DefaultRMIObjectWriteHandler

package saker.build.thirdparty.saker.rmi.io.writer

public final class DefaultRMIObjectWriteHandler implements RMIObjectWriteHandler

saker.build.thirdparty.saker.rmi.io.writer.DefaultRMIObjectWriteHandler

java.lang.Object

saker.build.thirdparty.saker.rmi.io.writer.RMIObjectWriteHandler

Writes the object using the default mechanism.

This write strategy is the default for transferring objects through an RMI connection.

After examining the object for non customizable aspects of the transferring (see RMIObjectWriteHandler documentation), the following rules apply to transferring objects:

In the following, the target type is the receiver type of the transferred object during transfer.
E.g. if the method is void method(Number n) and the parameter is an instance of Integer, then the target type is Number, and the object type is Integer.

If the target type is an array, then the object is transferred as an array, and its elements are transferred with a target type of the component type of the target type.
E.g. void method(Number[] n) with parameter Integer[], the elements will be transferred with target type of Number.
If the object is an array, then it will be transferred as an array, and its elements are transferred with a target type of the component type of the array type.
E.g. void method(Object n) with parameter Integer[], the elements will be transferred with target type of Integer.
If the object is an Enum instance, then it will be transferred by name. See EnumRMIObjectWriteHandler.
If the object is a ClassLoader instance, then it will be transferred by name using the specified classloader resolver settings.
If the object is a Class, Method, Constructor or Field instance, then it will be transferred by their enclosing reflectional information, and will be looked up on the other endpoint.
If the target type is an interface, or RemoteProxyObject then it will be written as a remote object. See RemoteRMIObjectWriteHandler.
E.g. void method(Runnable run) with parameter of a lambda () -> System.out.println("hello"), will be transferred as a remote object. Any calls on the received Runnable will result in printing "hello" to the stdout on the client side.
Regardless of target type, the object will be tried to be written as an Externalizable object. This will only happen if the given object is an instance of Externalizable.
The object is not written using ObjectOutputStream, but the RMIObjectOutput interface will be used to call Externalizable.writeExternal(ObjectOutput). Any ObjectOutput.writeObject(Object) calls will use the default object writing strategy, and Object target type.
If the object is an instace of Throwable, it will be attempted to be transferred as a serializable object. See SerializeRMIObjectWriteHandler. (Since saker.rmi 0.8.1)
As a fallback mechanism, the RMI runtime will write the given object as a remote to the other side. This means that if the actual target type can not accept an interface, then the RMI request will likely fail. This can be considered an undefined behavior and the user should attempt to properly choose the interfaces and instances for RMI use.
This fallback mechanism can be used as well to transfer Externalizable instances and some remote object with it.

Fields

public static final RMIObjectWriteHandler	INSTANCE Singleton instance of this class.

Constructors

public	DefaultRMIObjectWriteHandler() Creates a new instance.

Methods

public boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
public ObjectWriterKind	getKind() Gets the kind of this object write handler.
public int	hashCode() Returns a hash code value for the object.
public String	toString() Returns a string representation of the object.

Inherited methods
From: Object clone, finalize, getClass, notify, notifyAll, wait, wait, wait

public static final RMIObjectWriteHandler INSTANCE

Singleton instance of this class.

public DefaultRMIObjectWriteHandler()

Creates a new instance.

Use RMIObjectWriteHandler.defaultWriter() instead.

public boolean equals(Object obj)

Overridden from: Object

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.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

objthe reference object with which to compare.

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

Object.hashCode()

HashMap

public final ObjectWriterKind getKind()

Overridden from: RMIObjectWriteHandler

Gets the kind of this object write handler.

The kind.

public int hashCode()

Overridden from: Object

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by 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(Object) 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 Object.equals(Object) 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.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

a hash code value for this object.

Object.equals(Object)

System.identityHashCode(Object)

public String toString()

Overridden from: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())

a string representation of the object.