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ConnectToDatabaseJDBC.java
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; public class ConnectToDatabaseJDBC { public static Connection getConnection1(String serverName, int port, String database, String driver, String username, String password) throws SQLException { Connection conn = null; Properties props = new Properties(); props.put("user", username); props.put("password", password); String url = "jdbc:" + driver + "://" + serverName + ":" + port + "/" + database; conn = DriverManager.getConnection(url, props); return conn; } public static Connection getConnection2(String serverName, int port, String database, String driver, String username, String password) throws SQLException { Connection conn = null; String url = "jdbc:" + driver + "://" + serverName + ":" + port + "/" + database; conn = DriverManager.getConnection(url, username, password); return conn; } }
CallMethodUsingReflection.java
import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.NoSuchElementException; //((getMethod)|(getDeclaredMethod)) //invoke public class CallMethodUsingReflection { public static Object callMethod1(Object object, String methodName, Object args[]) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { //Caveat: this solution doesn't support some method signatures (e.g., those with primitive types) Class<?> myClass = object.getClass(); Class<?>[] ptypes = new Class[args.length]; for(int i = 0; i < args.length; i++) { ptypes[i] = args[i].getClass(); } Method method = myClass.getMethod(methodName, ptypes); Object returnVal = method.invoke(object, args); return returnVal; } public static Object callMethod2(Object object, String methodName, Object params[], Class[] types) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { // Uses getMethod Class<?> myClass = object.getClass(); Method method = myClass.getMethod(methodName, types); Object returnVal = method.invoke(object, params); return returnVal; } public static Object callMethod3(Object object, String methodName, Object params[], Class[] types) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { // Uses getDeclaredMethod and climbs up the superclasses Method method = null; Class<?> myClass = object.getClass(); NoSuchMethodException ex = null; while(method == null && myClass != null) { try { method = myClass.getDeclaredMethod(methodName, types); } catch (NoSuchMethodException e) { ex = e; myClass = myClass.getSuperclass(); } } if(method == null) throw ex; Object returnVal = method.invoke(object, params); return returnVal; } public static void main(String args[]) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { Integer[] params = {}; Class[] types = {}; Object retval = CallMethodUsingReflection.callMethod3(new GCD(), "getClass", (Object []) params, types); System.out.println(retval); } }
ConvertDateFormat.java
import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; public class ConvertDateFormat { public static String convertDateFormat(String date, String srcFormat, String destFormat) throws ParseException { // Parse date string into a Date object using the source format DateFormat sFormat = new SimpleDateFormat(srcFormat); Date srcDate = sFormat.parse(date); // Format the data object to produce a string using the destination format DateFormat dFormat = new SimpleDateFormat(destFormat); String retval = dFormat.format(srcDate); // Return return retval; } }
BubbleSort.java
public class BubbleSort { public static void BubbleSortInt1(int[] num) { boolean flag = true; // set flag to true to begin first pass int temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortInt2(int[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { int temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static void BubbleSortFloat1(float[] num) { boolean flag = true; // set flag to true to begin first pass float temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortFloat2(float[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { float temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static void BubbleSortDouble1(double[] num) { boolean flag = true; // set flag to true to begin first pass double temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortDouble2(double[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { double temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static void BubbleSortLong1(long[] num) { boolean flag = true; // set flag to true to begin first pass long temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortLong2(long[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { long temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static void BubbleSortShort1(short[] num) { boolean flag = true; // set flag to true to begin first pass short temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortShort2(short[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { short temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static void BubbleSortByte1(byte[] num) { boolean flag = true; // set flag to true to begin first pass byte temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static void BubbleSortByte2(byte[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j] > num[j + 1]) { byte temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } public static <T extends Comparable<T>> void BubbleSortComparable1(T[] num) { int j; boolean flag = true; // set flag to true to begin first pass T temp; // holding variable while (flag) { flag = false; // set flag to false awaiting a possible swap for (j = 0; j < num.length - 1; j++) { if (num[j].compareTo(num[j + 1]) > 0) // change to > for ascending sort { temp = num[j]; // swap elements num[j] = num[j + 1]; num[j + 1] = temp; flag = true; // shows a swap occurred } } } } public static <T extends Comparable<T>> void BubbleSortComparable2(T[] num) { int last_exchange; int right_border = num.length - 1; do { last_exchange = 0; for (int j = 0; j < num.length - 1; j++) { if (num[j].compareTo(num[j + 1]) > 0) { T temp = num[j]; num[j] = num[j + 1]; num[j + 1] = temp; last_exchange = j; } } right_border = last_exchange; } while (right_border > 0); } }
BinarySearch.java
