Class NonBlockingReader
- java.lang.Object
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- java.io.Reader
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- org.jline.utils.NonBlockingReader
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
,java.lang.Readable
- Direct Known Subclasses:
NonBlockingPumpReader
,NonBlockingReaderImpl
public abstract class NonBlockingReader extends java.io.Reader
A reader that provides non-blocking read operations.The NonBlockingReader class extends the standard Reader class to provide non-blocking read operations. Unlike standard readers, which block until data is available or the end of the stream is reached, non-blocking readers can be configured to return immediately or after a specified timeout if no data is available.
This class is particularly useful for terminal applications that need to perform other tasks while waiting for user input, or that need to implement features like input timeouts or polling.
The class defines two special return values:
EOF
(-1) - Indicates that the end of the stream has been reachedREAD_EXPIRED
(-2) - Indicates that the read operation timed out
Implementations of this class typically use a separate thread to handle blocking I/O operations, allowing the main thread to continue execution. The
shutdown()
method can be used to terminate this background thread when it is no longer needed.
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Field Summary
Fields Modifier and Type Field Description static int
EOF
static int
READ_EXPIRED
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Constructor Summary
Constructors Constructor Description NonBlockingReader()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description int
available()
int
peek(long timeout)
Peeks to see if there is a byte waiting in the input stream without actually consuming the byte.int
read()
int
read(char[] b, int off, int len)
This version of read() is very specific to jline's purposes, it will always always return a single byte at a time, rather than filling the entire buffer.int
read(long timeout)
Attempts to read a character from the input stream for a specific period of time.protected abstract int
read(long timeout, boolean isPeek)
Attempts to read a character from the input stream for a specific period of time.int
readBuffered(char[] b)
abstract int
readBuffered(char[] b, int off, int len, long timeout)
int
readBuffered(char[] b, long timeout)
void
shutdown()
Shuts down the thread that is handling blocking I/O.
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Field Detail
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EOF
public static final int EOF
- See Also:
- Constant Field Values
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READ_EXPIRED
public static final int READ_EXPIRED
- See Also:
- Constant Field Values
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Method Detail
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shutdown
public void shutdown()
Shuts down the thread that is handling blocking I/O.This method terminates the background thread that is used to handle blocking I/O operations. This allows the application to clean up resources and prevent thread leaks when the reader is no longer needed.
Note that if the thread is currently blocked waiting for I/O, it will not actually shut down until the I/O is received or the thread is interrupted. In some implementations, this method may interrupt the thread to force it to shut down immediately.
After calling this method, the reader should not be used anymore, as subsequent read operations may fail or block indefinitely.
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read
public int read() throws java.io.IOException
- Overrides:
read
in classjava.io.Reader
- Throws:
java.io.IOException
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peek
public int peek(long timeout) throws java.io.IOException
Peeks to see if there is a byte waiting in the input stream without actually consuming the byte.- Parameters:
timeout
- The amount of time to wait, 0 == forever- Returns:
- -1 on eof, -2 if the timeout expired with no available input or the character that was read (without consuming it).
- Throws:
java.io.IOException
- if anything wrong happens
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read
public int read(long timeout) throws java.io.IOException
Attempts to read a character from the input stream for a specific period of time.- Parameters:
timeout
- The amount of time to wait for the character- Returns:
- The character read, -1 if EOF is reached, or -2 if the read timed out.
- Throws:
java.io.IOException
- if anything wrong happens
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read
public int read(char[] b, int off, int len) throws java.io.IOException
This version of read() is very specific to jline's purposes, it will always always return a single byte at a time, rather than filling the entire buffer.- Specified by:
read
in classjava.io.Reader
- Parameters:
b
- the bufferoff
- the offset in the bufferlen
- the maximum number of chars to read- Throws:
java.io.IOException
- if anything wrong happens
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readBuffered
public int readBuffered(char[] b) throws java.io.IOException
- Throws:
java.io.IOException
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readBuffered
public int readBuffered(char[] b, long timeout) throws java.io.IOException
- Throws:
java.io.IOException
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readBuffered
public abstract int readBuffered(char[] b, int off, int len, long timeout) throws java.io.IOException
- Throws:
java.io.IOException
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available
public int available()
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read
protected abstract int read(long timeout, boolean isPeek) throws java.io.IOException
Attempts to read a character from the input stream for a specific period of time.- Parameters:
timeout
- The amount of time to wait for the characterisPeek
-true
if the character read must not be consumed- Returns:
- The character read, -1 if EOF is reached, or -2 if the read timed out.
- Throws:
java.io.IOException
- if anything wrong happens
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