print directory tree

algorithm, java

Solution

This is how I did it.

The Code

import java.io.File;
public class FileAssert {

/**
 * Pretty print the directory tree and its file names.
 * 
 * @param folder
 *            must be a folder.
 * @return
 */
public static String printDirectoryTree(File folder) {
    if (!folder.isDirectory()) {
        throw new IllegalArgumentException("folder is not a Directory");
    }
    int indent = 0;
    StringBuilder sb = new StringBuilder();
    printDirectoryTree(folder, indent, sb);
    return sb.toString();
}

private static void printDirectoryTree(File folder, int indent,
        StringBuilder sb) {
    if (!folder.isDirectory()) {
        throw new IllegalArgumentException("folder is not a Directory");
    }
    sb.append(getIndentString(indent));
    sb.append("+--");
    sb.append(folder.getName());
    sb.append("/");
    sb.append("\n");
    for (File file : folder.listFiles()) {
        if (file.isDirectory()) {
            printDirectoryTree(file, indent + 1, sb);
        } else {
            printFile(file, indent + 1, sb);
        }
    }

}

private static void printFile(File file, int indent, StringBuilder sb) {
    sb.append(getIndentString(indent));
    sb.append("+--");
    sb.append(file.getName());
    sb.append("\n");
}

private static String getIndentString(int indent) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < indent; i++) {
        sb.append("|  ");
    }
    return sb.toString();
}
}

The Result

+--folder1/
|  +--a.txt
|  +--folder2/
|  |  +--b1.txt
|  |  +--b2.txt
|  |  +--b3.txt
|  |  +--folder3/
|  +--folder4/

The UnitTest

import static org.junit.Assert.*;

import java.io.File;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class FileAssertTest {

@Rule
public TemporaryFolder temporaryFolder = new TemporaryFolder();
private File folder1;

@Before
public void setUp() {
    folder1 = temporaryFolder.newFolder("folder1");
}

@Test
public void testPrintDirectoryTreeWhenFolderIsEmpty() {
    // Invoke
    String actual = FileAssert.printDirectoryTree(folder1);
    // Verify
    assertEquals("+--folder1/\n", actual);
}

private static final String EXPECTED_FCOF = "" + "+--folder1/\n"
        + "|  +--a.txt\n";

@Test
public void testPrintDirectoryTreeWhenFolderContainsOneFile()
        throws Exception {
    // Setup
    File aFile = new File(folder1, "a.txt");
    assertTrue(aFile.createNewFile());
    // Invoke
    String actual = FileAssert.printDirectoryTree(folder1);
    // Verify
    assertEquals(EXPECTED_FCOF, actual);
}

private static final String EXPECTED_COMPLEX = "+--folder1/\n"
        + "|  +--a.txt\n" + "|  +--folder2/\n" + "|  |  +--b1.txt\n"
        + "|  |  +--b2.txt\n" + "|  |  +--b3.txt\n" + "|  |  +--folder3/\n"
        + "|  +--folder4/\n";

@Test
public void testPrintDirectoryTreeComplex() throws Exception {
    // Setup
    File aFile = new File(folder1, "a.txt");
    assertTrue(aFile.createNewFile());
    File folder2 = new File(folder1, "folder2");
    assertTrue(folder2.mkdir());
    File b1File = new File(folder2, "b1.txt");
    assertTrue(b1File.createNewFile());
    File b2File = new File(folder2, "b2.txt");
    assertTrue(b2File.createNewFile());
    File folder3 = new File(folder2, "folder3");
    assertTrue(folder3.mkdir());
    File b3File = new File(folder2, "b3.txt");
    assertTrue(b3File.createNewFile());
    File folder4 = new File(folder1, "folder4");
    assertTrue(folder4.mkdir());

    // Invoke
    String actual = FileAssert.printDirectoryTree(folder1);
    // Verify
    assertEquals(EXPECTED_COMPLEX, actual);
}

}

file directory printing pretty-printing

Problem

I have to print a directory tree (like tree command), example: ``` . +---A | +---IMAGES | +---BACKUP +---ADOKS | +---ROZDZIAL_2 | +---ROZDZIAL_3 | +---ROZDZIAL_4 +---AMSC2005 | +---AMSC2004 +---FCCS2005 | +---source | +---TMP +---LODZ2004 +---ZAKOPANE2004 +---DYDAKTYKA | +---DYDAKTYKA_ISI | | +---COLLS | | | +---Q1 | | | +---Q2 | | | +---RAZEM | | | +---RYSUNKI_COLL1 | | | +---RYSUNKI_COLL2 | | +---IMAGES | | +---src | | +---WYKLAD5 | +---DYDAKTYKA_PRG | +---images | +---POMOC +---DYDAKTYKA_KST | +---images | +---src +---DYDAKTYKA_WPR +---images +---src ``` I tried with the following Code: ``` private static void getInto(String p, int n) { File path = new File(p); File[] list = path.listFiles(); for (int i = 0; i < list.length; i++) { if (list[i].isDirectorhowny()) { for (int j = 0; j < n; j++) if (WHAT HERE?) System.out.print("| "); else System.out.print(" "); System.out.println("+--" + list[i].getName().toString()); getInto(list[i].getPath(), n + 1); } } } ``` I tried few version, but it's still not work. How to do this? What condition should be put in If? I know is pretty simple, but I can't do this.

Original source

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