Document MethodRef overload signatures in the sample library model #1016

sample-library-model/src/main/java/com/uber/modelexample/ExampleLibraryModels.java

@@ -40,10 +40,18 @@ public ImmutableSetMultimap<MethodRef, Integer> nonNullParameters() {
     return ImmutableSetMultimap.of();
   }
 
+  /**
+   * MethodRef signatures are the method name plus argument types with no spaces after commas.
+   * Overloads need a separate entry each; {@code isEmptyOrNull(java.lang.CharSequence, boolean)}
+   * (space after the comma) would not match the two-argument method.
+   */
   @Override
   public ImmutableSetMultimap<MethodRef, Integer> nullImpliesTrueParameters() {
     return ImmutableSetMultimap.<MethodRef, Integer>builder()
         .put(methodRef("org.utilities.StringUtils", "isEmptyOrNull(java.lang.CharSequence)"), 0)
+        .put(
+            methodRef("org.utilities.StringUtils", "isEmptyOrNull(java.lang.CharSequence,boolean)"),
+            0)
         .build();
   }
 

sample/src/main/java/com/uber/mylib/MyClass.java

@@ -20,6 +20,13 @@ static int checkModel(@Nullable String s) {
     return 0;
   }
 
+  static int checkModelTrim(@Nullable String s) {
+    if (!StringUtils.isEmptyOrNull(s, true)) {
+      return s.hashCode();
+    }
+    return 0;
+  }
+
   static void foo() {
     log(null);
   }

sample/src/main/java/org/utilities/StringUtils.java

@@ -7,4 +7,11 @@ public class StringUtils {
   public static boolean isEmptyOrNull(@Nullable CharSequence value) {
     return value == null || value.length() == 0;
   }
+
+  public static boolean isEmptyOrNull(@Nullable CharSequence value, boolean trim) {
+    if (value == null) {
+      return true;
+    }
+    return trim ? value.toString().trim().isEmpty() : value.length() == 0;
+  }
 }