# Class StringReader

java.lang.Object
java.io.Reader
java.io.StringReader

All Implemented Interfaces:
  `AutoCloseable`

public class StringReader extends Reader
A specialized `Reader` that reads characters from a `String` in a sequential manner.

See Also:
  - `StringWriter`

- ## Field Summary

  ### Fields inherited from class Reader

  `lock`
  Modifier and Type
  Field
  Description
  `protected Object`
  `lock`
  The object used to synchronize operations on this stream.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `StringReader(String str)`
  Construct a new `StringReader` with `str` as source.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `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.
  `int`
  `read()`
  Reads a single character from the source string and returns it as an integer with the two higher-order bytes set to 0.
  `int`
  `read(char[] buf, int offset, int len)`
  Reads at most `len` characters from the source string and stores them at `offset` in the character array `buf`.
  `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 ns)`
  Moves `ns` characters in the source string.

  ### Methods inherited from class Reader

  `read`
  Modifier and Type
  Method
  Description
  `int`
  `read(char[] cbuf)`
  Read characters into an array.

  ### Methods inherited from class Object

  `clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `final Class`
  `getClass()`
  Returns the runtime class of an object.
  `int`
  `hashCode()`
  Returns a hash code value for the object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `String`
  `toString()`
  Returns a string representation of the object.
  `final void`
  `wait()`
  Causes current thread to wait until another thread invokes the method or the method for this object.
  `final void`
  `wait(long timeout)`
  Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.
  `final void`
  `wait(long timeout, int nanos)`
  Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

- ## Constructor Details

  - ### StringReader

    public StringReader(String str)
    Construct a new `StringReader` with `str` as source. The size of the reader is set to the `length()` of the string and the Object to synchronize access through is set to `str`.
    Parameters:
      `str` - the source string for this reader.

- ## Method Details

  - ### close

    public void close()
    Closes this reader. Once it is closed, read operations on this reader will throw an `IOException`. Only the first invocation of this method has any effect.
    Specified by:
      `close` in interface `AutoCloseable`
    Specified by:
      `close` in class `Reader`

  - ### mark

    public void mark(int readLimit) throws IOException
    Sets a mark position in this reader. The parameter `readLimit` is ignored for this class. Calling `reset()` will reposition the reader back to the marked position.
    Overrides:
      `mark` in class `Reader`
    Parameters:
      `readLimit` - ignored for `StringReader` instances.
    Throws:
      `IllegalArgumentException` - if `readLimit < 0`.
      `IOException` - if this reader is closed.
    See Also:
      - `markSupported()`
      - `reset()`

  - ### markSupported

    public boolean markSupported()
    Indicates whether this reader supports the `mark()` and `reset()` methods. This implementation returns `true`.
    Overrides:
      `markSupported` in class `Reader`
    Returns:
      always `true`.

  - ### read

    public int read() throws IOException
    Reads a single character from the source string and returns it as an integer with the two higher-order bytes set to 0. Returns -1 if the end of the source string has been reached.
    Overrides:
      `read` in class `Reader`
    Returns:
      the character read or -1 if the end of the source string has been reached.
    Throws:
      `IOException` - if this reader is closed.

  - ### read

    public int read(char[] buf, int offset, int len) throws IOException
    Reads at most `len` characters from the source string and stores them at `offset` in the character array `buf`. Returns the number of characters actually read or -1 if the end of the source string has been reached.
    Specified by:
      `read` in class `Reader`
    Parameters:
      `buf` - the character array to store the characters read.
      `offset` - the initial position in `buffer` to store the characters read from this reader.
      `len` - the maximum number of characters to read.
    Returns:
      the number of characters read or -1 if the end of the reader has been reached.
    Throws:
      `IndexOutOfBoundsException` - if `offset < 0` or `len < 0`, or if `offset + len` is greater than the size of `buf`.
      `IOException` - if this reader is closed.

  - ### ready

    public boolean ready() throws IOException
    Indicates whether this reader is ready to be read without blocking. This implementation always returns `true`.
    Overrides:
      `ready` in class `Reader`
    Returns:
      always `true`.
    Throws:
      `IOException` - if this reader is closed.
    See Also:
      - `read()`
      - `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, it is reset to the beginning of the source string.
    Overrides:
      `reset` in class `Reader`
    Throws:
      `IOException` - if this reader is closed.
    See Also:
      - `mark(int)`
      - `markSupported()`

  - ### skip

    public long skip(long ns) throws IOException
    Moves `ns` characters in the source string. Unlike the `overridden method`, this method may skip negative skip distances: this rewinds the input so that characters may be read again. When the end of the source string has been reached, the input cannot be rewound.
    Overrides:
      `skip` in class `Reader`
    Parameters:
      `ns` - the maximum number of characters to skip. Positive values skip forward; negative values skip backward.
    Returns:
      the number of characters actually skipped. This is bounded below by the number of characters already read and above by the number of characters remaining:
      `-(num chars already read) <= distance skipped <= num chars remaining`.
    Throws:
      `IOException` - if this reader is closed.
    See Also:
      - `mark(int)`
      - `markSupported()`
      - `reset()`