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[TOREVIEW] Lab Java IO #3

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92 changes: 49 additions & 43 deletions LabJavaIO/src/main/java/ch/heigvd/res/labio/impl/Application.java
Original file line number Diff line number Diff line change
Expand Up @@ -5,73 +5,72 @@
import ch.heigvd.res.labio.interfaces.IApplication;
import ch.heigvd.res.labio.interfaces.IFileExplorer;
import ch.heigvd.res.labio.interfaces.IFileVisitor;
import ch.heigvd.res.labio.quotes.QuoteClient;
import ch.heigvd.res.labio.quotes.Quote;
import ch.heigvd.res.labio.quotes.QuoteClient;
import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.io.FileUtils;

/**
*
* @author Olivier Liechti
*/
public class Application implements IApplication {

private static final Logger LOG = Logger.getLogger(Application.class.getName());
/**
* This constant defines where the quotes will be stored. The path is relative
* to where the Java application is invoked.
*/
public static String WORKSPACE_DIRECTORY = "./workspace/quotes";

private static final Logger LOG = Logger.getLogger(Application.class.getName());


public static void main(String[] args) {

/*
* I prefer to have LOG output on a single line, it's easier to read. Being able
* to change the formatting of console outputs is one of the reasons why it is
* better to use a Logger rather than using System.out.println
*/
System.setProperty("java.util.logging.SimpleFormatter.format", "%4$s: %5$s%6$s%n");


int numberOfQuotes = 0;
try {
numberOfQuotes = Integer.parseInt(args[0]);
} catch (Exception e) {
System.err.println("The command accepts a single numeric argument (number of quotes to fetch)");
System.exit(-1);
}

Application app = new Application();
try {
/*
* Step 1 : clear the output directory
*/
app.clearOutputDirectory();

/*
* Step 2 : use the QuotesClient to fetch quotes; store each quote in a file
*/
app.fetchAndStoreQuotes(numberOfQuotes);

/*
* Step 3 : use a file explorer to traverse the file system; print the name of each directory and file
*/
Writer writer = new StringWriter(); // we create a special writer that will send characters into a string (memory)
app.printFileNames(writer); // we hand over this writer to the printFileNames method
LOG.info(writer.toString()); // we dump the whole result on the console

/*
* Step 4 : process the quote files, by applying 2 transformations to their content
* (convert to uppercase and add line numbers)
*/
app.processQuoteFiles();

} catch (IOException ex) {
LOG.log(Level.SEVERE, "Could not fetch quotes. {0}", ex.getMessage());
ex.printStackTrace();
Expand All @@ -84,48 +83,56 @@ public void fetchAndStoreQuotes(int numberOfQuotes) throws IOException {
QuoteClient client = new QuoteClient();
for (int i = 0; i < numberOfQuotes; i++) {
Quote quote = client.fetchQuote();
/* There is a missing piece here!
* As you can see, this method handles the first part of the lab. It uses the web service
* client to fetch quotes. We have removed a single line from this method. It is a call to
* one method provided by this class, which is responsible for storing the content of the
* quote in a text file (and for generating the directories based on the tags).
*/
storeQuote(quote, "quote-" + i + ".utf8");
LOG.info("Received a new joke with " + quote.getTags().size() + " tags.");
for (String tag : quote.getTags()) {
LOG.info("> " + tag);
}
}
}

/**
* This method deletes the WORKSPACE_DIRECTORY and its content. It uses the
* apache commons-io library. You should call this method in the main method.
*
* @throws IOException
*
* @throws IOException
*/
void clearOutputDirectory() throws IOException {
FileUtils.deleteDirectory(new File(WORKSPACE_DIRECTORY));
FileUtils.deleteDirectory(new File(WORKSPACE_DIRECTORY));
}

/**
* This method stores the content of a quote in the local file system. It has
* 2 responsibilities:
*
* 2 responsibilities:
* <p>
* - with quote.getTags(), it gets a list of tags and uses
* it to create sub-folders (for instance, if a quote has three tags "A", "B" and
* "C", it will be stored in /quotes/A/B/C/quotes-n.utf8.
*
* it to create sub-folders (for instance, if a quote has three tags "A", "B" and
* "C", it will be stored in /quotes/A/B/C/quotes-n.utf8.
* <p>
* - with quote.getQuote(), it has access to the text of the quote. It stores
* this text in UTF-8 file.
*
* @param quote the quote object, with tags and text
* this text in UTF-8 file.
*
* @param quote the quote object, with tags and text
* @param filename the name of the file to create and where to store the quote text
* @throws IOException
* @throws IOException
*/
void storeQuote(Quote quote, String filename) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
StringBuilder hierarchy = new StringBuilder(WORKSPACE_DIRECTORY);

// Create directory hierarchy
for (String tag : quote.getTags())
hierarchy.append("/").append(tag);

// Append file
hierarchy.append("/").append(filename);

// Create file with filename and hierarchy
File file = new File(hierarchy.toString());