public class BinarySearch { //Heuristic: (([0-9,a-z,A-Z,_,$]+\s*\=\s*\(\s*[0-9,a-z,A-Z,_,$]+\s*\+\s*[0-9,a-z,A-Z,_,$]+\s*\)\s*/\s*2\s*;)|([0-9,a-z,A-Z,_,$]+\s*=\s*[0-9,a-z,A-Z,_,$]+\s*\+\s*\(\s*[0-9,a-z,A-Z,_,$]+\s*-\s*[0-9,a-z,A-Z,_,$]+\s*\)\s*/\s*2\s*;)) // imid = imin + (imax - imin)/2; // imid = (imax + imin)/2; public static int binarySearch1(int arr[], int key, int imin, int imax) { //Implementation: Recursive, primitive type if(imax < imin) return -1; int imid = (imin+imax)/2; if(arr[imid] > key) return binarySearch1(arr,key,imin,imid-1); else if (arr[imid] < key) return binarySearch1(arr,key,imid+1,imax); else return imid; } public static <T extends Comparable<T>> int binarySearch3(T[] arr, T key, int imin, int imax) { //Implementation: Recursive, comparable type if(imax < imin) return -1; int imid = (imin+imax)/2; if(arr[imid].compareTo(key) > 0) return binarySearch3(arr,key,imin,imid-1); else if (arr[imid].compareTo(key) < 0) return binarySearch3(arr,key,imid+1,imax); else return imid; } public static int binarySearch2(int arr[], int key) { //Implementation: Iterative, primitive type. int imin = 0; int imax = arr.length - 1; while(imin <= imax) { int imid = imin + (imax - imin)/2; if (key < arr[imid]) imax = imid-1; else if (key > arr[imid]) imin = imid + 1; else return imid; } return -1; } public static <T extends Comparable<T>> int binarySearch4(T[] arr, T key) { int imin = 0; int imax = arr.length - 1; while(imin <= imax) { int imid = imin + (imax - imin)/2; if (key.compareTo(arr[imid]) < 0)//(key < arr[imid]) imax = imid-1; else if (key.compareTo(arr[imid]) > 0)//(key > arr[imid]) imin = imid + 1; else return imid; } return -1; } }
CopyDirectoryTree.java
package database; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.file.FileVisitResult; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.SimpleFileVisitor; import java.nio.file.attribute.*; public class CopyDirectoryTree { // copy AND isDirectory AND list public static void copyDirectory1(Path src, Path dest) throws IOException { Files.copy(src, dest); if(Files.isDirectory(src)) { for(String filename : src.toFile().list()) { Path srcFile = src.resolve(filename); Path destFile = dest.resolve(filename); copyDirectory1(srcFile, destFile); } } } // preVisitDirectory AND visitFile AND walkFileTree AND copy public static void copyDirectory2(final Path src, final Path dest) throws IOException { Files.walkFileTree(src, new SimpleFileVisitor<Path>() { @Override public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException { Files.copy(dir, dest.resolve(src.relativize(dir))); return FileVisitResult.CONTINUE; } @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { Files.copy(file, dest.resolve(src.relativize(file))); return FileVisitResult.CONTINUE; } }); } }
CopyFileSamples.java
import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.nio.channels.FileChannel; import java.util.Scanner; import org.apache.commons.io.FileUtils; import org.apache.commons.io.IOUtils; public class CopyFileSamples { public static void copyFile1(File srcFile, File destFile) throws IOException { if(!destFile.exists()) { destFile.createNewFile(); } FileInputStream fis = new FileInputStream(srcFile); FileOutputStream fos = new FileOutputStream(destFile); FileChannel source = fis.getChannel(); FileChannel destination = fos.getChannel(); destination.transferFrom(source, 0, source.size()); source.close(); destination.close(); fis.close(); fos.close(); } public static void copyFile2(File srcFile, File destFile) throws IOException { FileUtils.copyFile(srcFile, destFile); } public static void copyFile3(File srcFile, File destFile) throws IOException { InputStream in = new FileInputStream(srcFile); OutputStream out = new FileOutputStream(destFile); byte[] buf = new byte[1024]; int len; while((len = in.read(buf)) > 0) { out.write(buf, 0, len); } in.close(); out.close(); } public static void copyFile4(File srcFile, File destFile) throws IOException { InputStream in = new FileInputStream(srcFile); OutputStream out = new FileOutputStream(destFile); IOUtils.copy(in, out); in.close(); out.close(); } public static void copyFile5(File srcFile, File destFile) throws IOException { InputStream in = new FileInputStream(srcFile); OutputStream out = new FileOutputStream(destFile); IOUtils.copyLarge(in, out); in.close(); out.close(); } public static void copyFile6(File srcFile, File destFile) throws FileNotFoundException { Scanner s = new Scanner(srcFile); PrintWriter pw = new PrintWriter(destFile); while(s.hasNextLine()) { pw.println(s.nextLine()); } pw.close(); s.close(); } }
CRC32FileChecksum.java
import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.util.zip.CRC32; public class CRC32FileChecksum { public static long checksum1(File file) throws IOException { CRC32 crc = new CRC32(); FileReader fr = new FileReader(file); int data; while((data = fr.read()) != -1) { crc.update(data); } fr.close(); return crc.getValue(); } }
CreateJavaProject.java
import org.eclipse.core.resources.IFolder; import org.eclipse.core.resources.IProject; import org.eclipse.core.resources.IProjectDescription; import org.eclipse.core.resources.IWorkspace; import org.eclipse.core.resources.IWorkspaceRoot; import org.eclipse.core.resources.ResourcesPlugin; import org.eclipse.core.runtime.CoreException; import org.eclipse.core.runtime.IPath; import org.eclipse.core.runtime.Path; import org.eclipse.jdt.core.IClasspathEntry; import org.eclipse.jdt.core.IJavaProject; import org.eclipse.jdt.core.JavaCore; public class CreateJavaProject { public static IProject CreateJavaProject(String name, IPath classpath) throws CoreException { // Create and Open New Project in Workspace IWorkspace workspace = ResourcesPlugin.getWorkspace(); IWorkspaceRoot root = workspace.getRoot(); IProject project = root.getProject(name); project.create(null); project.open(null); // Add Java Nature to new Project IProjectDescription desc = project.getDescription(); desc.setNatureIds(new String[] { JavaCore.NATURE_ID}); project.setDescription(desc, null); // Get Java Project Object IJavaProject javaProj = JavaCore.create(project); // Set Output Folder IFolder binDir = project.getFolder("bin"); IPath binPath = binDir.getFullPath(); javaProj.setOutputLocation(binPath, null); // Set Project's Classpath IClasspathEntry cpe = JavaCore.newLibraryEntry(classpath, null, null); javaProj.setRawClasspath(new IClasspathEntry[] {cpe}, null); return project; } }
