uk.kludje

Class Meta<T>

java.lang.Object

uk.kludje.property.PropertyGetterList<T,Meta<T>>

uk.kludje.Meta<T>

Type Parameters:

T - the accessed type

public final class Meta<T>
extends PropertyGetterList<T,Meta<T>>

Provides a basic meta-method builder for common Object method implementations.

Example builds equals, hashCode and toString methods using the "id", "name" and "dateOfBirth" properties:

 import uk.kludje.Meta;
 import java.time.LocalDate;
 import static uk.kludje.Meta.meta;

 public class PersonPojo {
   private static final Meta<PersonPojo> META = meta(PersonPojo.class)
                              .longs(pp -> pp.id)
                              .objects(pp -> pp.name, pp -> pp.dateOfBirth);

   private final long id;
   private final String name;
   private final LocalDate dateOfBirth;

   public PersonPojo(long id, String name, LocalDate dateOfBirth) {
     this.id = id;
     this.name = name;
     this.dateOfBirth = dateOfBirth;
   }

   public String getName() {
     return name;
   }

   public LocalDate getDateOfBirth() {
     return dateOfBirth;
   }

   public boolean equals(Object obj) {
     return META.equals(this, obj);
   }

   public int hashCode() {
     return META.hashCode(this);
   }

   public String toString() {
     return META.toString(this);
   }
 }
 

Note: arrays are treated as objects by default; see MetaConfig.withShallowArraySupport(). If classes can be equal to subtypes use MetaConfig.withInstanceofEqualsTypeCheck().

Instances of this type are immutable and thread safe.

See Also:

PropertyGetterList

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Meta.BooleanGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.ByteGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.CharGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.DoubleGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.FloatGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.Getter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.IntGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.LongGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version
static interface	Meta.ShortGetter<T> Deprecated. this type will be deleted in favour of the uk.kludje.property version

Method Summary

Modifier and Type	Method and Description
Meta<T>	configure(MetaConfig config) Some aspects of the provided methods are caller-configurable.
boolean	equals(T t, java.lang.Object any) any is equal to t if it is of type T and all the properties defined by this type are equal.
int	hashCode(T t) Creates a hash of all values defined by the properties provided to this instance.
static <T> Meta<T>	meta() WARNING: when this method is used a subclass can never be equal to a parent type.
static <T> Meta<T>	meta(java.lang.Class<T> type)
java.lang.String	nameAt(int index)
protected Meta<T>	newInstance(Meta<T> old, java.lang.String name, TypedProperty getter)
TypedProperty	propertyAt(int index)
int	size()
java.lang.String	toString(T t) Creates a string form of the type for debugging purposes.

Methods inherited from class uk.kludje.property.PropertyGetterList

booleans, bytes, chars, doubles, floats, ints, longs, namedBoolean, namedByte, namedChar, namedDouble, namedFloat, namedInt, namedLong, namedObject, namedShort, objects, shorts

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

newInstance

protected Meta<T> newInstance(Meta<T> old,
                              java.lang.String name,
                              TypedProperty getter)

Specified by:

newInstance in class PropertyGetterList<T,Meta<T>>

meta

public static <T> Meta<T> meta(java.lang.Class<T> type)

Type Parameters:

T - the type

Parameters:

type - the class of type T

Returns:

a new instance with no properties

meta

public static <T> Meta<T> meta()

WARNING: when this method is used a subclass can never be equal to a parent type.

Type Parameters:

T - the type of class

Returns:

a new instance

configure

public Meta<T> configure(MetaConfig config)

Some aspects of the provided methods are caller-configurable. Use this method to alter these aspects of the configuration.

If meta() was used to instantiate the instance any changes to MetaConfig.ObjectEqualsPolicy will result in an error. Use meta(Class) instead.

Parameters:

config - the new configuration; must not be null

Returns:

a new instance with the new configuration

equals

public boolean equals(T t,
                      java.lang.Object any)

any is equal to t if it is of type T and all the properties defined by this type are equal.

Parameters:

t - a non-null instance of type T

any - any object, including null

Returns:

true if the arguments are equal

hashCode

public int hashCode(T t)

Creates a hash of all values defined by the properties provided to this instance. The hashing formula is not specified.

Parameters:

t - the non-null instance to create a hash for

Returns:

the hash

toString

public java.lang.String toString(T t)

Creates a string form of the type for debugging purposes. The exact form is not specified.

Parameters:

t - the non-null instance to create a string form of

Returns:

debug string

size

public int size()

Specified by:

size in class PropertyGetterList<T,Meta<T>>

Returns:

the number of properties this instance exposes

propertyAt

public TypedProperty propertyAt(int index)

Specified by:

propertyAt in class PropertyGetterList<T,Meta<T>>

Parameters:

index - the getter to return

Returns:

an object that can be cast to a getter type

See Also:

Getter, BooleanGetter, ByteGetter, ShortGetter, IntGetter, LongGetter, FloatGetter, DoubleGetter, CharGetter, PropertyType

nameAt

public java.lang.String nameAt(int index)

Specified by:

nameAt in class PropertyGetterList<T,Meta<T>>

Parameters:

index - the name index

Returns:

the property name for the given index or the empty string