// Write quote in file
FileUtils.write(file, quote.getQuote());
}

/**
* This method uses a IFileExplorer to explore the file system and prints the name of each
* encountered file and directory.
Expand All @@ -135,19 +142,18 @@ void printFileNames(final Writer writer) {
explorer.explore(new File(WORKSPACE_DIRECTORY), new IFileVisitor() {
@Override
public void visit(File file) {
/*
* There is a missing piece here. Notice how we use an anonymous class here. We provide the implementation
* of the the IFileVisitor interface inline. You just have to add the body of the visit method, which should
* be pretty easy (we want to write the filename, including the path, to the writer passed in argument).
*/
try {
writer.write(file.getPath() + "\n");
} catch (IOException e) {
e.printStackTrace();
}
}
});
}

@Override
public void processQuoteFiles() throws IOException {
IFileExplorer explorer = new DFSFileExplorer();
explorer.explore(new File(WORKSPACE_DIRECTORY), new CompleteFileTransformer());
explorer.explore(new File(WORKSPACE_DIRECTORY), new CompleteFileTransformer());
}

}
}
22 changes: 18 additions & 4 deletions LabJavaIO/src/main/java/ch/heigvd/res/labio/impl/Utils.java
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@
import java.util.logging.Logger;

/**
*
* @author Olivier Liechti
*/
public class Utils {
Expand All @@ -12,15 +11,30 @@ public class Utils {

/**
* This method looks for the next new line separators (\r, \n, \r\n) to extract
* the next line in the string passed in arguments.
*
* the next line in the string passed in arguments.
*
* @param lines a string that may contain 0, 1 or more lines
* @return an array with 2 elements; the first element is the next line with
* the line separator, the second element is the remaining text. If the argument does not
* contain any line separator, then the first element is an empty string.
*/
public static String[] getNextLine(String lines) {
throw new UnsupportedOperationException("The student has not implemented this method yet.");

// New line & Carriage return
if (lines.contains("\r\n"))
return lines.split("(?<=\r\n)", 2);

// New line
else if (lines.contains("\n"))
return lines.split("(?<=\n)", 2);

// Carriage return
else if (lines.contains("\r"))
return lines.split("(?<=\r)", 2);

else // Empty
return new String[]{"", lines};

}

}
Original file line number Diff line number Diff line change
Expand Up @@ -2,21 +2,33 @@

import ch.heigvd.res.labio.interfaces.IFileExplorer;
import ch.heigvd.res.labio.interfaces.IFileVisitor;

import java.io.File;
import java.util.Arrays;

/**
* This implementation of the IFileExplorer interface performs a depth-first
* exploration of the file system and invokes the visitor for every encountered
* node (file and directory). When the explorer reaches a directory, it visits all
* files in the directory and then moves into the subdirectories.
*
*
* @author Olivier Liechti
*/
public class DFSFileExplorer implements IFileExplorer {

@Override
public void explore(File rootDirectory, IFileVisitor vistor) {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
public void explore(File rootDirectory, IFileVisitor visitor) {

// Visit files in the current directory
visitor.visit(rootDirectory);

File[] files = rootDirectory.listFiles();
if (files != null) {
for (File file : files)
explore(file, visitor); // Recursion
}

}

}

Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
* When filter encounters a line separator, it sends it to the decorated writer.
* It then sends the line number and a tab character, before resuming the write
* process.
*
* <p>
* Hello\n\World -> 1\Hello\n2\tWorld
*
* @author Olivier Liechti
Expand All @@ -19,23 +19,52 @@ public class FileNumberingFilterWriter extends FilterWriter {

private static final Logger LOG = Logger.getLogger(FileNumberingFilterWriter.class.getName());

public FileNumberingFilterWriter(Writer out) {
super(out);
}
private int nbLine = 1;
private boolean newLine = true;

public FileNumberingFilterWriter(Writer out) { super(out); }

@Override
public void write(String str, int off, int len) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
for (int index = off; index < (off + len); index++)
this.write(str.charAt(index));
}

@Override
public void write(char[] cbuf, int off, int len) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
for (int index = off; index < (off + len); index++)
this.write(cbuf[index]);
}

@Override
public void write(int c) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");

// New line
if (c == '\n') {
newLine = false;
super.write(c);
writeLineNbr();

} else if (c == '\r') { // Carriage return
newLine = true;
super.write(c);

} else { // Not an escape char

if (newLine) {
newLine = false;
writeLineNbr();
}

super.write(c);
}

}

private void writeLineNbr() throws IOException {

int len = String.valueOf(nbLine).length();
super.write(Integer.toString(nbLine++), 0, len);
super.write('\t');
}
}
Original file line number Diff line number Diff line change
Expand Up @@ -9,24 +9,24 @@
* @author Olivier Liechti
*/
public class UpperCaseFilterWriter extends FilterWriter {

public UpperCaseFilterWriter(Writer wrappedWriter) {
super(wrappedWriter);
}

@Override
public void write(String str, int off, int len) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
super.write(str.toUpperCase(), off, len);
}

@Override
public void write(char[] cbuf, int off, int len) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
this.write(new String(cbuf), off, len);
}

@Override
public void write(int c) throws IOException {
throw new UnsupportedOperationException("The student has not implemented this method yet.");
super.write(Character.toUpperCase(c));
}

}
}
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