CreateRSAKeys.java
import java.io.BufferedOutputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectOutputStream; import java.nio.file.Files; import java.nio.file.Path; import java.security.InvalidKeyException; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.PrivateKey; import java.security.PublicKey; import java.security.SecureRandom; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException; public class CreateRSAKeys { public static void main(String args[]) throws NoSuchAlgorithmException, IOException { System.out.println(generateKeys1()); } public static KeyPair generateKeys1() throws NoSuchAlgorithmException, IOException { //Minimum Example KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA"); KeyPair keyPair = keyGen.generateKeyPair(); return keyPair; } public static void generateKeys2(int keySize, Path publicKey, Path privateKey) throws NoSuchAlgorithmException, IOException { //Fuller Example KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA"); keyGen.initialize(keySize); KeyPair keyPair = keyGen.generateKeyPair(); PublicKey pubkey = keyPair.getPublic(); PrivateKey privkey = keyPair.getPrivate(); Files.createDirectories(publicKey.getParent()); Files.createFile(publicKey); Files.createDirectories(privateKey.getParent()); Files.createFile(privateKey); ObjectOutputStream oout = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(publicKey.toFile()))); oout.writeObject(pubkey); oout.close(); oout = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(privateKey.toFile()))); oout.writeObject(privkey); oout.close(); } }
DeleteFolderRecursively.java
import java.io.File; import java.io.IOException; import java.nio.file.FileVisitResult; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.SimpleFileVisitor; import java.nio.file.attribute.BasicFileAttributes; public class DeleteFolderRecursively { //isDirectory AND listFiles AND delete public static void deleteRecursively1(File file) { if (file.isDirectory()) { for (File f : file.listFiles()) deleteRecursively1(f); } file.delete(); } //walkFileTree AND delete AND postVisitDirectory AND visitFile public static void deleteRecursively1(Path dir) throws IOException { Files.walkFileTree(dir, new SimpleFileVisitor<Path>() { @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { Files.delete(file); return FileVisitResult.CONTINUE; } @Override public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException { // try to delete the file anyway, even if its attributes // could not be read, since delete-only access is // theoretically possible Files.delete(file); return FileVisitResult.CONTINUE; } @Override public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException { if (exc == null) { Files.delete(dir); return FileVisitResult.CONTINUE; } else { // directory iteration failed; propagate exception throw exc; } } }); } }
DBUpdateAndRollback.java
import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; import java.sql.Statement; public class DBUpdateAndRollback { public static void Sample1(String myField, String condition1, String condition2) throws SQLException { Connection connection = DriverManager.getConnection("jdbc:postgresql://localhost/test", "user", "password"); connection.setAutoCommit(false); PreparedStatement ps = connection.prepareStatement("UPDATE myTable SET myField = ? WHERE myOtherField1 = ? AND myOtherField2 = ?"); ps.setString(1, myField); ps.setString(2, condition1); ps.setString(3, condition2); // If more than 10 entries change, panic and rollback int numChanged = ps.executeUpdate(); if(numChanged > 10) { connection.rollback(); } else { connection.commit(); } ps.close(); connection.close(); } public static void Sample2(String myField, String condition1, String condition2) throws SQLException { Connection connection = DriverManager.getConnection("jdbc:postgresql://localhost/test", "user", "password"); connection.setAutoCommit(false); Statement st = connection.createStatement(); String sql = "UPDATE myTable SET myField = '" + myField + "' WHERE myOtherField1 = '" + condition1 + "' AND myOtherField2 = '" + condition2 + "'"; int numChanged = st.executeUpdate(sql); // If more than 10 entries change, panic and rollback if(numChanged > 10) { connection.rollback(); } else { connection.commit(); } st.close(); connection.close(); } }
DownloadWebpage.java
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.zip.GZIPInputStream; import java.util.zip.InflaterInputStream; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.HttpClientBuilder; public class DownloadWebpageSamples { public static String downloadWebpage1(String address) throws MalformedURLException, IOException { URL url = new URL(address); BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream())); String line; String page = ""; while((line = br.readLine()) != null) { page += line + "\n"; } br.close(); return page; } public static String downloadWebpage2(String address) throws MalformedURLException, IOException { URL url = new URL(address); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); HttpURLConnection.setFollowRedirects(true); String encoding = conn.getContentEncoding(); InputStream is = null; if(encoding != null && encoding.equalsIgnoreCase("gzip")) { is = new GZIPInputStream(conn.getInputStream()); } else if (encoding != null && encoding.equalsIgnoreCase("deflate")) { is = new InflaterInputStream(conn.getInputStream()); } else { is = conn.getInputStream(); } BufferedReader br = new BufferedReader(new InputStreamReader(is)); String line; String page = ""; while((line = br.readLine()) != null) { page += line + "\n"; } br.close(); return page; } public static String downloadWebpage3(String address) throws ClientProtocolException, IOException { HttpClient client = HttpClientBuilder.create().build(); HttpGet request = new HttpGet(address); HttpResponse response = client.execute(request); BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent())); String line; String page = ""; while((line = br.readLine()) != null) { page += line + "\n"; } br.close(); return page; } }
