org.apache.river.jeri.internal.runtime

Class Util

java.lang.Object

org.apache.river.jeri.internal.runtime.Util

public class Util
extends Object

Utility methods for implementing custom remote reference types.

Author:

Sun Microsystems, Inc.

Constructor Summary

Constructors

Constructor and Description
Util()

Method Summary

Modifier and Type	Method and Description
static void	checkPackageAccess(Class type) Check for permission to access the package of the specified class.
static void	checkProxyRemoteMethod(Class c, Method m) Throws IllegalArgumentException if any superinterface of c declares a method with the same name and parameter types as m that does not declare RemoteException or a superclass in its throws clause, or if any superinterface of c has its name in prohibitedProxyInterfaces.
static boolean	checkTrustEquivalence(Object subject, Object object) Returns true either if both arguments are null of if "subject" is an instance of TrustEquivalence and an invocation of TrustEquivalence.checkTrustEquivalence on "subject" with "object" as the argument returns true; returns false otherwise.
static void	clearStackTraces(Throwable t) Clear the stack trace of the given exception by replacing it with an empty StackTraceElement array, and do the same for all of its chained causative exceptions.
static boolean	equalInterfaces(Object obj1, Object obj2) Returns true if the interfaces implemented by obj1's class are the same (and in the same order) as obj2's class.
static boolean	equals(Object subject, Object object) Returns true either if both arguments are null or if an invocation of Object.equals on "subject" with "object" as the argument returns true; returns false otherwise;
static void	exceptionReceivedFromServer(Throwable t) Appends the current thread's stack trace to the stack trace of the given exception.
static InetAddress	getClientHost()
static String	getClientHostString()
static Subject	getClientSubject()
static long	getMethodHash(Method m) Returns the method hash for the method m.
static String	getMethodNameAndDescriptor(Method m) Returns a string consisting of the given method's name followed by its "method descriptor", as appropriate for use in the computation of the "method hash".
static Class[]	getRemoteInterfaces(Class remoteClass) Returns an array containing the remote interfaces implemented by the given class.
static String	getUnqualifiedName(Class c) Returns the binary name of the given type without package qualification.
static void	marshalValue(Class type, Object value, ObjectOutput out) Marshals value to an ObjectOutput stream, out, using RMI's serialization format for arguments or return values.
static void	populateContext(Collection context, boolean integrity, boolean atomic)
static void	populateContext(Collection context, InetAddress addr)
static void	populateContext(Collection context, Subject s)
static boolean	sameClassAndEquals(Object subject, Object object) Returns true either if both arguments are null or if both arguments refer to objects of the same class and an invocation of Object.equals on "subject" with "object" as the argument returns true; returns false otherwise.
static boolean	sameProxyClass(Object proxy1, Object proxy2) Returns true if proxy2 is a generated Proxy (proxy1 is assumed to be one) and the classes of both proxies implement the same ordered list of interfaces, and returns false otherwise.
static Object	unmarshalValue(Class type, ObjectInput in) Unmarshals a value of the specified type from the ObjectInput stream, in, using RMI's serialization format for arguments or return values and returns the result.

Methods inherited from class java.lang.Object

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

Constructor Detail

Util

public Util()

Method Detail

exceptionReceivedFromServer

public static void exceptionReceivedFromServer(Throwable t)

Appends the current thread's stack trace to the stack trace of the given exception. This method is used for exceptions that have been unmarshalled as the exceptional result of a remote method invocation, so that the client-side stack trace gets recorded in the exception (while preserving the server-side stack trace in the exception as well). Note that the (somewhat odd) names of this method and the method that this one internally delegates to are significant because these methods visually highlight the remote call boundary between the server-side and the client-side portions to readers of the combined stack trace.

clearStackTraces

public static void clearStackTraces(Throwable t)

Clear the stack trace of the given exception by replacing it with an empty StackTraceElement array, and do the same for all of its chained causative exceptions. This method is used when it is desired for the stack trace data of an exception to be suppressed before the exception gets marshalled to a remote virtual machine, perhaps for reasons of confidentiality or performance.

marshalValue

public static void marshalValue(Class type,
                                Object value,
                                ObjectOutput out)
                         throws IOException

Marshals value to an ObjectOutput stream, out, using RMI's serialization format for arguments or return values. For primitive types, the primitive type's class should be specified (i.e., for the type int, specify int.class), and the primitive value should be wrapped in instances of the appropriate wrapper class, such as java.lang.Integer or java.lang.Boolean.

