BufferedInputStream
adds
functionality to another input stream-namely,
the ability to buffer the input and to
support the mark
and reset
methods. When the BufferedInputStream
is created, an internal buffer array is
created. As bytes from the stream are read
or skipped, the internal buffer is refilled
as necessary from the contained input stream,
many bytes at a time. The mark
operation remembers a point in the input
stream and the reset
operation
causes all the bytes read since the most
recent mark
operation to be
reread before new bytes are taken from
the contained input stream.
BufferedInputStream
and saves its argument, the input stream
in
, for later use. An internal
buffer array is created and stored in buf
.BufferedInputStream
with the specified buffer size,
and saves its argument, the input stream
in
, for later use. An internal
buffer array of length size
is created and stored in buf
.
The available
method of
BufferedInputStream
returns the sum of the number
of bytes remaining to be read in the buffer
(count - pos
)
and the result of calling the available
method of the
underlying input stream.
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.
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.)
mark
method of InputStream
.mark
and reset
methods. The markSupported
method of BufferedInputStream
returns
true
.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.
read
method of InputStream
.byte.length
bytes of data from this
input stream into an array of bytes. This method blocks until some
input is available.
This method simply performs the call
read(b, 0, b.length)
and returns
the result. It is important that it does
not do in.read(b)
instead;
certain subclasses of FilterInputStream
depend on the implementation strategy actually
used.
This method implements the general contract of the corresponding
read
method of
the InputStream
class. As an additional
convenience, it attempts to read as many bytes as possible by repeatedly
invoking the read
method of the underlying stream. This
iterated read
continues until one of the following
conditions becomes true:
read
method of the underlying stream returns
-1
, indicating end-of-file, or
available
method of the underlying stream
returns zero, indicating that further input requests would block.
read
on the underlying stream returns
-1
to indicate end-of-file then this method returns
-1
. Otherwise this method returns the number of bytes
actually read.
Subclasses of this class are encouraged, but not required, to attempt to read as many bytes as possible in the same fashion.
reset
method of InputStream
.
If markpos
is -1
(no mark has been set or the mark has been
invalidated), an IOException
is thrown. Otherwise, pos
is
set equal to markpos
.
skip
method of InputStream
.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())
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.