EncryptFile.java
import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import javax.crypto.Cipher; import javax.crypto.CipherOutputStream; import javax.crypto.NoSuchPaddingException; import javax.crypto.SecretKey; public class EncryptFile { public static void encryptFile(File in, File out, SecretKey key) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IOException { // Create Cipher for Algorithm using Encryption Key Cipher c = Cipher.getInstance("AES"); c.init(Cipher.ENCRYPT_MODE, key); // Create File Read/Writers FileInputStream fin = new FileInputStream(in); FileOutputStream fout = new FileOutputStream(out); // Create Cipher Output Stream CipherOutputStream cout = new CipherOutputStream(fout, c); // Read input writer and write encrypted version using cipher stream int i; byte[] data = new byte[1024]; while((i = fin.read(data)) != -1) cout.write(data, 0, i); // Clean-up fin.close(); cout.close(); } }
ExecuteExternalProcessAndReadInput.java
import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStreamReader; import java.lang.ProcessBuilder.Redirect; import java.util.Map; public class ExecuteExternalProcessAndReadInput { // start AND ProcessBuilder AND (redirect)|(getInputStream|getOutputStream) public static void execute1() throws IOException, InterruptedException { //Create Process Builder with Command and Arguments ProcessBuilder pb = new ProcessBuilder("myCommand", "myArg1", "myArg2"); //Setup Execution Environment Map<String, String> env = pb.environment(); env.put("VAR1", "myValue"); env.remove("OTHERVAR"); env.put("VAR2", env.get("VAR1") + "suffix"); //Setup execution directory pb.directory(new File("myDir")); //Handle Output Streams File log = new File("log"); pb.redirectErrorStream(true); pb.redirectOutput(Redirect.appendTo(log)); // Start Process Process p = pb.start(); //Wait for process to complete p.waitFor(); //Cleanup p.destroy(); } // exec AND (getInputStream)|(getErrorStream) public static void execute2() throws IOException, InterruptedException { // Get Runtime Runtime rt = Runtime.getRuntime(); //Execute Process Process p = rt.exec("myCommand"); //Redirect external process stdout to this program's stdout BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream())); String line = null; while((line = in.readLine()) != null) System.out.println(line); //Wait for process to complete and cleanup p.waitFor(); p.destroy(); } }
ExtactUsingRegex.java
import java.util.LinkedList; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern; public class ExtactUsingRegex { // find AND start AND end AND compile AND matcher public static List<String> extractMatches(String text, String pattern) { List<String> matches = new LinkedList<String>(); Pattern p = Pattern.compile(pattern); Matcher m = p.matcher(text); while(m.find()) { matches.add(text.subSequence(m.start(), m.end()).toString()); } return matches; } //while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*\.\s*find\s*\( //[a-z,A-Z,0-9,_,$]+\s*\.\s*start\s*\( //[a-z,A-Z,0-9,_,$]+\s*\.\s*end\s*\( //[a-z,A-Z,0-9,_,$]+\s*\.\s*compile\s*\( //[a-z,A-Z,0-9,_,$]+\s*\.\s*matcher\s*\( }
Fibonacci.java
public class Fibonacci { public static int getFibonacci(int n) { if(n == 0) return 0; else if (n == 1) return 1; else return getFibonacci(n-1) + getFibonacci(n-2); } }
FileChooser.java
import java.io.File; import javax.swing.JFileChooser; import javax.swing.JFrame; public class FileChooser { public static File chooseFileOpen(JFrame frame) { File retval; //Create and configure file chooser JFileChooser fc = new JFileChooser(); fc.setDialogTitle("Select input file."); fc.setFileSelectionMode(JFileChooser.FILES_ONLY); fc.setMultiSelectionEnabled(false); //Show dialog and wait for user input int status = fc.showOpenDialog(frame); //React to input if(status == JFileChooser.APPROVE_OPTION) { retval = fc.getSelectedFile(); } else if (status == JFileChooser.CANCEL_OPTION) { retval = null; } else { retval = null; } //Cleanup fc.setEnabled(false); fc.setVisible(false); //Return return retval; } public static File chooseFileSave(JFrame frame) { File retval; //Create and configure file chooser JFileChooser fc = new JFileChooser(); fc.setDialogTitle("Select input file."); fc.setFileSelectionMode(JFileChooser.FILES_ONLY); fc.setMultiSelectionEnabled(false); //Show dialog and wait for user input int status = fc.showSaveDialog(frame); //React to input if(status == JFileChooser.APPROVE_OPTION) { retval = fc.getSelectedFile(); } else if (status == JFileChooser.CANCEL_OPTION) { retval = null; } else { retval = null; } //Cleanup fc.setEnabled(false); fc.setVisible(false); //Return return retval; } public static File[] chooseFileOpenMultiple(JFrame frame) { File retval[]; //Create and configure file chooser JFileChooser fc = new JFileChooser(); fc.setDialogTitle("Select input file."); fc.setFileSelectionMode(JFileChooser.FILES_ONLY); fc.setMultiSelectionEnabled(true); //Show dialog and wait for user input int status = fc.showSaveDialog(frame); //React to input if(status == JFileChooser.APPROVE_OPTION) { retval = fc.getSelectedFiles(); } else if (status == JFileChooser.CANCEL_OPTION) { retval = null; } else { retval = null; } //Cleanup fc.setEnabled(false); fc.setVisible(false); //Return return retval; } public static File[] chooseFileDirectory(JFrame frame) { File retval[]; //Create and configure file chooser JFileChooser fc = new JFileChooser(); fc.setDialogTitle("Select input file."); fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY); fc.setMultiSelectionEnabled(false); //Show dialog and wait for user input int status = fc.showSaveDialog(frame); //React to input if(status == JFileChooser.APPROVE_OPTION) { retval = fc.getSelectedFiles(); } else if (status == JFileChooser.CANCEL_OPTION) { retval = null; } else { retval = null; } //Cleanup fc.setEnabled(false); fc.setVisible(false); //Return return retval; } //public static void main(String args[]) { // JFrame frame = new JFrame(); // frame.setVisible(true); // System.out.println(FileChooser.chooseFileOpen(frame)); // System.out.println(FileChooser.chooseFileSave(frame)); // System.out.println(FileChooser.chooseFileOpenMultiple(frame)); // frame.setVisible(false); // frame.disable(); //} }
