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Chapter 11 The java.io Package |
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StringReader
Name
StringReaderSynopsis
- Class Name:
-
java.io.StringReader
- Superclass:
-
java.io.Reader
- Immediate Subclasses:
-
None
- Interfaces Implemented:
-
None
- Availability:
-
New as of JDK 1.1
Description
The StringReader class represents a character stream whose data source is a String. This class is similar to the CharArrayReader class, which uses a char array as its data source.
StringReader is meant to replace the StringBufferInputStream class as of JDK 1.1. Unlike StringBufferInputStream, StringReader handles Unicode characters and supports mark() and reset().
Class Summary
public class java.io.StringReader extends java.io.Reader {
// Constructors
public StringReader(String s);
// Instance Methods
public void close();
public void mark(int readAheadLimit);
public boolean markSupported();
public int read();
public int read(char[] cbuf, int off, int len);
public boolean ready();
public void reset();
public long skip(long ns);
}
Constructors
StringReader
public StringReader(String s)
- Parameters
-
- s
-
The String to use.
- s
- Description
-
This constructor creates a StringReader that uses the given String as its data source. The data is not copied, so changes made to the String affect the data that the StringReader returns.
Instance Methods
close
public void close()
- Overrides
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Reader.close()
- Description
-
This method closes the reader by removing the link between this StringReader and the String it was created with.
mark
public void mark(int readAheadLimit) throws IOException
- Parameters
-
- readAheadLimit
-
The maximum number of characters that can be read before the saved position becomes invalid.
- readAheadLimit
- Throws
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- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
-
Reader.mark()
- Description
-
This method causes the StringReader to remember its current position. A subsequent call to reset() causes the object to return to that saved position, and thus re-read a portion of the string. Because the data for this stream comes from a String, there is no limit on reading ahead, so readAheadLimit is ignored.
markSupported
public boolean markSupported()
- Returns
-
The boolean value true.
- Overrides
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Reader.markSupported()
- Description
-
This method returns true to indicate that this class supports mark() and reset().
read
public int read() throws IOException
- Returns
-
The next character or -1 if the end of the string is encountered.
- Throws
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- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
-
Reader.read()
- Description
-
This method returns the next character from the string. The method cannot block.
public int read(char[] cbuf, int off, int len) throws IOException
- Parameters
-
- cbuf
-
An array of characters to be filled from the stream.
- off
-
An offset into the character array.
- len
-
The number of characters to read.
- cbuf
- Returns
-
The actual number of characters read or -1 if the end of the string is encountered immediately.
- Throws
-
- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
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Reader.read(char[], int, int)
- Description
-
This method copies up to len characters from the internal buffer into the given array cbuf, starting at index off.
ready
public boolean ready() throws IOException
- Returns
-
A boolean value that indicates whether the stream is ready to be read.
- Throws
-
- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
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Reader.ready()
- Description
-
If there is any data left to be read from the string, this method returns true.
reset
public void reset() throws IOException
- Throws
-
- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
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Reader.reset()
- Description
-
This method resets the position of the StringReader to the position that was saved by calling the mark() method. If mark() has not been called, the StringReader is reset to read from the beginning of the string.
skip
public long skip(long ns) throws IOException
- Parameters
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- ns
-
The number of bytes to skip.
- ns
- Returns
-
The actual number of bytes skipped.
- Throws
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- IOException
-
If the stream is closed or any other kind of I/O error occurs.
- IOException
- Overrides
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Reader.skip()
- Description
-
This method skips ns characters of input. If you try to skip past the end of the string, the stream is positioned at the end of the string.
Inherited Methods
|
Method |
Inherited From |
Method |
Inherited From |
|---|---|---|---|
|
clone() |
Object |
equals (Object) |
Object |
|
finalize() |
Object |
getClass() |
Object |
|
hashCode() |
Object |
notify() |
Object |
|
notifyAll() |
Object |
read(char[]) |
Reader |
|
toString() |
Object |
wait() |
Object |
|
wait(long) |
Object |
wait(long, int) |
Object |
See Also
CharArrayReader, IOException, Reader, String, StringBufferInputStream
|
 |
|
| StringBufferInputStream |  |
StringWriter |
