OnJava8-Examples/onjava/Directory.java
2015-11-15 15:51:35 -08:00

105 lines
3.1 KiB
Java

// onjava/Directory.java
// ©2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
// Produce a sequence of File objects that match a
// regular expression in either a local directory,
// or by walking a directory tree.
package onjava;
import java.util.regex.*;
import java.io.*;
import java.util.*;
public final class Directory {
public static File[]
local(File dir, final String regex) {
return dir.listFiles(new FilenameFilter() {
private Pattern pattern = Pattern.compile(regex);
@Override
public boolean accept(File dir, String name) {
return pattern.matcher(
new File(name).getName()).matches();
}
});
}
public static File[]
local(String path, final String regex) { // Overloaded
return local(new File(path), regex);
}
// A two-tuple for returning a pair of objects:
public static class TreeInfo implements Iterable<File> {
public List<File> files = new ArrayList<>();
public List<File> dirs = new ArrayList<>();
// The default iterable element is the file list:
@Override
public Iterator<File> iterator() {
return files.iterator();
}
void addAll(TreeInfo other) {
files.addAll(other.files);
dirs.addAll(other.dirs);
}
@Override
public String toString() {
return "dirs: " + PPrint.pformat(dirs) +
"\n\nfiles: " + PPrint.pformat(files);
}
}
public static TreeInfo
walk(String start, String regex) { // Begin recursion
return recurseDirs(new File(start), regex);
}
public static TreeInfo
walk(File start, String regex) { // Overloaded
return recurseDirs(start, regex);
}
public static TreeInfo walk(File start) { // Everything
return recurseDirs(start, ".*");
}
public static TreeInfo walk(String start) {
return recurseDirs(new File(start), ".*");
}
static TreeInfo recurseDirs(File startDir, String regex){
TreeInfo result = new TreeInfo();
for(File item : startDir.listFiles()) {
if(item.isDirectory()) {
result.dirs.add(item);
result.addAll(recurseDirs(item, regex));
} else // Regular file
if(item.getName().matches(regex))
result.files.add(item);
}
return result;
}
// Simple validation test:
public static void main(String[] args) {
if(args.length == 0)
System.out.println(walk("."));
else
for(String arg : args)
System.out.println(walk(arg));
}
}
/* Output: (First 20 Lines)
dirs: []
files: [
.\BasicSupplier.class
.\BasicSupplier.java
.\BinaryFile.class
.\BinaryFile.java
.\CollectionData.class
.\CollectionData.java
.\ContainerMethodDifferences-erroroutput.txt
.\ContainerMethodDifferences-output.txt
.\ContainerMethodDifferences.class
.\ContainerMethodDifferences.java
.\ConvertTo.class
.\ConvertTo.java
.\CountingSupplier$Boolean.class
.\CountingSupplier$Byte.class
.\CountingSupplier$Character.class
.\CountingSupplier$Double.class
.\CountingSupplier$Float.class
...
*/