student.testingsupport

Class PrintWriterWithHistory

java.lang.Object

java.io.Writer

java.io.PrintWriter

student.testingsupport.PrintWriterWithHistory

All Implemented Interfaces:

Closeable, Flushable, Appendable, AutoCloseable

public class PrintWriterWithHistory
extends PrintWriter

An enhanced version of PrintWriter that provides for a history recall function and some other features making I/O testing a bit easier to perform. See the documentation for PrintWriter for more thorough details on what methods are provided.

Version:

$Revision: 1.4 $, $Date: 2015/08/20 13:01:51 $

Author:

Stephen Edwards, Last changed by $Author: stedwar2 $

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	PrintWriterWithHistory.NullWriter This is an inner class that is used for "null" destinations, such as in the default constructor for PrintWriterWithHistory.

Field Summary

Fields inherited from class java.io.PrintWriter

out

Fields inherited from class java.io.Writer

lock

Constructor Summary

Constructors

Constructor and Description
PrintWriterWithHistory() Create a new PrintWriter with no destination--useful when you just want to record the history (for testing, for example).
PrintWriterWithHistory(File file) Creates a new PrintWriter, without automatic line flushing, with the specified file.
PrintWriterWithHistory(File file, String csn) Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.
PrintWriterWithHistory(OutputStream out) Create a new PrintWriter, with automatic line flushing, from an existing OutputStream.
PrintWriterWithHistory(OutputStream out, boolean autoFlush) Create a new PrintWriter from an existing OutputStream.
PrintWriterWithHistory(String fileName) Creates a new PrintWriter, without automatic line flushing, with the specified file name.
PrintWriterWithHistory(String fileName, String csn) Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.
PrintWriterWithHistory(Writer out) Create a new PrintWriter, without automatic line flushing.
PrintWriterWithHistory(Writer out, boolean autoFlush) Create a new PrintWriter.

Method Summary

Modifier and Type	Method and Description
void	clearHistory() Reset this object's history to be empty, just as when the object was first created.
String	getHistory() Retrieve the text history of what has been sent to this PrintWriter.
boolean	getNormalizeLineEndings() Returns whether this object's history has normalized unix-style line endings, or the raw line endings generated by printing.
void	println() Terminate the current line by writing the line separator string.
void	setNormalizeLineEndings(boolean value) Set whether this object's history will have normalized unix-style line endings, or the raw line endings generated by printing.
void	write(char[] buf, int off, int len) Write A Portion of an array of characters.
void	write(int c) Write a single character.
void	write(String s, int off, int len) Write a portion of a string.

Methods inherited from class java.io.PrintWriter

append, append, append, checkError, clearError, close, flush, format, format, print, print, print, print, print, print, print, print, print, printf, printf, println, println, println, println, println, println, println, println, println, setError, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

PrintWriterWithHistory

public PrintWriterWithHistory()

Create a new PrintWriter with no destination--useful when you just want to record the history (for testing, for example). If you want to create a PrintWriter that points to System.out instead, use this:

 new PrintWriterWithHistory(System.out);
 

PrintWriterWithHistory

public PrintWriterWithHistory(Writer out)

Create a new PrintWriter, without automatic line flushing.

Parameters:

out - A character-output stream

PrintWriterWithHistory

public PrintWriterWithHistory(Writer out,
                              boolean autoFlush)

Create a new PrintWriter.

Parameters:

out - A character-output stream

autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer

PrintWriterWithHistory

public PrintWriterWithHistory(OutputStream out)

Create a new PrintWriter, with automatic line flushing, from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding. It differs from the corresponding constructor in PrintWriter by forcing automatic line flushing on instead of off, since students most often use it to pass in something like System.out.

Parameters:

out - An output stream

See Also:

OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)

PrintWriterWithHistory

public PrintWriterWithHistory(OutputStream out,
                              boolean autoFlush)

Create a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.

Parameters:

out - An output stream

autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer

See Also:

OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)

PrintWriterWithHistory

public PrintWriterWithHistory(String fileName)
                       throws FileNotFoundException

Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will encode characters using the default charset for this instance of the Java virtual machine.

Parameters:

fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

Throws:

FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file

PrintWriterWithHistory

public PrintWriterWithHistory(String fileName,
                              String csn)
                       throws FileNotFoundException,
                              UnsupportedEncodingException

Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will encode characters using the provided charset.

Parameters:

fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

csn - The name of a supported charset

Throws:

FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file

UnsupportedEncodingException - If the named charset is not supported

PrintWriterWithHistory

public PrintWriterWithHistory(File file)
                       throws FileNotFoundException

Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will encode characters using the default charset for this instance of the Java virtual machine.

Parameters:

file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

Throws:

FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file

PrintWriterWithHistory

public PrintWriterWithHistory(File file,
                              String csn)
                       throws FileNotFoundException,
                              UnsupportedEncodingException

Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will encode characters using the provided charset.

Parameters:

file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.

csn - The name of a supported charset

Throws:

FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file

UnsupportedEncodingException - If the named charset is not supported

Method Detail

getHistory

public String getHistory()

Retrieve the text history of what has been sent to this PrintWriter. This will include all text printed through this object. The clearHistory() method resets the history to be empty, just as when the object was first created. Note that newline characters in the history are always represented by '\n', regardless of what value the system line.separator property has.

Returns:

all the text sent to this PrintWriter

clearHistory

public void clearHistory()

Reset this object's history to be empty, just as when the object was first created. You can access the history using getHistory().

setNormalizeLineEndings

public void setNormalizeLineEndings(boolean value)

Set whether this object's history will have normalized unix-style line endings, or the raw line endings generated by printing. The default for this is true, so history values will automatically be normalized unless this method is used to change that behavior.

Parameters:

value - If true, the retrieved history will have all line endings automatically standardized to unix-style ("\n") line endings; if fase, the retrieved history will be presented without any modifications, using whatever (platform-specific) line endings were printed to this object.

getNormalizeLineEndings

public boolean getNormalizeLineEndings()

Returns whether this object's history has normalized unix-style line endings, or the raw line endings generated by printing. The default behavior is to normalize line endings.

Returns:

True if line endings will be normalized in the history.

write

public void write(int c)

Write a single character.

Overrides:

write in class PrintWriter

Parameters:

c - int specifying a character to be written.

write

public void write(char[] buf,
                  int off,
                  int len)

Write A Portion of an array of characters.

Overrides:

write in class PrintWriter

Parameters:

buf - Array of characters

off - Offset from which to start writing characters

len - Number of characters to write

write

public void write(String s,
                  int off,
                  int len)

Write a portion of a string.

Overrides:

write in class PrintWriter

Parameters:

s - A String

off - Offset from which to start writing characters

len - Number of characters to write

println

public void println()

Terminate 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').

Overrides:

println in class PrintWriter