PushbackReader
public
class
PushbackReader
extends FilterReader
A character-stream reader that allows characters to be pushed back into the
stream.
Summary
Public constructors |
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PushbackReader(Reader in, int size)
Creates a new pushback reader with a pushback buffer of the given size.
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PushbackReader(Reader in)
Creates a new pushback reader with a one-character pushback buffer.
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Public methods |
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void
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close()
Closes the stream and releases any system resources associated with
it.
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void
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mark(int readAheadLimit)
Marks the present position in the stream.
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boolean
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markSupported()
Tells whether this stream supports the mark() operation, which it does
not.
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int
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read()
Reads a single character.
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int
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read(char[] cbuf, int off, int len)
Reads characters into a portion of an array.
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boolean
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ready()
Tells whether this stream is ready to be read.
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void
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reset()
Resets the stream.
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long
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skip(long n)
Skips characters.
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void
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unread(char[] cbuf, int off, int len)
Pushes back a portion of an array of characters by copying it to the
front of the pushback buffer.
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void
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unread(char[] cbuf)
Pushes back an array of characters by copying it to the front of the
pushback buffer.
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void
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unread(int c)
Pushes back a single character by copying it to the front of the
pushback buffer.
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Inherited methods |
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 From
class
java.io.FilterReader
void
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close()
Closes the stream and releases any system resources associated with
it.
|
void
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mark(int readAheadLimit)
Marks the present position in the stream.
|
boolean
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markSupported()
Tells whether this stream supports the mark() operation.
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int
|
read()
Reads a single character.
|
int
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read(char[] cbuf, int off, int len)
Reads characters into a portion of an array.
|
boolean
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ready()
Tells whether this stream is ready to be read.
|
void
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reset()
Resets the stream.
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long
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skip(long n)
Skips characters.
|
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From
class
java.io.Reader
abstract
void
|
close()
Closes the stream and releases any system resources associated with
it.
|
void
|
mark(int readAheadLimit)
Marks the present position in the stream.
|
boolean
|
markSupported()
Tells whether this stream supports the mark() operation.
|
int
|
read()
Reads a single character.
|
abstract
int
|
read(char[] cbuf, int off, int len)
Reads characters into a portion of an array.
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int
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read(char[] cbuf)
Reads characters into an array.
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int
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read(CharBuffer target)
Attempts to read characters into the specified character buffer.
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boolean
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ready()
Tells whether this stream is ready to be read.
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void
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reset()
Resets the stream.
|
long
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skip(long n)
Skips characters.
|
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From
class
java.lang.Object
Object
|
clone()
Creates and returns a copy of this object.
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boolean
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equals(Object obj)
Indicates whether some other object is "equal to" this one.
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void
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finalize()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
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final
Class<?>
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getClass()
Returns the runtime class of this Object.
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int
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hashCode()
Returns a hash code value for the object.
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final
void
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notify()
Wakes up a single thread that is waiting on this object's
monitor.
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final
void
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notifyAll()
Wakes up all threads that are waiting on this object's monitor.
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String
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toString()
Returns a string representation of the object.
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final
void
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wait(long millis, int nanos)
Causes the current thread to wait until another thread invokes the
notify() method or the
notifyAll() method for this object, or
some other thread interrupts the current thread, or a certain
amount of real time has elapsed.
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final
void
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wait(long millis)
Causes the current thread to wait until either another thread invokes the
notify() method or the
notifyAll() method for this object, or a
specified amount of time has elapsed.
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final
void
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wait()
Causes the current thread to wait until another thread invokes the
notify() method or the
notifyAll() method for this object.
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From
interface
java.lang.Readable
abstract
int
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read(CharBuffer cb)
Attempts to read characters into the specified character buffer.
|
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From
interface
java.io.Closeable
abstract
void
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close()
Closes this stream and releases any system resources associated
with it.
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From
interface
java.lang.AutoCloseable
abstract
void
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close()
Closes this resource, relinquishing any underlying resources.
|
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Public constructors
PushbackReader
PushbackReader (Reader in,
int size)
Creates a new pushback reader with a pushback buffer of the given size.
| Parameters |
|---|
in |
Reader:
The reader from which characters will be read |
size |
int:
The size of the pushback buffer |
PushbackReader
PushbackReader (Reader in)
Creates a new pushback reader with a one-character pushback buffer.
| Parameters |
|---|
in |
Reader:
The reader from which characters will be read
|
Public methods
close
void close ()
Closes the stream and releases any system resources associated with
it. Once the stream has been closed, further read(),
unread(), ready(), or skip() invocations will throw an IOException.
Closing a previously closed stream has no effect.
mark
void mark (int readAheadLimit)
Marks the present position in the stream. The mark
for class PushbackReader always throws an exception.
| Parameters |
|---|
readAheadLimit |
int:
Limit on the number of characters that may be
read while still preserving the mark. After
reading this many characters, attempting to
reset the stream may fail. |
markSupported
boolean markSupported ()
Tells whether this stream supports the mark() operation, which it does
not.
| Returns |
|---|
boolean |
true if and only if this stream supports the mark operation.
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read
int read ()
Reads a single character.
| Returns |
|---|
int |
The character read, or -1 if the end of the stream has been
reached |
read
int read (char[] cbuf,
int off,
int len)
Reads characters into a portion of an array.
| Parameters |
|---|
cbuf |
char:
Destination buffer |
off |
int:
Offset at which to start writing characters |
len |
int:
Maximum number of characters to read |
| Returns |
|---|
int |
The number of characters read, or -1 if the end of the
stream has been reached |
ready
boolean ready ()
Tells whether this stream is ready to be read.
| Returns |
|---|
boolean |
True if the next read() is guaranteed not to block for input,
false otherwise. Note that returning false does not guarantee that the
next read will block. |
reset
void reset ()
Resets the stream. The reset method of
PushbackReader always throws an exception.
| Throws |
|---|
IOException |
Always, since reset is not supported
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skip
long skip (long n)
Skips characters. This method will block until some characters are
available, an I/O error occurs, or the end of the stream is reached.
| Parameters |
|---|
n |
long:
The number of characters to skip |
| Returns |
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long |
The number of characters actually skipped |
unread
void unread (char[] cbuf,
int off,
int len)
Pushes back a portion of an array of characters by copying it to the
front of the pushback buffer. After this method returns, the next
character to be read will have the value cbuf[off], the
character after that will have the value cbuf[off+1], and
so forth.
| Parameters |
|---|
cbuf |
char:
Character array |
off |
int:
Offset of first character to push back |
len |
int:
Number of characters to push back |
| Throws |
|---|
IOException |
If there is insufficient room in the pushback
buffer, or if some other I/O error occurs
|
unread
void unread (char[] cbuf)
Pushes back an array of characters by copying it to the front of the
pushback buffer. After this method returns, the next character to be
read will have the value cbuf[0], the character after that
will have the value cbuf[1], and so forth.
| Parameters |
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cbuf |
char:
Character array to push back |
| Throws |
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IOException |
If there is insufficient room in the pushback
buffer, or if some other I/O error occurs
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unread
void unread (int c)
Pushes back a single character by copying it to the front of the
pushback buffer. After this method returns, the next character to be read
will have the value (char)c.
| Parameters |
|---|
c |
int:
The int value representing a character to be pushed back |
| Throws |
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IOException |
If the pushback buffer is full,
or if some other I/O error occurs
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Developers