This is an abstract class that defines the methods common to all
CertPaths. Subclasses can handle different kinds of
certificates (X.509, PGP, etc.).
All CertPath objects have a type, a list of
Certificates, and one or more supported encodings. Because the
CertPath class is immutable, a CertPath cannot
change in any externally visible way after being constructed. This
stipulation applies to all public fields and methods of this class and any
added or overridden by subclasses.
The type is a String that identifies the type of
Certificates in the certification path. For each
certificate cert in a certification path certPath,
cert.getType().equals(certPath.getType()) must be
true.
The list of Certificates is an ordered List of
zero or more Certificates. This List and all
of the Certificates contained in it must be immutable.
Each CertPath object must support one or more encodings
so that the object can be translated into a byte array for storage or
transmission to other parties. Preferably, these encodings should be
well-documented standards (such as PKCS#7). One of the encodings supported
by a CertPath is considered the default encoding. This
encoding is used if no encoding is explicitly requested (for the
getEncoded()
method, for instance).
All CertPath objects are also Serializable.
CertPath objects are resolved into an alternate
CertPathRep
object during serialization. This allows
a CertPath object to be serialized into an equivalent
representation regardless of its underlying implementation.
CertPath objects can be created with a
CertificateFactory or they can be returned by other classes,
such as a CertPathBuilder.
By convention, X.509 CertPaths (consisting of
X509Certificates), are ordered starting with the target
certificate and ending with a certificate issued by the trust anchor. That
is, the issuer of one certificate is the subject of the following one. The
certificate representing the TrustAnchor
should not be
included in the certification path. Unvalidated X.509 CertPaths
may not follow these conventions. PKIX CertPathValidators will
detect any departure from these conventions that cause the certification
path to be invalid and throw a CertPathValidatorException.
Concurrent Access
All CertPath objects must be thread-safe. That is, multiple
threads may concurrently invoke the methods defined in this class on a
single CertPath object (or more than one) with no
ill effects. This is also true for the List returned by
CertPath.getCertificates.
Requiring CertPath objects to be immutable and thread-safe
allows them to be passed around to various pieces of code without worrying
about coordinating access. Providing this thread-safety is
generally not difficult, since the CertPath and
List objects in question are immutable.
CertPaths are equal if and only if their
types are equal and their certificate Lists (and by
implication the Certificates in those Lists)
are equal. A CertPath is never equal to an object that is
not a CertPath.
This algorithm is implemented by this method. If it is overridden, the behavior specified here must be maintained.
List returned must be immutable and thread-safe.Iterator via its remove method result in an
UnsupportedOperationException.Certificates in this certification
path. This is the same string that would be returned by
cert.getType()
for all Certificates in the certification path.
hashCode = path.getType().hashCode();
hashCode = 31*hashCode + path.getCertificates().hashCode();
path1.equals(path2) implies that
path1.hashCode()==path2.hashCode() for any two certification
paths, path1 and path2, as required by the
general contract of Object.hashCode.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.
toString method on each of the
Certificates in the path.
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.