This class represents a "most-trusted CA", which is used as a trust anchor
for validating X.509 certification paths. A most-trusted CA includes the
public key of the CA, the CA's name, and any constraints upon the set of
paths which may be validated using this key. These parameters can be
specified in the form of a trusted X509Certificate or as
individual parameters.
Concurrent Access
All TrustAnchor objects must be immutable and
thread-safe. That is, multiple threads may concurrently invoke the
methods defined in this class on a single TrustAnchor
object (or more than one) with no ill effects. Requiring
TrustAnchor objects to be immutable and thread-safe
allows them to be passed around to various pieces of code without
worrying about coordinating access. This stipulation applies to all
public fields and methods of this class and any added or overridden
by subclasses.
TrustAnchor with the specified
X509Certificate and optional name constraints, which
are intended to be used as additional constraints when validating
an X.509 certification path.
The name constraints are specified as a byte array. This byte array should contain the DER encoded form of the name constraints, as they would appear in the NameConstraints structure defined in RFC 2459 and X.509. The ASN.1 definition of this structure appears below.
NameConstraints ::= SEQUENCE {
permittedSubtrees [0] GeneralSubtrees OPTIONAL,
excludedSubtrees [1] GeneralSubtrees OPTIONAL }
GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
GeneralSubtree ::= SEQUENCE {
base GeneralName,
minimum [0] BaseDistance DEFAULT 0,
maximum [1] BaseDistance OPTIONAL }
BaseDistance ::= INTEGER (0..MAX)
GeneralName ::= CHOICE {
otherName [0] OtherName,
rfc822Name [1] IA5String,
dNSName [2] IA5String,
x400Address [3] ORAddress,
directoryName [4] Name,
ediPartyName [5] EDIPartyName,
uniformResourceIdentifier [6] IA5String,
iPAddress [7] OCTET STRING,
registeredID [8] OBJECT IDENTIFIER}
Note that the name constraints byte array supplied is cloned to protect against subsequent modifications.
TrustAnchor where the
most-trusted CA is specified as an X500Principal and public key.
Name constraints are an optional parameter, and are intended to be used
as additional constraints when validating an X.509 certification path.
The name constraints are specified as a byte array. This byte array contains the DER encoded form of the name constraints, as they would appear in the NameConstraints structure defined in RFC 2459 and X.509. The ASN.1 notation for this structure is supplied in the documentation for TrustAnchor(X509Certificate trustedCert, byte[] nameConstraints) .
Note that the name constraints byte array supplied here is cloned to protect against subsequent modifications.
TrustAnchor where the
most-trusted CA is specified as a distinguished name and public key.
Name constraints are an optional parameter, and are intended to be used
as additional constraints when validating an X.509 certification path.
The name constraints are specified as a byte array. This byte array contains the DER encoded form of the name constraints, as they would appear in the NameConstraints structure defined in RFC 2459 and X.509. The ASN.1 notation for this structure is supplied in the documentation for TrustAnchor(X509Certificate trustedCert, byte[] nameConstraints) .
Note that the name constraints byte array supplied here is cloned to protect against subsequent modifications.
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
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.
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.
String
format.The name constraints are returned as a byte array. This byte array contains the DER encoded form of the name constraints, as they would appear in the NameConstraints structure defined in RFC 2459 and X.509. The ASN.1 notation for this structure is supplied in the documentation for TrustAnchor(X509Certificate trustedCert, byte[] nameConstraints) .
Note that the byte array returned is cloned to protect against subsequent modifications.
java.util.Hashtable.
The general contract of hashCode is:
hashCode method on each of
the two objects must produce the same integer result.
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 JavaTM programming language.)
wait methods.
The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.
This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:
synchronized statement
that synchronizes on the object.
Class, by executing a
synchronized static method of that class.
Only one thread at a time can own an object's monitor.
wait methods.
The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
TrustAnchor.
The current thread must own this object's monitor. The thread
releases ownership of this monitor and waits until another thread
notifies threads waiting on this object's monitor to wake up
either through a call to the notify method or the
notifyAll method. The thread then waits until it can
re-obtain ownership of the monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:
synchronized (obj) {
while (<condition does not hold>)
obj.wait();
... // Perform action appropriate to condition
}
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.The current thread must own this object's monitor.
This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:
A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:
synchronized (obj) {
while (<condition does not hold>)
obj.wait(timeout);
... // Perform action appropriate to condition
}
(For more information on this topic, see Section 3.2.3 in Doug Lea's
"Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
2000), or Item 50 in Joshua Bloch's "Effective Java Programming
Language Guide" (Addison-Wesley, 2001).
If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.
Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
This method is similar to the wait method of one
argument, but it allows finer control over the amount of time to
wait for a notification before giving up. The amount of real time,
measured in nanoseconds, is given by:
1000000*timeout+nanos
In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).
The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:
notify method
or the notifyAll method.
timeout
milliseconds plus nanos nanoseconds arguments, has
elapsed.
The thread then waits until it can re-obtain ownership of the monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:
synchronized (obj) {
while (<condition does not hold>)
obj.wait(timeout, nanos);
... // Perform action appropriate to condition
}
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.