FTP_ApacheCommonsNet_Samples.java
import java.io.IOException; import java.net.SocketException; import org.apache.commons.net.ftp.FTPClient; import org.apache.commons.net.ftp.FTPHTTPClient; import org.apache.commons.net.ftp.FTPSClient; public class FTP_ApacheCommonsNet_Samples { public FTPClient sample1a(String server, int port, String username, String password) throws SocketException, IOException { FTPClient ftpClient = new FTPClient(); ftpClient.connect(server, port); ftpClient.login(username, password); return ftpClient; } public FTPClient sample1b(String server, String username, String password) throws SocketException, IOException { FTPClient ftpClient = new FTPClient(); ftpClient.connect(server); ftpClient.login(username, password); return ftpClient; } public FTPClient sample1c(String server, int port, String username, String password) throws SocketException, IOException { FTPClient ftpClient = new FTPClient(); ftpClient.setDefaultPort(port); ftpClient.connect(server); ftpClient.login(username, password); return ftpClient; } public FTPClient sample2a(String server, int port, String username, String password) throws SocketException, IOException { FTPSClient ftpClient = new FTPSClient(); ftpClient.connect(server, port); ftpClient.login(username, password); return ftpClient; } public FTPClient sample2b(String server, String username, String password) throws SocketException, IOException { FTPSClient ftpClient = new FTPSClient(); ftpClient.connect(server); ftpClient.login(username, password); return ftpClient; } public FTPClient sample2c(String server, int port, String username, String password) throws SocketException, IOException { FTPSClient ftpClient = new FTPSClient(); ftpClient.setDefaultPort(port); ftpClient.connect(server); ftpClient.login(username, password); return ftpClient; } public FTPClient sample3a(String ftpserver, int ftpport, String proxyserver, int proxyport, String username, String password) throws SocketException, IOException { FTPHTTPClient ftpClient = new FTPHTTPClient(proxyserver, proxyport); ftpClient.connect(ftpserver, ftpport); ftpClient.login(username, password); return ftpClient; } public FTPClient sample3b(String ftpserver, String proxyserver, int proxyport, String username, String password) throws SocketException, IOException { FTPHTTPClient ftpClient = new FTPHTTPClient(proxyserver, proxyport); ftpClient.connect(ftpserver); ftpClient.login(username, password); return ftpClient; } public FTPClient sample3c(String ftpserver, int ftpport, String proxyserver, int proxyport, String username, String password) throws SocketException, IOException { FTPHTTPClient ftpClient = new FTPHTTPClient(proxyserver, proxyport); ftpClient.setDefaultPort(ftpport); ftpClient.connect(ftpserver); ftpClient.login(username, password); return ftpClient; } }
FTP_FTP4J_Samples.java
import it.sauronsoftware.ftp4j.FTPAbortedException; import it.sauronsoftware.ftp4j.FTPClient; import it.sauronsoftware.ftp4j.FTPDataTransferException; import it.sauronsoftware.ftp4j.FTPException; import it.sauronsoftware.ftp4j.FTPFile; import it.sauronsoftware.ftp4j.FTPIllegalReplyException; import it.sauronsoftware.ftp4j.FTPListParseException; import java.io.IOException; public class FTP_FTP4J_Samples { public FTPClient sample1(String server, int port, String username, String password) throws IllegalStateException, IOException, FTPIllegalReplyException, FTPException { FTPClient ftpClient = new FTPClient(); ftpClient.connect(server, port); ftpClient.login(username, password); return ftpClient; } public FTPClient sample2(String server, String username, String password) throws IllegalStateException, IOException, FTPIllegalReplyException, FTPException { FTPClient ftpClient = new FTPClient(); ftpClient.connect(server); ftpClient.login(username, password); return ftpClient; } }
GCD.java
//Heuristic: //((while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*0\s*\).*[a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*%\s*[a-z,A-Z,0-9,_,$]+)|(while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*[a-z,A-Z,0-9,_,$]+\s*\).*[a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*-\s*[a-z,A-Z,0-9,_,$]+)|(return\s+[a-z,A-Z,0-9,_,$]+\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*,\s*[a-z,A-Z,0-9,_,$]+\s*%\s*[a-z,A-Z,0-9,_,$]+\))) public class GCD { // while(b != 0) AND b = a % b // while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*0\s*\) // [a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*%\s*[a-z,A-Z,0-9,_,$]+ // while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*0\s*\).*[a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*%\s*[a-z,A-Z,0-9,_,$]+ public static int gcd1(int a, int b) { while (b != 0) { int t = b; b = a % b; a = t; } return a; } // while(a != b) AND a = a - b //while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*[a-z,A-Z,0-9,_,$]+\s*\) //[a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*-\s*[a-z,A-Z,0-9,_,$]+ //while\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*!=\s*[a-z,A-Z,0-9,_,$]+\s*\).*[a-z,A-Z,0-9,_,$]+\s*=\s*[a-z,A-Z,0-9,_,$]+\s*-\s*[a-z,A-Z,0-9,_,$]+ public static int gcd2(int a, int b) { while (a != b) { if (a > b) a = a - b; else b = b - a; } return a; } // return gcd3(b, a % b) //return\s+[a-z,A-Z,0-9,_,$]+\s*\(\s*[a-z,A-Z,0-9,_,$]+\s*,\s*[a-z,A-Z,0-9,_,$]+\s*%\s*[a-z,A-Z,0-9,_,$]+\) public static int gcd3(int a, int b) { if (b == 0) { return 1; } else { return gcd3(b, a % b); } } }
getMACAddresInStandardForm.java
