java.lang.Object
java.io.Reader
java.io.CharArrayReader
- All Implemented Interfaces:
Closeable,AutoCloseable,Readable
This class implements a character buffer that can be used as a
character-input stream.
- Since:
- 1.1
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected char[]The character buffer.protected intThe index of the end of this buffer.protected intThe position of mark in buffer.protected intThe current buffer position. -
Constructor Summary
ConstructorsConstructorDescriptionCharArrayReader(char[] buf) Creates a CharArrayReader from the specified array of chars.CharArrayReader(char[] buf, int offset, int length) Creates a CharArrayReader from the specified array of chars. -
Method Summary
Modifier and TypeMethodDescriptionvoidclose()Closes the stream and releases any system resources associated with it.voidmark(int readAheadLimit) Marks the present position in the stream.booleanTells whether this stream supports the mark() operation, which it does.intread()Reads a single character.intread(char[] cbuf, int off, int len) Reads characters into a portion of an array.booleanready()Tells whether this stream is ready to be read.voidreset()Resets the stream to the most recent mark, or to the beginning if it has never been marked.longskip(long n) Skips characters.Methods declared in class java.io.Reader
nullReader, read, read, transferTo
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Field Details
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buf
protected char[] bufThe character buffer. -
pos
protected int posThe current buffer position. -
markedPos
protected int markedPosThe position of mark in buffer. -
count
protected int countThe index of the end of this buffer. There is not valid data at or beyond this index.
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Constructor Details
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CharArrayReader
public CharArrayReader(char[] buf) Creates a CharArrayReader from the specified array of chars.- Parameters:
buf- Input buffer (not copied)
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CharArrayReader
public CharArrayReader(char[] buf, int offset, int length) Creates a CharArrayReader from the specified array of chars.The resulting reader will start reading at the given
offset. The total number ofcharvalues that can be read from this reader will be eitherlengthorbuf.length-offset, whichever is smaller.- Parameters:
buf- Input buffer (not copied)offset- Offset of the first char to readlength- Number of chars to read- Throws:
IllegalArgumentException- Ifoffsetis negative or greater thanbuf.length, or iflengthis negative, or if the sum of these two values is negative.
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Method Details
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read
Reads a single character.- Overrides:
readin classReader- Returns:
- The character read, as an integer in the range 0 to 65535
(
0x00-0xffff), or -1 if the end of the stream has been reached - Throws:
IOException- If an I/O error occurs
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read
Reads characters into a portion of an array.If
lenis zero, then no characters are read and0is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value-1is returned; otherwise, at least one character is read and stored intocbuf.- Specified by:
readin classReader- Parameters:
cbuf- Destination bufferoff- Offset at which to start storing characterslen- Maximum number of characters to read- Returns:
- The number of characters read, or -1 if the end of the stream has been reached
- Throws:
IndexOutOfBoundsException- Ifoffis negative, orlenis negative, orlenis greater thancbuf.length - offIOException- If an I/O error occurs
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skip
Skips characters. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.The
nparameter may be negative, even though theskipmethod of theReadersuperclass throws an exception in this case. Ifnis negative, then this method does nothing and returns0.- Overrides:
skipin classReader- Parameters:
n- The number of characters to skip- Returns:
- The number of characters actually skipped
- Throws:
IOException- If an I/O error occurs
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ready
Tells whether this stream is ready to be read. Character-array readers are always ready to be read.- Overrides:
readyin classReader- Returns:
- 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.
- Throws:
IOException- If an I/O error occurs
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markSupported
public boolean markSupported()Tells whether this stream supports the mark() operation, which it does.- Overrides:
markSupportedin classReader- Returns:
- true if and only if this stream supports the mark operation.
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mark
Marks the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.- Overrides:
markin classReader- Parameters:
readAheadLimit- Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a character array, there is no actual limit; hence this argument is ignored.- Throws:
IOException- If an I/O error occurs
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reset
Resets the stream to the most recent mark, or to the beginning if it has never been marked.- Overrides:
resetin classReader- Throws:
IOException- If an I/O error occurs
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close
public void close()Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.
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