java.lang.Object
java.io.Reader
java.io.StringReader
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Readable
public class StringReader extends Reader
A character stream whose source is a string.
- Since:
- 1.1
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Field Summary
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Constructor Summary
Constructors Constructor Description StringReader(String s)
Creates a new string reader. -
Method Summary
Modifier and Type Method Description 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, which it does.int
read()
Reads a single character.int
read(char[] cbuf, int off, int len)
Reads characters into a portion of an array.boolean
ready()
Tells whether this stream is ready to be read.void
reset()
Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.long
skip(long ns)
Skips the specified number of characters in the stream.Methods declared in class java.io.Reader
nullReader, read, read, transferTo
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Constructor Details
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StringReader
Creates a new string reader.- Parameters:
s
- String providing the character stream.
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Method Details
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read
Reads a single character.- Overrides:
read
in classReader
- Returns:
- The character read, 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.- Specified by:
read
in classReader
- Parameters:
cbuf
- Destination bufferoff
- Offset at which to start writing 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:
IOException
- If an I/O error occursIndexOutOfBoundsException
- Ifoff
is negative, orlen
is negative, orlen
is greater thancbuf.length - off
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skip
Skips the specified number of characters in the stream. Returns the number of characters that were skipped.The
ns
parameter may be negative, even though theskip
method of theReader
superclass throws an exception in this case. Negative values ofns
cause the stream to skip backwards. Negative return values indicate a skip backwards. It is not possible to skip backwards past the beginning of the string.If the entire string has been read or skipped, then this method has no effect and always returns 0.
- Overrides:
skip
in classReader
- Parameters:
ns
- 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.- Overrides:
ready
in classReader
- Returns:
- True if the next read() is guaranteed not to block for input
- Throws:
IOException
- If the stream is closed
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markSupported
public boolean markSupported()Tells whether this stream supports the mark() operation, which it does.- Overrides:
markSupported
in 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:
mark
in 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 string, there is no actual limit, so this argument must not be negative, but is otherwise ignored.- Throws:
IllegalArgumentException
- IfreadAheadLimit < 0
IOException
- If an I/O error occurs
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reset
Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.- Overrides:
reset
in 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(), or reset() 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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