garc33 / metatype

metatype

MetaType is APT processor that generate "Meta Classes" from your beans. It provide a simple way to do bean reflection with some improvments :

• Check at compile time
• Driect access to getters/setters
• Utils for some common algorithms
• Chained accessors

How to use it ?

With maven: Add repository (the artifact is currently hosted in github repo)

<repository>
  <id>garc33-releases</id>
  <url>https://raw.github.com/garc33/m2p2-repository/mvn-repo/maven/releases/</url>
</repository>

Add dependency

<dependency>
  <groupId>fr.herman</groupId>
  <artifactId>metatype</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>

Configure APT plugin

<plugin>
  <groupId>com.mysema.maven</groupId>
  <artifactId>apt-maven-plugin</artifactId>
  <version>1.1.0</version>
  <executions>
    <execution>
      <id>metatype</id>
      <goals>
        <goal>process</goal>
      </goals>
      <configuration>
        <outputDirectory>${project.build.directory}/generated-sources</outputDirectory>
        <processor>fr.herman.metatype.processor.MetaTypeProcessor</processor>
      </configuration>
    </execution>
  </executions>
</plugin>

Put @MetaBean annotation on your class (or interface)

@MetaBean
public static class Person
{
	private String firstName, lastName;
	private Address address;

	public String getFirstName(){
		return firstName;
	}
	public void setFirstName(String firstName){
		this.firstName = firstName;
	}
	public String getLastName(){
		return lastName;
	}
	public void setLastName(String lastName){
		this.lastName = lastName;
	}
	//customize property
	@MetaGetter("initials")
	public String initialsWithPointBetween(){
		return firstName.substring(0, 1) + '.' + lastName.substring(0, 1);
	}
	public Address getAddress()
	{
		return address;
	}
	public void setAddress(Address address)
	{
		this.address = address;
	}
}

@MetaBean
public static class Child extends Person{
	private final String suffix="Jr";

	public String getSuffix(){
		return suffix;
	}
	@Override
	public String initialsWithPointBetween(){
		return getFirstName().substring(0, 1)+
			'.'+suffix.substring(0, 1) + '.' +
				getLastName().substring(0, 1);
	}
}

@MetaBean
public static class Address{
	private String street,city;

	public String getStreet(){
		return street;
	}

	public void setStreet(String street){
		this.street = street;
	}

	public String getCity(){
		return city;
	}

	public void setCity(String city){
		this.city = city;
	}
}

PersonMeta and ChildMeta class will be generated ! You can use them like this :

Person woman = new Person();
woman.setFirstName("Jane");

// value defaulting inline
Metas.defaultValue(PersonMeta.$.firstName, woman, "John");
assertEquals(woman.getFirstName(), "Jane");
Metas.defaultValue(PersonMeta.$.lastName, woman, "Doe");
assertEquals(woman.getLastName(), "Doe");

// Bean to map
Map<String, ?> map = Metas.toMap(woman, PersonMeta.$.firstName,PersonMeta.$.lastName);
assertEquals(map.get("firstName"), "Jane");
assertEquals(map.get(PersonMeta.$.lastName.name()), "Doe");

//Customized property
assertEquals(woman.initialsWithPointBetween(), "J.D");
assertEquals(PersonMeta.$.initials.getValue(woman), "J.D");

Person man = new Person();
man.setFirstName("John");
man.setLastName("Smith");

//Copy property from an bean to anther
Metas.copyValue(man, woman, PersonMeta.$.lastName);
assertEquals(woman.getFirstName(), "Jane");
assertEquals(woman.getLastName(), "Smith");

//Copy values and handle inheritance
Child child = new Child();
Metas.copyValues(man, child, PersonMeta.$.firstName,PersonMeta.$.lastName);
assertEquals(child.getFirstName(), "John");
assertEquals(child.getLastName(), "Smith");

List<Person> familly = asList(woman,man,child);

//Collect
Collection<String> initials = Metas.collect(familly,  PersonMeta.$.initials);
assertEquals(initials, new ArrayList<>(asList("J.S","J.S","J.J.S")));

//Distinct
assertEquals(Metas.distinct(familly, PersonMeta.$.initials).size(), 2);

//Frequency
Map<String, Integer> frequency = Metas.frequency(familly, PersonMeta.$.firstName);
assertEquals(frequency.get("John").intValue(), 2);
assertEquals(frequency.get("Jane").intValue(), 1);

Address address = new Address();
address.setCity("Paris");

//Batch set
Metas.apply(PersonMeta.$.address, familly, address);
Metas.apply(PersonMeta.$.address.street, familly, asList("Provence","La Fayette","Victoire"));

//Fluent
assertEquals(PersonMeta.$.address.city.getValue(man),"Paris");