Pojo Analyzer
This library allows generation of a list that will contain getter, setter, and string name for each field of a POJO. This can be necessary for various use cases like iterating all fields of a POJO, manipulating fields of a POJO based on external properties and more. This library is different from other approaches to this problem in that it does the list generation at compile time, hence there is no performance issue.
Install
dependencies {
implementation("io.github.almogtavor:pojo-analyzers:1.3.0")
}Why
There is sometimes a need for accessing a field name in Java, as well as its value (e.g. getter) or its setter.
The most common need for this is to enable usage of configuration properties that define actions based on POJOs' fields.
These questions emphasize the general requirement (question 1, question 2).
Lombok does a great job providing @FieldNameConstants. But this is not enough, since @FieldNameConstants generates the name of the field, but not an acces to its getter nor setter. Therefore there is no way of interacting with the field after accessing its name.
Another requirement that gets solves by pojo-analyzer is the need for iteration of all POJO's fields. These questions emphasize this (question 1, question 2).
How does it work? Using @DetailedPojo
import io.github.almogtavor.pojo.analyzer.annotations.DetailedPojo;
import java.util.Date;
import lombok.AllArgsConstructor;
import lombok.Data;
@DetailedPojo
@AllArgsConstructor
@Data
public class TargetPojo {
private String entityId;
private Date createdDate;
private String text;
}Causes Pojo Analyzer to generate:
import io.github.almogtavor.pojo.analyzer.model.FieldDetails;
import javax.annotation.processing.Generated;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
@Generated("io.github.almogtavor.pojo.analyzer.processor.DetailedPojoAnnotationProcessor")
public class DetailedTargetPojo {
public static final Map<String, FieldDetails> map = new HashMap<String, FieldDetails>() {{
put("entityId", new FieldDetails<TargetPojo, String>("entityId", (TargetPojo t) -> t.getEntityId(), (TargetPojo t1, String t2) -> t1.setEntityId(t2)));
put("createdDate", new FieldDetails<TargetPojo, Date>("createdDate", (TargetPojo t) -> t.getCreatedDate(), (TargetPojo t1, Date t2) -> t1.setCreatedDate(t2)));
put("text", new FieldDetails<TargetPojo, String>("text", (TargetPojo t) -> t.getText(), (TargetPojo t1, String t2) -> t1.setText(t2)));
}};
}So we can use it as following:
TargetPojo targetPojo = new TargetPojo("123", new Date(), "pojo-analyzer");
FieldDetails<TargetPojo, String> entityIdField = DetailedTargetPojo.map.get("entityId");
entityIdField.getFieldValue(targetPojo); // "123"We can also specify:
import io.github.almogtavor.pojo.analyzer.model.VariableType;
@DetailedPojo(variableType = VariableType.LIST)
public class TargetPojo {
private String entityId;
private Date createdDate;
private String text;
}So we will get a generated list:
import io.github.almogtavor.pojo.analyzer.model.FieldDetails;
import javax.annotation.processing.Generated;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
@Generated("io.github.almogtavor.pojo.analyzer.processor.DetailedPojoAnnotationProcessor")
public class DetailedTargetPojo {
public static final List<FieldDetails> list = Arrays.asList(
new FieldDetails<TargetPojo, String>("entityId", (TargetPojo t) -> t.getEntityId(),
(TargetPojo t1, String t2) -> t1.seEntityId(t2)),
new FieldDetails<TargetPojo, Date>("createdDate", (TargetPojo t) -> t.getCreatedDate(),
(TargetPojo t1, Date t2) -> t1.setCreatedDate(t2)),
new FieldDetails<TargetPojo, String>("text", (TargetPojo t) -> t.getText(),
(TargetPojo t1, String t2) -> t1.setText(t2)));
}And now we can easily access the getter, setter and name of each field, since the FieldDetails class looks like this:
import lombok.Data;
@Data
public class FieldDetails<ClassTypeT, FieldTypeT> {
private String fieldName;
private Function<ClassTypeT, FieldTypeT> fieldGetter;
private BiConsumer<ClassTypeT, FieldTypeT> fieldSetter;
}We can also easily perform iteration over all fields of a class. For example:
class MyClass {
void iterateClasses() {
DetailedTargetPojo.list.stream().forEach(System.out::println);
}
}Requirements
The project has been compiled with JDK 1.8 for wider compatibility.
Limitations
Currently, there is no support in primitive types which will cause a runtime exception.