import java.net.InetAddress; import java.net.NetworkInterface; import java.net.SocketException; import java.net.UnknownHostException; public class getMACAddresInStandardForm { public static String getMyMacAddress1() throws SocketException, UnknownHostException { InetAddress ip = InetAddress.getByName("192.168.0.12"); System.out.println(ip.getHostAddress()); NetworkInterface network = NetworkInterface.getByInetAddress(ip); byte[] mac = network.getHardwareAddress(); String macStr = ""; for(int i = 0; i < mac.length; i++) { int a = mac [i] & 0xFF; if (a > 15) macStr += Integer.toHexString (a); else macStr += "0" + Integer.toHexString (a); if (i < (mac.length - 1)) { macStr += "-"; } } return macStr; } public static String getMyMacAddress2() throws SocketException, UnknownHostException { InetAddress ip = InetAddress.getByName("192.168.0.12"); System.out.println(ip.getHostAddress()); NetworkInterface network = NetworkInterface.getByInetAddress(ip); byte[] mac = network.getHardwareAddress(); StringBuilder sb = new StringBuilder(); for (int i = 0; i < mac.length; i++) { sb.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : "")); } String macStr = sb.toString(); return macStr; } //public static void main(String args[]) throws SocketException, UnknownHostException { // System.out.println(getMACAddresInStandardForm.getMyMacAddress2()); //} }
InstantiateNamedClassUsingReflection.java
import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; public class InstantiateNamedClassUsingReflection { public static Object instantiate(String clazz, Object[] pvalues, Class[] ptypes) throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { Class<?> c = Class.forName(clazz); Constructor<?> constructor = c.getConstructor(ptypes); Object obj = constructor.newInstance(pvalues); return obj; } }
LoadFileIntoByteArray.java
import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; public class LoadFileIntoByteArray { public static byte[] loadFile(File file) throws Exception { if (!file.exists() || !file.canRead()) { String message = "Cannot read file: " + file.getCanonicalPath(); throw new Exception(message); } FileInputStream fis = new FileInputStream(file); ByteArrayOutputStream data = new ByteArrayOutputStream(); int len = 0; byte[] buf = new byte[1024]; while ((len = fis.read(buf)) >= 0) { data.write(buf, 0, len); } fis.close(); byte[] retval = data.toByteArray(); data.close(); return retval; } }
LoadFont.java
import java.awt.Font; import java.awt.FontFormatException; import java.awt.GraphicsEnvironment; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.net.URL; //HEURISTIC: createFont AND registerFont // 1 - Create the font. 2 - Register the font with the graphics environemnt. public class LoadFont { public static void loadFont1(URL url) throws FontFormatException, IOException { InputStream stream = url.openStream(); Font font = Font.createFont(Font.TRUETYPE_FONT, stream); GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); ge.registerFont(font); } public static void loadFont2(File file) throws FontFormatException, IOException { FileInputStream stream = new FileInputStream(file); Font font = Font.createFont(Font.TYPE1_FONT, stream); GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); ge.registerFont(font); } public static void loadFont3(File file) throws FontFormatException, IOException { Font font = Font.createFont(Font.TRUETYPE_FONT, file); GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); ge.registerFont(font); } }
MD5.java
public class MD5_Target { public String getMD5(String password) throws NoSuchAlgorithmException { MessageDigest md = MessageDigest.getInstance("MD5"); md.update(password.getBytes()); byte byteData[] = md.digest(); StringBuffer sb = new StringBuffer(); for(int i = 0; i < byteData.length; i++) { sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1)); } return sb.toString(); } }
OpenFileInDesktopApp.java
import java.awt.Desktop; import java.io.File; import java.io.IOException; public class OpenFileInDesktopApp { public static void openFileInDesktopApp(File file) throws IOException { Desktop desktop = Desktop.getDesktop(); if(Desktop.isDesktopSupported()) { desktop.open(file); } else { throw new UnsupportedOperationException("Not supported on this platform."); } } }
OpenURLInSystemBrowser.java
import java.awt.Desktop; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; public class OpenURLInSystemBrowser { public static void openURL(URI uri) throws IOException, URISyntaxException { if(Desktop.isDesktopSupported()) { Desktop desktop = Desktop.getDesktop(); desktop.browse(uri); } else { throw new UnsupportedOperationException("Desktop is not supported on this platform."); } } }
ParseCSVFile.java
package database; import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; import java.util.StringTokenizer; public class ParseCSVFile { // c AND , public static void parseCSV(File file) throws IOException { StringTokenizer toks; BufferedReader in = new BufferedReader(new FileReader(file)); String line; int lnum = 0; while((line = in.readLine()) != null) { lnum++; toks = new StringTokenizer(line, ","); int tnum = 0; while(toks.hasMoreTokens()) { tnum++; System.out.println("Line# " + lnum + " Token# " + tnum + ": " + toks.nextToken()); } } in.close(); } }
ParseXML2Dom.java
import java.io.File; import java.io.IOException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; public class ParseXML2Dom { //Heuristic: newDocumentBuilder AND parse public static Document parse(File xmlFile) throws ParserConfigurationException, SAXException, IOException { // Create DocumentBuilderFactory DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance(); // Configure Factory (this step will vary largely) docFactory.setValidating(false); docFactory.setNamespaceAware(true); docFactory.setExpandEntityReferences(false); // Use Factory to Build Document Builder (i.e., configured XML parser) DocumentBuilder parser = docFactory.newDocumentBuilder(); //Parse the Document Document document = parser.parse(xmlFile); //Return the Document return document; } public static void main(String args[]) throws ParserConfigurationException, SAXException, IOException { Document document = ParseXML2Dom.parse(new File("/home/jeff/test.xml")); NodeList nodeList = document.getElementsByTagName("*"); for (int i = 0; i < nodeList.getLength(); i++) { Node node = nodeList.item(i); if (node.getNodeType() == Node.ELEMENT_NODE) { // do something with the current element System.out.println(node.getNodeName()); System.out.println(node.getTextContent()); } } } }
PlaySound.java
