Package java.io

Class PrintStream

  • All Implemented Interfaces:
    Closeable, Flushable, Appendable, AutoCloseable
    public class PrintStream
extends FilterOutputStream
implements Appendable, Closeable
    A PrintStream adds functionality to another output stream, namely the ability to print representations of various data values conveniently. Two other features are provided as well. Unlike other output streams, a PrintStream never throws an IOException; instead, exceptional situations merely set an internal flag that can be tested via the checkError method. Optionally, a PrintStream can be created so as to flush automatically; this means that the flush method is automatically invoked after a byte array is written, one of the println methods is invoked, or a newline character or byte ('\n') is written.

    All characters printed by a PrintStream are converted into bytes using the platform's default character encoding.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      PrintStream append​(char c)
      Appends the specified character to this output stream.
      PrintStream append​(CharSequence csq)
      Appends the specified character sequence to this output stream.
      PrintStream append​(CharSequence csq, int start, int end)
      Appends a subsequence of the specified character sequence to this output stream.
      boolean checkError()
      Flushes the stream and checks its error state.
      protected void clearError()
      Clears the internal error state of this stream.
      void close()
      Closes the stream.
      void flush()
      Flushes the stream.
      void print​(boolean b)
      Prints a boolean value.
      void print​(char c)
      Prints a character.
      void print​(char[] s)
      Prints an array of characters.
      void print​(double d)
      Prints a double-precision floating-point number.
      void print​(float f)
      Prints a floating-point number.
      void print​(int i)
      Prints an integer.
      void print​(long l)
      Prints a long integer.
      void print​(Object obj)
      Prints an object.
      void print​(String s)
      Prints a string.
      void println()
      Terminates the current line by writing the line separator string.
      void println​(boolean x)
      Prints a boolean and then terminate the line.
      void println​(char x)
      Prints a character and then terminate the line.
      void println​(char[] x)
      Prints an array of characters and then terminate the line.
      void println​(double x)
      Prints a double and then terminate the line.
      void println​(float x)
      Prints a float and then terminate the line.
      void println​(int x)
      Prints an integer and then terminate the line.
      void println​(long x)
      Prints a long and then terminate the line.
      void println​(Object x)
      Prints an Object and then terminate the line.
      void println​(String x)
      Prints a String and then terminate the line.
      protected void setError()
      Sets the error state of the stream to true.
      void write​(byte[] buf, int off, int len)
      Writes len bytes from the specified byte array starting at offset off to this stream.
      void write​(int b)
      Writes the specified byte to this stream.

    • Constructor Detail

      • PrintStream

        public PrintStream​(OutputStream out)
        Creates a new print stream. This stream will not flush automatically.
        Parameters:
        out - The output stream to which values and objects will be printed

      • PrintStream

        public PrintStream​(OutputStream out,
                   boolean autoFlush)
        Creates a new print stream.
        Parameters:
        out - The output stream to which values and objects will be printed
        autoFlush - A boolean; if true, the output buffer will be flushed whenever a byte array is written, one of the println methods is invoked, or a newline character or byte ('\n') is written

      • PrintStream

        public PrintStream​(OutputStream out,
                   boolean autoFlush,
                   String encoding)
            throws UnsupportedEncodingException
        Creates a new print stream.
        Parameters:
        out - The output stream to which values and objects will be printed
        autoFlush - A boolean; if true, the output buffer will be flushed whenever a byte array is written, one of the println methods is invoked, or a newline character or byte ('\n') is written
        encoding - The name of a supported character encoding
        Throws:
        UnsupportedEncodingException - If the named encoding is not supported

    • Method Detail

      • append

        public PrintStream append​(char c)
        Appends the specified character to this output stream.

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

         out.print(c)
        Specified by:
        append in interface Appendable
        Parameters:
        c - The 16-bit character to append
        Returns:
        This output stream

      • append

        public PrintStream append​(@Nullable
                          CharSequence csq)
        Appends the specified character sequence to this output stream.

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

         out.print(csq.toString())

        Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking then 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
        Parameters:
        csq - The character sequence to append. If csq is null, then the four characters "null" are appended to this output stream.
        Returns:
        This output stream

      • append

        public PrintStream append​(@Nullable
                          CharSequence csq,
                          int start,
                          int end)
        Appends a subsequence of the specified character sequence to this output stream.

        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.print(csq.subSequence(start, end).toString())
        Specified by:
        append in interface Appendable
        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 output stream
        Throws:
        IndexOutOfBoundsException - If start or end are negative, start is greater than end, or end is greater than csq.length()

      • checkError

        public boolean checkError()
        Flushes the stream and checks its error state. The internal error state is set to true when the underlying output stream throws an IOException other than InterruptedIOException, and when the setError method is invoked. If an operation on the underlying output stream throws an InterruptedIOException, then the PrintStream converts the exception back into an interrupt by doing: 
         Thread.currentThread().interrupt();
        or the equivalent.
        Returns:
        true if and only if this stream has encountered an IOException other than InterruptedIOException, or the setError method has been invoked

      • clearError

        protected void clearError()
        Clears the internal error state of this stream.

