @@
+package de.congrace.exp4j;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Stack;
+
+import de.congrace.exp4j.FunctionToken.Function;
+
+/**
+ * this classed is used to create custom functions for exp4j<br/>
+ * <br/>
+ * <b>Example</b><br/>
+ * <code><pre>{@code 
+ * CustomFunction fooFunc = new CustomFunction("foo") {
+ *             public double applyFunction(double value) {
+ *                     return value*Math.E;
+ *             }
+ * };
+ * double varX=12d;
+ * Calculable calc = new ExpressionBuilder("foo(x)").withCustomFunction(fooFunc).withVariable("x",varX).build();
+ * assertTrue(calc.calculate() == Math.E * varX);
+ * }</pre></code>
+ * 
+ * @author ruckus
+ * 
+ */
+public abstract class CustomFunction extends CalculationToken {
+    private int argc=1;
+
+       /**
+        * create a new single value input CustomFunction with a set name
+        * 
+        * @param value
+        *            the name of the function (e.g. foo)
+        */
+       protected CustomFunction(String value) throws InvalidCustomFunctionException{
+               super(value);
+               for (Function f:Function.values()) {
+                       if (value.equalsIgnoreCase(f.toString())){
+                               throw new InvalidCustomFunctionException(value + " is already reserved as a function name");
+                       }
+               }
+       }
+
+    /**
+     * create a new single value input CustomFunction with a set name
+     * 
+     * @param value
+     *            the name of the function (e.g. foo)
+     */
+    protected CustomFunction(String value,int argumentCount) throws InvalidCustomFunctionException{
+        super(value);
+        this.argc=argumentCount;
+        for (Function f:Function.values()) {
+            if (value.equalsIgnoreCase(f.toString())){
+                throw new InvalidCustomFunctionException(value + " is already reserved as a function name");
+            }
+        }
+    }
+
+    /**
+        * apply the function to a value
+        * 
+        * @param values
+        *            the values to which the function should be applied.
+        * @return the function value
+        */
+       public abstract Variable applyFunction(List<Variable> vars);
+
+    @Override
+       void mutateStackForCalculation(Stack<Variable> stack, VariableSet variables) {
+           List<Variable> args = new ArrayList<Variable>(argc);
+           for (int i=0; i < argc; i++) {
+               args.add(i, stack.pop() );
+           }
+           Collections.reverse(args); // Put elements in logical order
+           
+               stack.push(this.applyFunction(args));
+       }
+
+       @Override
+       void mutateStackForInfixTranslation(Stack<Token> operatorStack, StringBuilder output) {
+               operatorStack.push(this);
+       }
+       public int getArgumentCount() {
+           return argc;
+       }
+}