map2pojo

Simple Java library for Map to POJO transformation 🧬

How to use. All you need is this to get the latest version:

<dependency>
  <groupId>com.github.javaslang.map2pojo</groupId>
  <artifactId>map2pojo</artifactId>
  <version>1.1.2</version>
</dependency>

Basic scenario

Transform a map to POJO:

POJO class:

public class SimplePojo {
    private String firstName;
    private BigDecimal height;
}

Transformation:

Map<String, Object> hashMap = new HashMap<String, Object>() {{
	put("FIRST_NAME", "John");
	put(" height_", "184.52");
}};
SimplePojo pojo = new Map2Pojo<>(SimplePojo.class).transform(hashMap);

Result:

SimplePojo(firstName=John, height=184.52)

Logic behind

Originally library supports string, number and date value types and conversion.

Map2Pojo<TestPojoClass> testMap2Pojo = new Map2Pojo<>(
		TestPojoClass.class,
		new DefaultNormalization(),
		new DefaultFillings()
);

TestPojoClass.class ‒ target POJO class

new DefaultNormalization() ‒ basic implementation of Function<String, String> for keys normalization providing the correlation between keys in the map and field names in the POJO.

new DefaultFillings() ‒ basic implementation of Fillings interface providing conversion of corresponding values from the original map to the POJO.

Annotations

@Map2Pojo.OrderedFields: provides the possibility for transformation basing on the order of keys / fields.

Retention: RUNTIME.

Target: TYPE.

Example:

POJO:

@Map2Pojo.OrderedFields
public static class OrderedTestPojo {
    private String firstField;
    private Date secondField;
    private BigDecimal thirdField;
}

Original map:

new HashMap<String, Object>() {{
    put("0", ...);
    put("1", ...);
    put("2", ...);
}};

---

@Map2Pojo.FormattedDate: provides the possibility of from / to date conversion basing on the specified format value.

Retention: RUNTIME.

Target: FIELD.

Example:

POJO:

...
@Map2Pojo.FormattedDate("dd-MM-yyyy")
private Date annotatedTestDate;
@Map2Pojo.FormattedDate("dd-MM-yyyy")
private String dateAsString;
...
@Map2Pojo.FormattedDate("dd-MM-yyyy")
private LocalDate annotatedTestLocalDate;
@Map2Pojo.FormattedDate("yyyy-MM-dd-HH.mm.ss")
private LocalDateTime annotatedTestLocalDateTime;
...

Original map:

new HashMap<String, Object>() {{
    ...
    put("Annotated Test Date", ...);
    put("DATE_AS_STRING", ...);
    ...
}};

---

@Map2Pojo.Locale: provides the possibility of number value conversion basing on the locale.

Retention: RUNTIME.

Target: TYPE, FIELD.

Example:

POJO:

...
@Map2Pojo.Locale("de")
private BigDecimal rate;
...

@Map2Pojo.Locale("de")
public static class TestPojo {
    ...
}

Original map:

new HashMap<String, Object>() {{
    ...
    put("RATE", "100,000000");
    ...
}});