        This method will cause subsequent invocations of checkError() to return false until another write operation fails and invokes setError().

      • flush

        public void flush()
        Flushes the stream. This is done by writing any buffered output bytes to the underlying output stream and then flushing that stream.
        Specified by:
        flush in interface Flushable
        Overrides:
        flush in class FilterOutputStream
        See Also:
        OutputStream.flush()

      • print

        public void print​(boolean b)
        Prints a boolean value. The string produced by String.valueOf(boolean) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        b - The boolean to be printed

      • print

        public void print​(char c)
        Prints a character. The character is translated into one or more bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        c - The char to be printed

      • print

        public void print​(char[] s)
        Prints an array of characters. The characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        s - The array of chars to be printed
        Throws:
        NullPointerException - If s is null

      • print

        public void print​(double d)
        Prints a double-precision floating-point number. The string produced by String.valueOf(double) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        d - The double to be printed
        See Also:
        Double.toString(double)

      • print

        public void print​(float f)
        Prints a floating-point number. The string produced by String.valueOf(float) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        f - The float to be printed
        See Also:
        Float.toString(float)

      • print

        public void print​(int i)
        Prints an integer. The string produced by String.valueOf(int) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        i - The int to be printed
        See Also:
        Integer.toString(int)

      • print

        public void print​(long l)
        Prints a long integer. The string produced by String.valueOf(long) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        l - The long to be printed
        See Also:
        Long.toString(long)

      • print

        public void print​(@Nullable
                  Object obj)
        Prints an object. The string produced by the String.valueOf(Object) method is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        obj - The Object to be printed
        See Also:
        Object.toString()

      • print

        public void print​(@Nullable
                  String s)
        Prints a string. If the argument is null then the string "null" is printed. Otherwise, the string's characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
        Parameters:
        s - The String to be printed

      • println

        public void println()
        Terminates the current line by writing the line separator string. The line separator string is defined by the system property line.separator, and is not necessarily a single newline character ('\n').

      • println

        public void println​(boolean x)
        Prints a boolean and then terminate the line. This method behaves as though it invokes print(boolean) and then println().
        Parameters:
        x - The boolean to be printed

      • println

        public void println​(char x)
        Prints a character and then terminate the line. This method behaves as though it invokes print(char) and then println().
        Parameters:
        x - The char to be printed.

      • println

        public void println​(char[] x)
        Prints an array of characters and then terminate the line. This method behaves as though it invokes print(char[]) and then println().
        Parameters:
        x - an array of chars to print.

      • println

        public void println​(double x)
        Prints a double and then terminate the line. This method behaves as though it invokes print(double) and then println().
        Parameters:
        x - The double to be printed.

      • println

        public void println​(float x)
        Prints a float and then terminate the line. This method behaves as though it invokes print(float) and then println().
        Parameters:
        x - The float to be printed.

      • println

        public void println​(int x)
        Prints an integer and then terminate the line. This method behaves as though it invokes print(int) and then println().
        Parameters:
        x - The int to be printed.

      • println

        public void println​(long x)
        Prints a long and then terminate the line. This method behaves as though it invokes print(long) and then println().
        Parameters:
        x - a The long to be printed.

      • println

        public void println​(@Nullable
                    Object x)
        Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes print(String) and then println().
        Parameters:
        x - The Object to be printed.

      • println

        public void println​(@Nullable
                    String x)
        Prints a String and then terminate the line. This method behaves as though it invokes print(String) and then println().
        Parameters:
        x - The String to be printed.

      • setError

        protected void setError()
        Sets the error state of the stream to true.

        This method will cause subsequent invocations of checkError() to return true until clearError() is invoked.

      • write

        public void write​(byte[] buf,
                  int off,
                  int len)
        Writes len bytes from the specified byte array starting at offset off to this stream. If automatic flushing is enabled then the flush method will be invoked.

        Note that the bytes will be written as given; to write characters that will be translated according to the platform's default character encoding, use the print(char) or println(char) methods.

        Overrides:
        write in class FilterOutputStream
        Parameters:
        buf - A byte array
        off - Offset from which to start taking bytes
        len - Number of bytes to write
        See Also:
        FilterOutputStream.write(int)

      • write

        public void write​(int b)
        Writes the specified byte to this stream. If the byte is a newline and automatic flushing is enabled then the flush method will be invoked.

        Note that the byte is written as given; to write a character that will be translated according to the platform's default character encoding, use the print(char) or println(char) methods.

        Overrides:
        write in class FilterOutputStream
        Parameters:
        b - The byte to be written
        See Also:
        print(char), println(char)