ModelMapper can not mapping a method 'parent' named - mapping

Question

I'm tested on ModelMapper 0.7.5.
If a model have below conditions then ModelMapper can’t not mapping them.
a method name is ‘parent’ and return self class
a method name is ‘parentPath’ and return string
The test code is
public static class SomeModelMapper extends ModelMapper {
public void init() {
getConfiguration().setMatchingStrategy(MatchingStrategies.STANDARD);
}
}
#Data
public static class Dto1 {
private Dto1 another;
private String anothorPath;
}
#Data
public static class Dto2 {
private Dto2 parent;
private String parentPath;
}
#Test
public void testMapping() {
SomeModelMapper mapper = new SomeModelMapper();
mapper.init();
Map map = new HashMap<>();
map.put("anothorPath", "x");
Dto1 dto1 = mapper.map(map, Dto1.class);
assertThat(dto1.getAnothorPath(), is("x")); // success
map.clear();
map.put("parentPath", "y");
Dto2 dto2 = mapper.map(map, Dto2.class); // failed
assertThat(dto2.getParentPath(), is("y"));
}
error message is
org.modelmapper.MappingException: ModelMapper mapping errors:
1) Error mapping java.util.HashMap to com.semogyo.api.web.mapper.Object2ObjectMapperTest$Dto2
1 error
at org.modelmapper.internal.Errors.throwMappingExceptionIfErrorsExist(Errors.java:374)
at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:69)
at org.modelmapper.ModelMapper.mapInternal(ModelMapper.java:497)
at org.modelmapper.ModelMapper.map(ModelMapper.java:340)
at com.semogyo.api.web.mapper.Object2ObjectMapperTest.testMapping(Object2ObjectMapperTest.java:202)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:119)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: org.modelmapper.MappingException: ModelMapper mapping errors:
1) Failed to set value 'Object2ObjectMapperTest.Dto2(parent=null, parentPath=null)' on com.semogyo.api.web.mapper.Object2ObjectMapperTest$Dto2.setParentPath()
1 error
at org.modelmapper.internal.Errors.toMappingException(Errors.java:258)
at org.modelmapper.internal.PropertyInfoImpl$MethodMutator.setValue(PropertyInfoImpl.java:118)
at org.modelmapper.internal.MappingEngineImpl.setDestinationValue(MappingEngineImpl.java:249)
at org.modelmapper.internal.MappingEngineImpl.propertyMap(MappingEngineImpl.java:180)
at org.modelmapper.internal.MappingEngineImpl.typeMap(MappingEngineImpl.java:131)
at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:101)
at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:60)
... 30 more
Caused by: java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.modelmapper.internal.PropertyInfoImpl$MethodMutator.setValue(PropertyInfoImpl.java:116)
... 35 more
Why I can not use the "parent" of method name?

Answer 1

You can use "parent" as you like but not in this case. If you change your property name "parent" to other token it works (for example "father"). But try to change your other example Dto1 like this and look what happens:(property "anothor" to "another"):
#Data
public static class Dto1 {
private Dto1 another;
private String anotherPath;
}
And your HashMap (anothorPath -> anotherPath):
Map<String, String> map = new HashMap<>();
map.put("anotherPath", "x");
Dto1 dto1 = mapper.map(map, Dto1.class);
It happens the same error:
Caused by: org.modelmapper.MappingException: ModelMapper mapping errors:
1) Failed to set value 'Test.Dto1(another=null, anotherPath=null)' on com.example.Test$Dto1.setAnotherPath()
... same trace error
Why? Simply, as same as your sample it is generating a infinite loop.
ModelMapper maps String parentPath
ModelMapper maps DTO2 parent -> String ParentPath.
ModelMapper maps DTO2 parent -> DTO2 parent -> String parentPath
ModelMapper maps DTO2 parent -> DTO2 parent -> DTO2 parent -> String parentPath
....Infinite loop....This seems it will not stop...
Let me explain you why. ModelMapper looks String parentPath accessor and it is mappable, then it tries to map Dto2 parent and so on... If you put another name to Dto2 it doesn't try to map Dto2 and the loop will not be generated.
Examples
Case 1
Imagine your classes were like this:
#Data
public static class Dto1 {
private Dto2 another;
private String parentPath;
}
#Data
public static class Dto2 {
private Dto1 parent;
private String parentPath;
}
The output would be Test.Dto2(parent=Test.Dto1(another=null, parentPath=y), parentPath=y). It would map both String parentDto1 and Dto2.
Case 2
But in case your classes were like the next:
#Data
public static class Dto1 {
private Dto2 parent;
private String parentPath;
}
#Data
public static class Dto2 {
private Dto1 parent;
private String parentPath;
}
Again is generating the error, the same infinite loop.
Conclusion
This kind of mappings are not supported maybe the author thought that it would be better like this to be consistent, I don't know.