#1799 Fluent setters starting with set should work properly

processor/src/main/java/org/mapstruct/ap/spi/DefaultAccessorNamingStrategy.java

@@ -57,7 +57,8 @@ public class DefaultAccessorNamingStrategy implements AccessorNamingStrategy {
     }
 
     /**
-     * Returns {@code true} when the {@link ExecutableElement} is a getter method. A method is a getter when it starts
+     * Returns {@code true} when the {@link ExecutableElement} is a getter method. A method is a getter when it
+     * has no parameters, starts
      * with 'get' and the return type is any type other than {@code void}, OR the getter starts with 'is' and the type
      * returned is a primitive or the wrapper for {@code boolean}. NOTE: the latter does strictly not comply to the bean
      * convention. The remainder of the name is supposed to reflect the property name.
@@ -69,6 +70,10 @@ public class DefaultAccessorNamingStrategy implements AccessorNamingStrategy {
      * @return {@code true} when the method is a getter.
      */
     public boolean isGetterMethod(ExecutableElement method) {
+        if ( !method.getParameters().isEmpty() ) {
+            // If the method has parameters it can't be a getter
+            return false;
+        }
         String methodName = method.getSimpleName().toString();
 
         boolean isNonBooleanGetterName = methodName.startsWith( "get" ) && methodName.length() > 3 &&
@@ -166,11 +171,22 @@ public class DefaultAccessorNamingStrategy implements AccessorNamingStrategy {
     @Override
     public String getPropertyName(ExecutableElement getterOrSetterMethod) {
         String methodName = getterOrSetterMethod.getSimpleName().toString();
-        if ( methodName.startsWith( "get" ) || methodName.startsWith( "set" ) ) {
-            return IntrospectorUtils.decapitalize( methodName.substring( 3 ) );
-        }
-        else if ( isFluentSetter( getterOrSetterMethod ) ) {
-            return methodName;
+        if ( isFluentSetter( getterOrSetterMethod ) ) {
+            // If this is a fluent setter that starts with set and the 4th character is an uppercase one
+            // then we treat it as a Java Bean style method (we get the property starting from the 4th character).
+            // Otherwise we treat it as a fluent setter
+            // For example, for the following methods:
+            // * public Builder setSettlementDate(String settlementDate)
+            // * public Builder settlementDate(String settlementDate)
+            // We are going to extract the same property name settlementDate
+            if ( methodName.startsWith( "set" )
+                && methodName.length() > 3
+                && Character.isUpperCase( methodName.charAt( 3 ) ) ) {
+                return IntrospectorUtils.decapitalize( methodName.substring( 3 ) );
+            }
+            else {
+                return methodName;
+            }
         }
         return IntrospectorUtils.decapitalize( methodName.substring( methodName.startsWith( "is" ) ? 2 : 3 ) );
     }

processor/src/test/java/org/mapstruct/ap/test/bugs/_1799/Issue1799Mapper.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1799;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper
+public interface Issue1799Mapper {
+
+    Issue1799Mapper INSTANCE = Mappers.getMapper( Issue1799Mapper.class );
+
+    Target map(Source source);
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_1799/Issue1799Test.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1799;
+
+import java.util.Date;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Filip Hrisafov
+ */
+@WithClasses({
+    Issue1799Mapper.class,
+    Source.class,
+    Target.class,
+})
+@IssueKey("1799")
+@RunWith(AnnotationProcessorTestRunner.class)
+public class Issue1799Test {
+
+    @Test
+    public void fluentJavaBeanStyleSettersShouldWork() {
+        Target target = Issue1799Mapper.INSTANCE.map( new Source( new Date( 150 ), "Switzerland" ) );
+
+        assertThat( target.getSettlementDate() ).isEqualTo( new Date( 150 ) );
+        assertThat( target.getGetawayLocation() ).isEqualTo( "Switzerland" );
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_1799/Source.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1799;
+
+import java.util.Date;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class Source {
+
+    private final Date settlementDate;
+    private final String getawayLocation;
+
+    public Source(Date settlementDate, String getawayLocation) {
+        this.settlementDate = settlementDate;
+        this.getawayLocation = getawayLocation;
+    }
+
+    public Date getSettlementDate() {
+        return settlementDate;
+    }
+
+    public String getGetawayLocation() {
+        return getawayLocation;
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_1799/Target.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1799;
+
+import java.util.Date;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class Target {
+
+    private final Date settlementDate;
+    private final String getawayLocation;
+
+    public Target(Builder builder) {
+        this.settlementDate = builder.settlementDate;
+        this.getawayLocation = builder.getawayLocation;
+    }
+
+    public Date getSettlementDate() {
+        return settlementDate;
+    }
+
+    public String getGetawayLocation() {
+        return getawayLocation;
+    }
+
+    public static Target.Builder builder() {
+        return new Builder();
+    }
+
+    public static class Builder {
+
+        private Date settlementDate;
+        private String getawayLocation;
+
+        public Builder settlementDate(Date settlementDate) {
+            this.settlementDate = settlementDate;
+            return this;
+        }
+
+        public Builder getawayLocation(String getawayLocation) {
+            this.getawayLocation = getawayLocation;
+            return this;
+        }
+
+        public Target build() {
+            return new Target( this );
+        }
+    }
+}