Improve getBestCandidate() for BigDecimal args

- [DROOLS-5284] MVELTest.testTypeCoercionLongDivByInt fails with IBM JDK 8
lemonbashar · May 1, 2020 · d9d0a93 · d9d0a93
1 parent 71d422a
commit d9d0a93
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Showing 2 changed files with 52 additions and 2 deletions.
diff --git a/src/main/java/org/mvel2/util/ParseTools.java b/src/main/java/org/mvel2/util/ParseTools.java
@@ -265,7 +265,7 @@ public static Method getBestCandidate(Class[] arguments, String method, Class de
               bestScore = score;
             }
             else if (score == bestScore) {
-              if (isMoreSpecialized(meth, bestCandidate) && !isVarArgs) {
+              if ((isMoreSpecialized(meth, bestCandidate) || isMorePreciseForBigDecimal(meth, bestCandidate, arguments))&& !isVarArgs) {
                 bestCandidate = meth;
               }
             }
@@ -309,6 +309,39 @@ private static boolean isMoreSpecialized( Method newCandidate, Method oldCandida
            oldCandidate.getDeclaringClass().isAssignableFrom( newCandidate.getDeclaringClass());
   }
 
+  private static boolean isMorePreciseForBigDecimal(Method newCandidate, Method oldCandidate, Class[] arguments) {
+    Class<?>[] newParmTypes = newCandidate.getParameterTypes();
+    Class<?>[] oldParmTypes = oldCandidate.getParameterTypes();
+    int score = 0;
+    for (int i = 0; i != arguments.length; i++) {
+      Class<?> newParmType = newParmTypes[i];
+      Class<?> oldParmType = oldParmTypes[i];
+      if (arguments[i] != BigDecimal.class || !isNumeric(oldParmType) || !isNumeric(newParmType)) {
+        continue;
+      }
+      score += comparePrecision(unboxPrimitive(newParmType), unboxPrimitive(oldParmType));
+    }
+    return (score > 0);
+  }
+
+  private static int comparePrecision(Class<?> numeric1, Class<?> numeric2) {
+    if (numeric1 == numeric2) {
+      return 0;
+    }
+    if ((numeric1 == double.class) && (numeric2 == float.class || numeric2 == long.class || numeric2 == int.class || numeric2 == short.class)) {
+      return 1;
+    } else if ((numeric1 == float.class) && (numeric2 == long.class || numeric2 == int.class || numeric2 == short.class)) {
+      // float is preferred over long assuming users don't want to lose decimal part
+      return 1;
+    } else if ((numeric1 == long.class) && (numeric2 == int.class || numeric2 == short.class)) {
+      return 1;
+    } else if ((numeric1 == int.class) && numeric2 == short.class) {
+      return 1;
+    } else {
+      return -1;
+    }
+  }
+
   private static int getMethodScore(Class[] arguments, boolean requireExact, Class<?>[] parmTypes, boolean varArgs) {
     int score = 0;
     for (int i = 0; i != arguments.length; i++) {

diff --git a/src/test/java/org/mvel2/tests/core/CoreConfidenceTests.java b/src/test/java/org/mvel2/tests/core/CoreConfidenceTests.java
@@ -30,7 +30,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import junit.framework.TestCase;
-
+import org.junit.Assert;
 import org.mvel2.CompileException;
 import org.mvel2.DataConversion;
 import org.mvel2.MVEL;
@@ -4882,4 +4882,21 @@ public void testLiteralToStringWithSpace() throws Throwable {
       Serializable s = MVEL.compileExpression(expr);
       assertEquals(Integer.valueOf(hashCode), MVEL.executeExpression(s));
   }
+
+  public void testGetBestCandidateForBigDecimalArg() {
+    Class<?>[] arguments = new Class<?>[] {BigDecimal.class};
+    Method method = ParseTools.getBestCandidate(arguments, "round", Math.class, Math.class.getMethods(), true);
+    assertEquals(long.class, method.getReturnType());
+    Assert.assertArrayEquals(new Class<?>[] {double.class}, method.getParameterTypes());
+
+    arguments = new Class<?>[] {BigDecimal.class, BigDecimal.class};
+    method = ParseTools.getBestCandidate(arguments, "max", Math.class, Math.class.getMethods(), true);
+    assertEquals(double.class, method.getReturnType());
+    Assert.assertArrayEquals(new Class<?>[] {double.class, double.class}, method.getParameterTypes());
+
+    arguments = new Class<?>[] {BigDecimal.class, BigDecimal.class};
+    method = ParseTools.getBestCandidate(arguments, "scalb", Math.class, Math.class.getMethods(), true);
+    assertEquals(double.class, method.getReturnType());
+    Assert.assertArrayEquals(new Class<?>[] {double.class, int.class}, method.getParameterTypes());
+  }
 }