| java.lang.Object
 java.io.Reader
java.io.FilterReader
java.io.PushbackReader
| PushbackReader | | public class PushbackReader extends FilterReader (Code) | | PushbackReader is a filter class which allows chars read to be pushed back
into the stream so that they can be reread. Parsers may find this useful.
There is a progammable limit to the number of chars which may be pushed back.
If the buffer of pushed back chars is empty, chars are read from the source
reader.
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| Field Summary | |
| char[] | buf
The char array containing the chars to read. | | int | pos
The current position within the char array buf. |
| Method Summary | |
| public void | close()
Close this PushbackReader. | | public void | mark(int readAheadLimit)
Mark this PushbackReader. | | public boolean | markSupported()
Answers a boolean indicating whether or not this PushbackReader supports
mark() and reset(). | | public int | read()
Reads a single character from this PushbackReader and returns the result
as an int. | | public int | read(char[] buffer, int offset, int count)
Reads at most count chars from this PushbackReader and
stores them in char array buffer starting at
offset. | | public boolean | ready()
Answers a boolean indicating whether or not this
PushbackReader is ready to be read without blocking. | | public void | reset()
Resets this PushbackReader. | | public long | skip(long count)
Skips count number of characters in this Reader.
Subsequent read()'s will not return these characters
unless reset() is used.
Parameters:
count - the maximum number of characters to skip. | | public void | unread(char[] buffer)
Push back all the chars in buffer. | | public void | unread(char[] buffer, int offset, int count)
Push back count number of chars in buffer
starting at offset. | | public void | unread(int oneChar)
Push back one char. |
| buf | | char[] buf(Code) | | The char array containing the chars to read.
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| pos | | int pos(Code) | | The current position within the char array buf. A value
equal to buf.length indicates no chars available. A value of 0 indicates
the buffer is full.
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| PushbackReader | | public PushbackReader(Reader in)(Code) | | Constructs a new PushbackReader on the Reader in. The
size of the pushback buffer is set to the default, or 1 character.
Parameters:
in - the Reader to allow pushback operations on. |
| PushbackReader | | public PushbackReader(Reader in, int size)(Code) | | Constructs a new PushbackReader on the Reader in. The
size of the pushback buffer is set to size characters.
Parameters:
in - the Reader to allow pushback operations on.
Parameters:
size - the size of the pushback buffer (size>=0) incharacters.
throws:
IllegalArgumentException - if size <= 0 |
| close | | public void close() throws IOException(Code) | | Close this PushbackReader. This implementation closes this reader,
releases the buffer used to pushback characters, and closes the target
reader.
throws:
IOException - If an error occurs attempting to close this Reader. |
| mark | | public void mark(int readAheadLimit) throws IOException(Code) | | Mark this PushbackReader. Since mark is not supported, this method will
always throw IOException.
Parameters:
readAheadLimit - ignored, this method always throws IOException.
throws:
IOException - Since mark is not supported byt PushbackReader. |
| markSupported | | public boolean markSupported()(Code) | | Answers a boolean indicating whether or not this PushbackReader supports
mark() and reset(). This implementation always answers false since
PushbackReaders do not support mark/reset.
boolean indicates whether or not mark() and reset() aresupported. |
| read | | public int read() throws IOException(Code) | | Reads a single character from this PushbackReader and returns the result
as an int. The 2 lowest-order bytes are returned or -1 of the end of
stream was encountered. If the pushback buffer does not contain any
available chars then a char from the target input reader is returned.
int The char read or -1 if end of stream.
throws:
IOException - If an IOException occurs. |
| read | | public int read(char[] buffer, int offset, int count) throws IOException(Code) | | Reads at most count chars from this PushbackReader and
stores them in char array buffer starting at
offset. Answer the number of chars actually read or -1 if
no chars were read and end of stream was encountered. This implementation
reads chars from the pushback buffer first, then the target stream if
more chars are required to satisfy count.
Parameters:
buffer - the char array in which to store the read chars.
Parameters:
offset - the offset in buffer to store the read chars.
Parameters:
count - the maximum number of chars to store in buffer. the number of chars actually read or -1 if end of stream.
throws:
IOException - If an IOException occurs. |
| ready | | public boolean ready() throws IOException(Code) | | Answers a boolean indicating whether or not this
PushbackReader is ready to be read without blocking. If the result is
true, the next read() will not block. If
the result is false this Reader may or may not block when
read() is sent.
boolean true if the receiver will not block whenread() is called, false if unknownor blocking will occur.
throws:
IOException - If the Reader is already closed or some other IO erroroccurs. |
| reset | | public void reset() throws IOException(Code) | | Resets this PushbackReader. Since mark is not supported, always throw
IOException.
throws:
IOException - Since mark is not supported. |
| skip | | public long skip(long count) throws IOException(Code) | | Skips count number of characters in this Reader.
Subsequent read()'s will not return these characters
unless reset() is used.
Parameters:
count - the maximum number of characters to skip. the number of characters actually skipped.
throws:
IOException - If the Reader is already closed or some other IO erroroccurs.
throws:
IllegalArgumentException - If count is negative. |
| unread | | public void unread(char[] buffer) throws IOException(Code) | | Push back all the chars in buffer. The chars are pushed
so that they would be read back buffer[0], buffer[1], etc. If the push
back buffer cannot handle the entire contents of buffer,
an IOException will be thrown. Some of the buffer may already be in the
buffer after the exception is thrown.
Parameters:
buffer - the char array containing chars to push back into the reader.
throws:
IOException - If the pushback buffer becomes, or is, full. |
| unread | | public void unread(char[] buffer, int offset, int count) throws IOException(Code) | | Push back count number of chars in buffer
starting at offset. The chars are pushed so that they
would be read back buffer[offset], buffer[offset+1], etc. If the push
back buffer cannot handle the chars copied from buffer,
an IOException will be thrown. Some of the chars may already be in the
buffer after the exception is thrown.
Parameters:
buffer - the char array containing chars to push back into the reader.
Parameters:
offset - the location to start taking chars to push back.
Parameters:
count - the number of chars to push back.
throws:
IOException - If the pushback buffer becomes, or is, full. |
| unread | | public void unread(int oneChar) throws IOException(Code) | | Push back one char. Takes the char oneChar
and puts in in the local buffer of chars to read back before accessing
the target input stream.
Parameters:
oneChar - the char to push back into the stream.
throws:
IOException - If the pushback buffer is already full. |
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