Package java.io

Class BufferedWriter

java.lang.Object
java.io.Writer
java.io.BufferedWriter
All Implemented Interfaces:
Closeable, Flushable, Appendable, AutoCloseable
Direct Known Subclasses:
PemWriter
public class BufferedWriter
extends Writer
Wraps an existing Writer and buffers the output. Expensive interaction with the underlying reader is minimized, since most (smaller) requests can be satisfied by accessing the buffer alone. The drawback is that some extra space is required to hold the buffer and that copying takes place when filling that buffer, but this is usually outweighed by the performance benefits.

A typical application pattern for the class looks like this:

 BufferedWriter buf = new BufferedWriter(new FileWriter("file.java"));
See Also:
BufferedReader

  • Field Summary

    Fields inherited from class java.io.Writer

    lock

  • Constructor Summary

    Constructors
    Constructor Description
    BufferedWriter​(Writer out)
    Constructs a new BufferedWriter, providing out with a buffer of 8192 chars.
    BufferedWriter​(Writer out, int size)
    Constructs a new BufferedWriter, providing out with size chars of buffer.

  • Method Summary

    Modifier and Type Method Description
    void close()
    Closes this writer.
    void flush()
    Flushes this writer.
    void newLine()
    Writes a newline to this writer.
    void write​(char[] buffer, int offset, int count)
    Writes count characters starting at offset in buffer to this writer.
    void write​(int oneChar)
    Writes the character oneChar to this writer.
    void write​(String str, int offset, int count)
    Writes count characters starting at offset in str to this writer.

    Methods inherited from class java.io.Writer

    append, append, append, write, write

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • BufferedWriter

      public BufferedWriter​(Writer out)
      Constructs a new BufferedWriter, providing out with a buffer of 8192 chars.
      Parameters:
      out - the Writer the buffer writes to.

    • BufferedWriter

      public BufferedWriter​(Writer out, int size)
      Constructs a new BufferedWriter, providing out with size chars of buffer.
      Parameters:
      out - the OutputStream the buffer writes to.
      size - the size of buffer in chars.
      Throws:
      IllegalArgumentException - if size <= 0.

  • Method Details

    • close

      public void close() throws IOException
      Closes this writer. The contents of the buffer are flushed, the target writer is closed, and the buffer is released. Only the first invocation of close has any effect.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in class Writer
      Throws:
      IOException - if an error occurs while closing this writer.

    • flush

      public void flush() throws IOException
      Flushes this writer. The contents of the buffer are committed to the target writer and it is then flushed.
      Specified by:
      flush in interface Flushable
      Specified by:
      flush in class Writer
      Throws:
      IOException - if an error occurs while flushing this writer.

    • newLine

      public void newLine() throws IOException
      Writes a newline to this writer. On Android, this is "\n". The target writer may or may not be flushed when a newline is written.
      Throws:
      IOException - if an error occurs attempting to write to this writer.

    • write

      public void write​(char[] buffer, int offset, int count) throws IOException
      Writes count characters starting at offset in buffer to this writer. If count is greater than this writer's buffer, then the buffer is flushed and the characters are written directly to the target writer.
      Specified by:
      write in class Writer
      Parameters:
      buffer - the array containing characters to write.
      offset - the start position in buffer for retrieving characters.
      count - the maximum number of characters to write.
      Throws:
      IndexOutOfBoundsException - if offset < 0 or count < 0, or if offset + count is greater than the size of buffer.
      IOException - if this writer is closed or another I/O error occurs.

    • write

      public void write​(int oneChar) throws IOException
      Writes the character oneChar to this writer. If the buffer gets full by writing this character, this writer is flushed. Only the lower two bytes of the integer oneChar are written.
      Overrides:
      write in class Writer
      Parameters:
      oneChar - the character to write.
      Throws:
      IOException - if this writer is closed or another I/O error occurs.

    • write

      public void write​(String str, int offset, int count) throws IOException
      Writes count characters starting at offset in str to this writer. If count is greater than this writer's buffer, then this writer is flushed and the remaining characters are written directly to the target writer. If count is negative no characters are written to the buffer. This differs from the behavior of the superclass.
      Overrides:
      write in class Writer
      Parameters:
      str - the non-null String containing characters to write.
      offset - the start position in str for retrieving characters.
      count - maximum number of characters to write.
      Throws:
      IOException - if this writer has already been closed or another I/O error occurs.
      IndexOutOfBoundsException - if offset < 0 or offset + count is greater than the length of str.