import java.io.File; import java.io.IOException; import java.net.MalformedURLException; import javax.sound.sampled.AudioFormat; import javax.sound.sampled.AudioInputStream; import javax.sound.sampled.AudioSystem; import javax.sound.sampled.Clip; import javax.sound.sampled.DataLine; import javax.sound.sampled.LineUnavailableException; import javax.sound.sampled.SourceDataLine; import javax.sound.sampled.UnsupportedAudioFileException; public class PlaySound { //Heuristic: getClip, open, start public static void playSound1(File file) throws LineUnavailableException, UnsupportedAudioFileException, IOException { Clip clip = AudioSystem.getClip(); AudioInputStream inputStream = AudioSystem.getAudioInputStream(file); clip.open(inputStream); clip.start(); } //getLine, read, write, getAudioInputStream public static void playSound2(File file) throws UnsupportedAudioFileException, IOException, LineUnavailableException { AudioInputStream inputStream = AudioSystem.getAudioInputStream(file); AudioFormat audioFormat = inputStream.getFormat(); DataLine.Info info = new DataLine.Info(SourceDataLine.class, audioFormat); SourceDataLine sourceLine = (SourceDataLine) AudioSystem.getLine(info); sourceLine.open(audioFormat); sourceLine.start(); int nbytes = 0; byte[] data = new byte[1024]; while(nbytes != -1) { nbytes = inputStream.read(data, 0, data.length); sourceLine.write(data, 0, data.length); } sourceLine.drain(); sourceLine.close(); } public static void main(String args[]) throws MalformedURLException, LineUnavailableException, UnsupportedAudioFileException, IOException { //PlaySound.playSound1(new File("/Users/jeff/Downloads/11k16bitpcm.wav")); PlaySound.playSound2(new File("/Users/jeff/Downloads/11k16bitpcm.wav")); //while(true); } }
PrimeFactors.java
import java.util.ArrayList; import java.util.List; public class PrimeFactors { public static List<Integer> primeFactors1(int number) { int n = number; List<Integer> factors = new ArrayList<Integer>(); for (int i = 2; i <= n; i++) { while (n % i == 0) { factors.add(i); n /= i; } } return factors; } public static List<Integer> primeFactors2(int number) { int n = number; List<Integer> factors = new ArrayList<Integer>(); for (int i = 2; i <= n; i++) { while (n % i == 0) { factors.add(i); n /= i; } } return factors; } //public static void main(String args[]) { // int i = 998; // System.out.println(primeFactors1(i)); // System.out.println(primeFactors2(i)); //} }
ResizeObjectArray.java
public class ResizeObjectArray { public static Object[] resizeArray(Object[] oldArray, int newSize) { //implementation for any object type int oldSize = oldArray.length; Class<?> elementType = oldArray.getClass().getComponentType(); Object newArray = java.lang.reflect.Array.newInstance(elementType, newSize); int preserveLength = Math.min(oldSize, newSize); if (preserveLength > 0) { System.arraycopy(oldArray, 0, newArray, 0, preserveLength); } return (Object[]) newArray; } }
ScreenShot.java
import java.awt.AWTException; import java.awt.Dimension; import java.awt.Rectangle; import java.awt.Robot; import java.awt.Toolkit; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import javax.imageio.ImageIO; public class ScreenShot { //createScreenCapture public static void screenshot(File file) throws AWTException, IOException { Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); Rectangle screenRectangle = new Rectangle(screenSize); Robot robot = new Robot(); BufferedImage image = robot.createScreenCapture(screenRectangle); ImageIO.write(image, "png", file); } }
SendEMail.java
//FROM :http://www.mkyong.com/java/javamail-api-sending-email-via-gmail-smtp-example/ //Copyright © 2008-2014 Mkyong.com, all rights reserved. import java.util.Properties; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; public class SendMailTLS { public static void main(String[] args) { final String username = "[email protected]"; final String password = "password"; Properties props = new Properties(); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.starttls.enable", "true"); props.put("mail.smtp.host", "smtp.gmail.com"); props.put("mail.smtp.port", "587"); Session session = Session.getInstance(props, new javax.mail.Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(username, password); } }); try { Message message = new MimeMessage(session); message.setFrom(new InternetAddress("[email protected]")); message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected]")); message.setSubject("Testing Subject"); message.setText("Dear Mail Crawler," + "\n\n No spam to my email, please!"); Transport.send(message); } catch (MessagingException e) { throw new RuntimeException(e); } } }
SetUpGraphicalViewerSelectionEventHandler.java
public class SetUpGraphicalViewerSelectionEventHandler { public void setup() { final GraphicalViewer viewer = new ScrollingGraphicalViewer(); viewer.addSelectionChangedListener(new ISelectionChangedListener() { public void selectionChanged(SelectionChangedEvent event) { } }); } }
SetUpScrollingGraphicalViewer.java
public class SetUpScrollingGraphicalViewer { public void createPartControl(Model model) { GraphicalViewer viewer = new ScrollingGraphicalViewer(); viewer.setContents(model); } }
ShuffleArrayInPlace.java
import java.util.Random; public class ShuffleArrayInPlace { // Heuristic // Need to swap: // a[i] = a[j] AND a[j] = tmp // Need a random index: // random.nextInt( // #1: // j = i + random.nextInt(length-i); // #2: // j = random.nextInt(i+1); public static void shuffle1(int[] a) { //Standard Fisher-Yates/Knuth Shuffle int length = a.length; Random random = new Random(); random.nextInt(); for(int i = 0; i < length; i++) { //Chose index to swap with from i <= j < length int j = i + random.nextInt(length-i); //Swap int tmp = a[i]; a[i] = a[j]; a[j] = tmp; } } public static void shuffle2(int[] a) { //Alternate Fisher-Yates/Knuth Shuffle Random random = new Random(); random.nextInt(); for(int i = a.length-1; i >= 1; i--) { //Choose index to swap from 0 <= j <= i int j = random.nextInt(i+1); //Swap int tmp = a[i]; a[i] = a[j]; a[j] = tmp; } } public static <T> void shuffle3(T[] a) { //Standard Fisher-Yates/Knuth Shuffle for Object array int length = a.length; Random random = new Random(); random.nextInt(); for(int i = 0; i < length; i++) { //Chose index to swap with from i <= j < length int j = i + random.nextInt(length-i); //Swap T tmp = a[i]; a[i] = a[j]; a[j] = tmp; } } //public static void main(String args[]) { // int arr[] = {1,2,3,4,5,6,7,8,9,10}; // shuffle1(arr); // for(int i : arr) { // System.out.print(i + " " ); // } // System.out.println(); // shuffle2(arr); // for(int i : arr) { // System.out.print(i + " " ); // } // System.out.println(); // Integer arro[] = {1,2,3,4,5,6,7,8,9,10}; // shuffle3(arro); // for(int i : arro) { // System.out.print(i + " " ); // } //} }