Parameters:

type - Class object for the value to be marshalled

value - value to marshal

out - stream to which the value is marshalled

Throws:

IOException - if an I/O error occurs marshalling the value to the output stream

unmarshalValue

public static Object unmarshalValue(Class type,
                                    ObjectInput in)
                             throws IOException,
                                    ClassNotFoundException

Unmarshals a value of the specified type from the ObjectInput stream, in, using RMI's serialization format for arguments or return values and returns the result. For primitive types, the primitive type's class should be specified (i.e., for the primitive type int, specify int.class).

Parameters:

type - Class object for the value to be unmarshalled

in - stream from which the value is unmarshalled

Returns:

value unmarshalled from the input stream

Throws:

IOException - if an I/O error occurs marshalling the value to the output stream

ClassNotFoundException - if the type's class could not be found

getMethodHash

public static long getMethodHash(Method m)

Returns the method hash for the method m. Subsequent calls to getMethodHash passing the same method argument should be faster since this method caches internally the result of the method to method hash mapping. The method hash is calculated using the computeMethodHash method.

Parameters:

m - the remote method

Returns:

the method hash for the method m

getMethodNameAndDescriptor

public static String getMethodNameAndDescriptor(Method m)

Returns a string consisting of the given method's name followed by its "method descriptor", as appropriate for use in the computation of the "method hash". See section 4.3.3 of The Java(TM) Virtual Machine Specification for the definition of a "method descriptor".

getRemoteInterfaces

public static Class[] getRemoteInterfaces(Class remoteClass)

Returns an array containing the remote interfaces implemented by the given class.

Throws:

IllegalArgumentException - if remoteClass implements any illegal remote interfaces

NullPointerException - if remoteClass is null

checkProxyRemoteMethod

public static void checkProxyRemoteMethod(Class c,
                                          Method m)

Throws IllegalArgumentException if any superinterface of c declares a method with the same name and parameter types as m that does not declare RemoteException or a superclass in its throws clause, or if any superinterface of c has its name in prohibitedProxyInterfaces.

getUnqualifiedName

public static String getUnqualifiedName(Class c)

Returns the binary name of the given type without package qualification. Nested types are treated no differently from top-level types, so for a nested type, the returned name will still be qualified with the simple name of its enclosing top-level type (and perhaps other enclosing types), the separator will be '$', etc.

equals

public static boolean equals(Object subject,
                             Object object)

Returns true either if both arguments are null or if an invocation of Object.equals on "subject" with "object" as the argument returns true; returns false otherwise;

sameClassAndEquals

public static boolean sameClassAndEquals(Object subject,
                                         Object object)

Returns true either if both arguments are null or if both arguments refer to objects of the same class and an invocation of Object.equals on "subject" with "object" as the argument returns true; returns false otherwise. This method is used to compare to possibly-null references for object equality when neither object's class is trusted, with the restriction that only objects of the same class can be considered equal.

checkTrustEquivalence

public static boolean checkTrustEquivalence(Object subject,
                                            Object object)

Returns true either if both arguments are null of if "subject" is an instance of TrustEquivalence and an invocation of TrustEquivalence.checkTrustEquivalence on "subject" with "object" as the argument returns true; returns false otherwise.

sameProxyClass

public static boolean sameProxyClass(Object proxy1,
                                     Object proxy2)

Returns true if proxy2 is a generated Proxy (proxy1 is assumed to be one) and the classes of both proxies implement the same ordered list of interfaces, and returns false otherwise.

equalInterfaces

public static boolean equalInterfaces(Object obj1,
                                      Object obj2)

Returns true if the interfaces implemented by obj1's class are the same (and in the same order) as obj2's class.

populateContext

public static void populateContext(Collection context,
                                   InetAddress addr)

populateContext

public static void populateContext(Collection context,
                                   Subject s)

populateContext

public static void populateContext(Collection context,
                                   boolean integrity,
                                   boolean atomic)

getClientHost

public static InetAddress getClientHost()
                                 throws ServerNotActiveException

Throws:

ServerNotActiveException

getClientHostString

public static String getClientHostString()
                                  throws ServerNotActiveException

Throws:

ServerNotActiveException

getClientSubject

public static Subject getClientSubject()
                                throws ServerNotActiveException

Throws:

ServerNotActiveException

checkPackageAccess

public static void checkPackageAccess(Class type)

Check for permission to access the package of the specified class.

Throws:

SecurityException - if a security manager exists and invoking its checkPackageAccess method with the package name of the specified class throws a SecurityException