* #### lock
protected [Object](../../java/lang/Object.html "class in java.lang") lock
The object used to synchronize operations on this stream. For efficiency, a character-stream object may use an object other than itself to protect critical sections. A subclass should therefore use the object in this field rather than `this` or a synchronized method.
Constructor Detail
* #### Reader
protected Reader()
Creates a new character-stream reader whose critical sections will synchronize on the reader itself.
* #### Reader
protected Reader([Object](../../java/lang/Object.html "class in java.lang") lock)
Creates a new character-stream reader whose critical sections will synchronize on the given object.
Parameters:
`lock` \- The Object to synchronize on.
Method Detail
* #### read
public int read([CharBuffer](../../java/nio/CharBuffer.html "class in java.nio") target)
throws [IOException](../../java/io/IOException.html "class in java.io")
Attempts to read characters into the specified character buffer. The buffer is used as a repository of characters as-is: the only changes made are the results of a put operation. No flipping or rewinding of the buffer is performed.
Specified by:
`[read](../../java/lang/Readable.html#read%28java.nio.CharBuffer%29)` in interface `[Readable](../../java/lang/Readable.html "interface in java.lang")`
Parameters:
`target` \- the buffer to read characters into
Returns:
The number of characters added to the buffer, or -1 if this source of characters is at its end
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if target is null
`[ReadOnlyBufferException](../../java/nio/ReadOnlyBufferException.html "class in java.nio")` \- if target is a read only buffer
Since:
1.5
* #### read
public int read()
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.
Subclasses that intend to support efficient single-character input should override this method.
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](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### read
public int read(char[] cbuf)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
Parameters:
`cbuf` \- Destination buffer
Returns:
The number of characters read, or -1 if the end of the stream has been reached
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### read
public abstract int read(char[] cbuf,
int off,
int len)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
Parameters:
`cbuf` \- Destination buffer
`off` \- Offset at which to start storing characters
`len` \- 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](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- If `off` is negative, or `len` is negative, or `len` is greater than `cbuf.length - off`
* #### skip
public long skip(long n)
throws [IOException](../../java/io/IOException.html "class in java.io")
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` \- The number of characters to skip
Returns:
The number of characters actually skipped
Throws:
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- If `n` is negative.
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### ready
public boolean ready()
throws [IOException](../../java/io/IOException.html "class in java.io")
Tells whether this stream is ready to be read.
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](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### markSupported
public boolean markSupported()
Tells whether this stream supports the mark() operation. The default implementation always returns false. Subclasses should override this method.
Returns:
true if and only if this stream supports the mark operation.
* #### mark
public void mark(int readAheadLimit)
throws [IOException](../../java/io/IOException.html "class in java.io")
Marks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.
Parameters:
`readAheadLimit` \- 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.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If the stream does not support mark(), or if some other I/O error occurs
* #### reset
public void reset()
throws [IOException](../../java/io/IOException.html "class in java.io")
Resets the stream. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If the stream has not been marked, or if the mark has been invalidated, or if the stream does not support reset(), or if some other I/O error occurs
* #### close
public abstract void close()
throws [IOException](../../java/io/IOException.html "class in java.io")
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.
Specified by:
`[close](../../java/lang/AutoCloseable.html#close%28%29)` in interface `[AutoCloseable](../../java/lang/AutoCloseable.html "interface in java.lang")`
Specified by:
`[close](../../java/io/Closeable.html#close%28%29)` in interface `[Closeable](../../java/io/Closeable.html "interface in java.io")`
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### transferTo
public long transferTo([Writer](../../java/io/Writer.html "class in java.io") out)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads all characters from this reader and writes the characters to the given writer in the order that they are read. On return, this reader will be at end of the stream. This method does not close either reader or writer.
This method may block indefinitely reading from the reader, or writing to the writer. The behavior for the case where the reader and/or writer is _asynchronously closed_, or the thread interrupted during the transfer, is highly reader and writer specific, and therefore not specified.
If an I/O error occurs reading from the reader or writing to the writer, then it may do so after some characters have been read or written. Consequently the reader may not be at end of the stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.
Parameters:
`out` \- the writer, non-null
Returns:
the number of characters transferred
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs when reading or writing
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `out` is `null`
Since:
10