Class StringWriter

  • All Implemented Interfaces:
    Closeable, Flushable, Appendable, AutoCloseable


    public class StringWriter
    extends Writer
    A character stream that collects its output in a string buffer, which can then be used to construct a string.

    Closing a StringWriter has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

    Since:
    JDK1.1
    • Field Summary

    • Constructor Summary

      Constructors

      Constructor and Description
      StringWriter()
      Create a new string writer using the default initial string-buffer size.
      StringWriter(int initialSize)
      Create a new string writer using the specified initial string-buffer size.
    • Constructor Detail

      • StringWriter

        public StringWriter()
        Create a new string writer using the default initial string-buffer size.
      • StringWriter

        public StringWriter(int initialSize)
        Create a new string writer using the specified initial string-buffer size.
        Parameters:
        initialSize - The number of char values that will fit into this buffer before it is automatically expanded
        Throws:
        IllegalArgumentException - If initialSize is negative
    • Method Detail

      • write

        public void write(int c)
        Write a single character.
        Overrides:
        write in class  Writer
        Parameters:
        c - int specifying a character to be written
      • write

        public void write(char[] cbuf,
                          int off,
                          int len)
        Write a portion of an array of characters.
        Specified by:
        write in class  Writer
        Parameters:
        cbuf - Array of characters
        off - Offset from which to start writing characters
        len - Number of characters to write
      • write

        public void write(String str)
        Write a string.
        Overrides:
        write in class  Writer
        Parameters:
        str - String to be written
      • write

        public void write(String str,
                          int off,
                          int len)
        Write a portion of a string.
        Overrides:
        write in class  Writer
        Parameters:
        str - String to be written
        off - Offset from which to start writing characters
        len - Number of characters to write
      • append

        public StringWriter append(CharSequence csq)
        Appends the specified character sequence to this writer.

        An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation

             out.write(csq.toString()) 

        Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.

        Specified by:
        append in interface  Appendable
        Overrides:
        append in class  Writer
        Parameters:
        csq - The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
        Returns:
        This writer
        Since:
        1.5
      • append

        public StringWriter append(CharSequence csq,
                                   int start,
                                   int end)
        Appends a subsequence of the specified character sequence to this writer.

        An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation

             out.write(csq.subSequence(start, end).toString()) 
        Specified by:
        append in interface  Appendable
        Overrides:
        append in class  Writer
        Parameters:
        csq - The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".
        start - The index of the first character in the subsequence
        end - The index of the character following the last character in the subsequence
        Returns:
        This writer
        Throws:
        IndexOutOfBoundsException - If start or end are negative, start is greater than end, or end is greater than csq.length()
        Since:
        1.5
      • append

        public StringWriter append(char c)
        Appends the specified character to this writer.

        An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation

             out.write(c) 
        Specified by:
        append in interface  Appendable
        Overrides:
        append in class  Writer
        Parameters:
        c - The 16-bit character to append
        Returns:
        This writer
        Since:
        1.5
      • toString

        public String toString()
        Return the buffer's current value as a string.
        Overrides:
        toString in class  Object
        Returns:
        a string representation of the object.
      • getBuffer

        public StringBuffer getBuffer()
        Return the string buffer itself.
        Returns:
        StringBuffer holding the current buffer value.
      • flush

        public void flush()
        Flush the stream.
      • close

        public void close()
                   throws IOException
        Closing a StringWriter has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
        Specified by:
        close in interface  Closeable
        Specified by:
        close in interface  AutoCloseable
        Specified by:
        close in class  Writer
        Throws:
        IOException - If an I/O error occurs