FileDocCategorySizeDatePackage
MarshalledObject.javaAPI DocJava SE 5 API9444Fri Aug 26 14:57:10 BST 2005java.rmi

MarshalledObject

public final class MarshalledObject extends Object implements Serializable
A MarshalledObject contains a byte stream with the serialized representation of an object given to its constructor. The get method returns a new copy of the original object, as deserialized from the contained byte stream. The contained object is serialized and deserialized with the same serialization semantics used for marshaling and unmarshaling parameters and return values of RMI calls: When the serialized form is created:
  • classes are annotated with a codebase URL from where the class can be loaded (if available), and
  • any remote object in the MarshalledObject is represented by a serialized instance of its stub.

When copy of the object is retrieved (via the get method), if the class is not available locally, it will be loaded from the appropriate location (specified the URL annotated with the class descriptor when the class was serialized.

MarshalledObject facilitates passing objects in RMI calls that are not automatically deserialized immediately by the remote peer.

version
1.33, 12/19/03
author
Ann Wollrath
author
Peter Jones
since
1.2

Fields Summary
private byte[]
objBytes
private byte[]
locBytes
private int
hash
private static final long
serialVersionUID
Indicate compatibility with 1.2 version of class.
Constructors Summary
public MarshalledObject(Object obj)
Creates a new MarshalledObject that contains the serialized representation of the current state of the supplied object. The object is serialized with the semantics used for marshaling parameters for RMI calls.

param
obj the object to be serialized (must be serializable)
exception
IOException if an IOException occurs; an IOException may occur if obj is not serializable.
since
1.2


                                                                   
      
	 
    
	if (obj == null) {
	    hash = 13;
	    return;
	}

	ByteArrayOutputStream bout = new ByteArrayOutputStream();
	ByteArrayOutputStream lout = new ByteArrayOutputStream();
	MarshalledObjectOutputStream out =
	    new MarshalledObjectOutputStream(bout, lout);
	out.writeObject(obj);
	out.flush();
	objBytes = bout.toByteArray();
	// locBytes is null if no annotations
	locBytes = (out.hadAnnotations() ? lout.toByteArray() : null);

	/*
	 * Calculate hash from the marshalled representation of object
	 * so the hashcode will be comparable when sent between VMs.
	 */
	int h = 0;
	for (int i = 0; i < objBytes.length; i++) {
	    h = 31 * h + objBytes[i];
	}
	hash = h;
    
Methods Summary
public booleanequals(java.lang.Object obj)
Compares this MarshalledObject to another object. Returns true if and only if the argument refers to a MarshalledObject that contains exactly the same serialized representation of an object as this one does. The comparison ignores any class codebase annotation, meaning that two objects are equivalent if they have the same serialized representation except for the codebase of each class in the serialized representation.

param
obj the object to compare with this MarshalledObject
return
true if the argument contains an equaivalent serialized object; false otherwise
since
1.2

	if (obj == this)
	    return true;

	if (obj != null && obj instanceof MarshalledObject) {
	    MarshalledObject other = (MarshalledObject) obj;

	    // if either is a ref to null, both must be
	    if (objBytes == null || other.objBytes == null)
		return objBytes == other.objBytes;

	    // quick, easy test
	    if (objBytes.length != other.objBytes.length)
		return false;

	    //!! There is talk about adding an array comparision method
	    //!! at 1.2 -- if so, this should be rewritten.  -arnold
	    for (int i = 0; i < objBytes.length; ++i) {
		if (objBytes[i] != other.objBytes[i])
		    return false;
	    }
	    return true;
	} else {
	    return false;
	}
    
public java.lang.Objectget()
Returns a new copy of the contained marshalledobject. The internal representation is deserialized with the semantics used for unmarshaling paramters for RMI calls.

return
a copy of the contained object
exception
IOException if an IOException occurs while deserializing the object from its internal representation.
exception
ClassNotFoundException if a ClassNotFoundException occurs while deserializing the object from its internal representation. could not be found
since
1.2

	if (objBytes == null)	// must have been a null object
	    return null;

	ByteArrayInputStream bin = new ByteArrayInputStream(objBytes);
	// locBytes is null if no annotations
	ByteArrayInputStream lin =
	    (locBytes == null ? null : new ByteArrayInputStream(locBytes));
	MarshalledObjectInputStream in =
	    new MarshalledObjectInputStream(bin, lin);
	Object obj = in.readObject();
	in.close();
	return obj;
    
public inthashCode()
Return a hash code for this MarshalledObject.

return
a hash code

	return hash;