Top Description Fields Constructors Methods
com.fasterxml.jackson.databind.type

public final Class ClassKey

extends Object
implements Comparable<ClassKey>, Serializable
Class Inheritance
All Implemented Interfaces
java.io.Serializable, java.lang.Comparable

Key class, used as an efficient and accurate key for locating per-class values, such as com.fasterxml.jackson.databind.JsonSerializers.

The reason for having a separate key class instead of directly using Class as key is mostly to allow for redefining hashCode method -- for some strange reason, Class does not redefine Object#hashCode and thus uses identity hash, which is pretty slow. This makes key access using Class unnecessarily slow.

Note

since class is not strictly immutable, caller must know what it is doing, if changing field values.

Field Summary

Modifier and TypeField and Description
private Class<?>
private String
private int
_hashCode

Let's cache hash code straight away, since we are almost certain to need it.

private static final long

Constructor Summary

AccessConstructor and Description
public
public
ClassKey(Class<?> clz)

Method Summary

Modifier and TypeMethod and Description
public int
compareTo(ClassKey
the object to be compared.
other
)

Implements java.lang.Comparable.compareTo.

Compares this object with the specified object for order.

public boolean
equals(Object
the reference object with which to compare.
o
)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public void
reset(Class<?> clz)

public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

_classback to summary
private Class<?> _class
_classNameback to summary
private String _className
_hashCodeback to summary
private int _hashCode

Let's cache hash code straight away, since we are almost certain to need it.

serialVersionUIDback to summary
private static final long serialVersionUID

Constructor Detail

ClassKeyback to summary
public ClassKey()
ClassKeyback to summary
public ClassKey(Class<?> clz)

Method Detail

compareToback to summary
public int compareTo(ClassKey other)

Implements java.lang.Comparable.compareTo.

Doc from java.lang.Comparable.compareTo.

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

The implementor must ensure signum(x.compareTo(y)) == -signum(y.compareTo(x)) for all x and y. (This implies that x.compareTo(y) must throw an exception if and only if y.compareTo(x) throws an exception.)

The implementor must also ensure that the relation is transitive: (x.compareTo(y) > 0 && y.compareTo(z) > 0) implies x.compareTo(z) > 0.

Finally, the implementor must ensure that x.compareTo(y)==0 implies that signum(x.compareTo(z)) == signum(y.compareTo(z)), for all z.

Parameters
other:ClassKey

the object to be compared.

Returns:int

a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Annotations
@Override
equalsback to summary
public boolean equals(Object o)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
o:Object

the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations
@Override
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object

Annotations
@Override
resetback to summary
public void reset(Class<?> clz)
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override