Reader (moe.ios.core API)

java.lang.Object
- java.io.Reader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

Direct Known Subclasses:

BufferedReader, CharArrayReader, FilterReader, InputStreamReader, PipedReader, StringReader
```
public abstract class Reader
extends Object
implements Readable, Closeable
```
The base class for all readers. A reader is a means of reading data from a source in a character-wise manner. Some readers also support marking a position in the input and returning to this position later.
This abstract class does not provide a fully working implementation, so it needs to be subclassed, and at least the read(char[], int, int) and close() methods needs to be overridden. Overriding some of the non-abstract methods is also often advised, since it might result in higher efficiency.
Many specialized readers for purposes like reading from a file already exist in this package.

See Also:

Writer

Field Summary

Fields
Modifier and Type Field and Description

protected Object lock
The object used to synchronize access to the reader.

Fields
Modifier and Type	Field and Description
`protected Object`	`lock` The object used to synchronize access to the reader.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Reader()` Constructs a new `Reader` with `this` as the object used to synchronize critical sections.
`protected`	`Reader(Object lock)` Constructs a new `Reader` with `lock` used to synchronize critical sections.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract void`	`close()` Closes this reader.
`void`	`mark(int readLimit)` Sets a mark position in this reader.
`boolean`	`markSupported()` Indicates whether this reader supports the `mark()` and `reset()` methods.
`static Reader`	`nullReader()` Returns a new `Reader` that reads no characters.
`int`	`read()` Reads a single character from this reader and returns it as an integer with the two higher-order bytes set to 0.
`int`	`read(char[] buffer)` Reads characters from this reader and stores them in the character array `buffer` starting at offset 0.
`abstract int`	`read(char[] buffer, int offset, int count)` Reads up to `count` characters from this reader and stores them at `offset` in the character array `buffer`.
`int`	`read(CharBuffer target)` Reads characters and puts them into the `target` character buffer.
`boolean`	`ready()` Indicates whether this reader is ready to be read without blocking.
`void`	`reset()` Resets this reader's position to the last `mark()` location.
`long`	`skip(long charCount)` Skips `charCount` characters in this reader.
`long`	`transferTo(Writer out)` Reads all characters from this reader and writes the characters to the given writer in the order that they are read.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - lock
```
protected Object lock
```
    The object used to synchronize access to the reader.
- Constructor Detail
  - Reader
```
protected Reader()
```
    Constructs a new Reader with this as the object used to synchronize critical sections.
  - Reader
```
protected Reader(Object lock)
```
    Constructs a new Reader with lock used to synchronize critical sections.
    
    Parameters:
    
    lock - the Object used to synchronize critical sections.
    
    Throws:
    
    NullPointerException - if lock is null.
- Method Detail
  - nullReader
```
public static Reader nullReader()
```
    Returns a new Reader that reads no characters. The returned stream is initially open. The stream is closed by calling the close() method. Subsequent calls to close() have no effect.
    While the stream is open, the read(), read(char[]), read(char[], int, int), read(Charbuffer), ready(), skip(long), and transferTo() methods all behave as if end of stream has been reached. After the stream has been closed, these methods all throw IOException.
    The markSupported() method returns false. The mark() and reset() methods throw an IOException.
    The object used to synchronize operations on the returned Reader is not specified.
    
    Returns:
    
    a Reader which reads no characters
    
    Since:
    
    11
  - close
```
public abstract void close()
                    throws IOException
```
    Closes this reader. Implementations of this method should free any resources associated with the reader.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Throws:
    
    IOException - if an error occurs while closing this reader.
  - mark
```
public void mark(int readLimit)
          throws IOException
```
    Sets a mark position in this reader. The parameter readLimit indicates how many characters can be read before the mark is invalidated. Calling reset() will reposition the reader back to the marked position if readLimit has not been surpassed.
    This default implementation simply throws an IOException; subclasses must provide their own implementation.
    
    Parameters:
    
    readLimit - the number of characters that can be read before the mark is invalidated.
    
    Throws:
    
    IllegalArgumentException - if readLimit < 0.
    
    IOException - if an error occurs while setting a mark in this reader.
    
    See Also:
    
    markSupported(), reset()
  - markSupported
```
public boolean markSupported()
```
    Indicates whether this reader supports the mark() and reset() methods. This default implementation returns false.
    
    Returns:
    
    always false.
  - read
```
public int read()
         throws IOException
```
    Reads a single character from this reader and returns it as an integer with the two higher-order bytes set to 0. Returns -1 if the end of the reader has been reached.
    
    Returns:
    
    the character read or -1 if the end of the reader has been reached.
    
    Throws:
    
    IOException - if this reader is closed or some other I/O error occurs.
  - read
```
public int read(char[] buffer)
         throws IOException
```
    Reads characters from this reader and stores them in the character array buffer starting at offset 0. Returns the number of characters actually read or -1 if the end of the reader has been reached.
    
    Throws:
    
    IOException - if this reader is closed or some other I/O error occurs.
  - read
```
public abstract int read(char[] buffer,
                         int offset,
                         int count)
                  throws IOException
```
    Reads up to count characters from this reader and stores them at offset in the character array buffer. Returns the number of characters actually read or -1 if the end of the reader has been reached.
    
    Throws:
    
    IOException - if this reader is closed or some other I/O error occurs.
  - ready
```
public boolean ready()
              throws IOException
```
    Indicates whether this reader is ready to be read without blocking. Returns true if this reader will not block when read is called, false if unknown or blocking will occur. This default implementation always returns false.
    
    Returns:
    
    always false.
    
    Throws:
    
    IOException - if this reader is closed or some other I/O error occurs.
    
    See Also:
    
    read(), read(char[]), read(char[], int, int)
  - reset
```
public void reset()
           throws IOException
```
    Resets this reader's position to the last mark() location. Invocations of read() and skip() will occur from this new location. If this reader has not been marked, the behavior of reset() is implementation specific. This default implementation throws an IOException.
    
    Throws:
    
    IOException - always thrown in this default implementation.
    
    See Also:
    
    mark(int), markSupported()
  - skip
```
public long skip(long charCount)
          throws IOException
```
    Skips charCount characters in this reader. Subsequent calls of read methods will not return these characters unless reset is used. This method may perform multiple reads to read charCount characters.
    
    Returns:
    
    the number of characters actually skipped.
    
    Throws:
    
    IllegalArgumentException - if charCount < 0.
    
    IOException - if this reader is closed or some other I/O error occurs.
    
    See Also:
    
    mark(int), markSupported(), reset()
  - read
```
public int read(CharBuffer target)
         throws IOException
```
    Reads characters and puts them into the target character buffer.
    
    Specified by:
    
    read in interface Readable
    
    Parameters:
    
    target - the destination character buffer.
    
    Returns:
    
    the number of characters put into target or -1 if the end of this reader has been reached before a character has been read.
    
    Throws:
    
    IOException - if any I/O error occurs while reading from this reader.
    
    NullPointerException - if target is null.
    
    ReadOnlyBufferException - if target is read-only.
  - transferTo
```
public long transferTo(Writer out)
                throws IOException
```
    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 - if an I/O error occurs when reading or writing
    
    NullPointerException - if out is null
    
    Since:
    
    10

Class Reader

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

lock

Constructor Detail

Reader

Reader

Method Detail

nullReader

close

mark

markSupported

read

read

read

ready

reset

skip

read

transferTo