TestPalindrome.java
public class Plaindrome { public static boolean isPalindrome(String original) { //A not very efficient example String reverse = ""; int length = original.length(); for (int i = length - 1; i >= 0; i--) reverse = reverse + original.charAt(i); if (original.equals(reverse)) return true; else return false; } }
TransposeMatrix.java
package database; public class TransposeMatrix { public static int[][] transpose(int[][] m) { int[][] retval = new int[m[0].length][m.length]; for(int i = 0; i < m.length; i++) { for(int j = 0; j < m[0].length; j++) { retval[j][i] = m[i][j]; } } return retval; } // public static void print(int[][] m) { // for(int i = 0; i < m.length; i++) { // for(int j = 0; j < m[0].length; j++) { // System.out.println("m[" + (i+1) + "][" + (j+1) + "]=" + m[i][j]); // } // } // } // public static void main(String args[]) { // int[][] om = new int[2][3]; // om[0][0] = 11; // om[0][1] = 12; // om[0][2] = 13; // om[1][0] = 21; // om[1][1] = 22; // om[1][2] = 23; // System.out.println(om.length); // System.out.println(om[0].length); // System.out.println("---"); // TransposeMatrix.print(om); // System.out.println("---"); // TransposeMatrix.print(TransposeMatrix.transpose(om)); // } }
UnZip.java
public class UnZip { public static void unzip1(File zipfile, File outputdir) throws IOException { //Buffer for copying the files out of the zip input stream byte[] buffer = new byte[1024]; //Create parent output directory if it doesn't exist if(!outputdir.exists()) { outputdir.mkdirs(); } //Create the zip input stream //OR ArchiveInputStream zis = new ArchiveStreamFactory().createArchiveInputStream(ArchiveStreamFactory.ZIP, new FileInputStream(zipfile)); ArchiveInputStream zis = new ZipArchiveInputStream(new FileInputStream(zipfile)); //Iterate through the entries of the zip file, and extract them to the output directory ArchiveEntry ae = zis.getNextEntry(); // OR zis.getNextZipEntry() while(ae != null) { //Resolve new file File newFile = new File(outputdir + File.separator + ae.getName()); //Create parent directories if not exists if(!newFile.getParentFile().exists()) newFile.getParentFile().mkdirs(); if(ae.isDirectory()) { //If directory, create if not exists if(!newFile.exists()) newFile.mkdir(); } else { //If file, write file FileOutputStream fos = new FileOutputStream(newFile); int len; while((len = zis.read(buffer)) > 0) { fos.write(buffer, 0, len); } fos.close(); } //Proceed to the next entry in the zip file ae = zis.getNextEntry(); } //Cleanup zis.close(); } public static void unzip2(File zipfile, File outputdir) throws IOException { //Buffer for extracting files byte[] buffer = new byte[1024]; //Zip file ZipFile zip = new ZipFile(zipfile); //Get entries Enumeration<ZipArchiveEntry> files = zip.getEntries(); //Iterate through the entries while(files.hasMoreElements()) { //Get entry ZipArchiveEntry ze = files.nextElement(); //Resolve entry file File newFile = new File(outputdir + File.separator + ze.getName()); //Make parent directories newFile.getParentFile().mkdirs(); if(ze.isDirectory()) { //If directory, create it newFile.mkdir(); } else { //If file, extract it InputStream is = zip.getInputStream(ze); FileOutputStream fos = new FileOutputStream(newFile); int len; while((len = is.read(buffer)) > 0) { fos.write(buffer, 0, len); } fos.close(); is.close(); } } //Cleanup zip.close(); } }
WritePDF.java
import com.itextpdf.text.Document; import com.itextpdf.text.DocumentException; import com.itextpdf.text.Paragraph; import com.itextpdf.text.pdf.PdfWriter; import java.io.FileOutputStream; import java.io.FileNotFoundException; /** http://tutorials.jenkov.com/java-itext/getting-started.html */ public class WritePDF { public static void main(String[] args) { Document document = new Document(); try { PdfWriter.getInstance(document, new FileOutputStream("HelloWorld.pdf")); document.open(); document.add(new Paragraph("A Hello World PDF document.")); document.close(); // no need to close PDFwriter? } catch (DocumentException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } } }
XMPPSendMessage.java
import com.google.appengine.api.xmpp.JID; import com.google.appengine.api.xmpp.Message; import com.google.appengine.api.xmpp.MessageBuilder; import com.google.appengine.api.xmpp.SendResponse; import com.google.appengine.api.xmpp.XMPPService; import com.google.appengine.api.xmpp.XMPPServiceFactory; public class XMPPSendMessage { public static boolean sendMessage(String message, String receipient) { //Create Message JID jid = new JID(receipient); Message msg = new MessageBuilder() .withRecipientJids(jid) .withBody(message) .build(); //Send Message XMPPService xmpp = XMPPServiceFactory.getXMPPService(); SendResponse status = xmpp.sendMessage(msg); //Get and return if successful boolean messageSent = false; messageSent = (status.getStatusMap().get(jid) == SendResponse.Status.SUCCESS); return messaageSent; } }
ZipFiles.java
import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.util.zip.ZipEntry; import java.util.zip.ZipOutputStream; public class ZipFiles { public static void ZipFiles(File zipfile, File[] files) throws IOException { byte[] buffer = new byte[1024]; FileOutputStream fos = new FileOutputStream(zipfile); ZipOutputStream zos = new ZipOutputStream(fos); // For Each File for(int i = 0; i < files.length; i++) { // Open File File src = files[i]; FileInputStream fis = new FileInputStream(src); //Create new zip entry ZipEntry entry = new ZipEntry(src.getName()); zos.putNextEntry(entry); //Write the file to the entry in the zip file (compressed) int length; while((length = fis.read(buffer)) > 0) { zos.write(buffer, 0, length); } zos.closeEntry(); //Close Original File fis.close(); } // Close Zip File zos.close(); } // public static void main(String args[]) throws IOException { // File[] files = {new File("/media/jeff/ssd/test1"), new File("/media/jeff/ssd/test2")}; // ZipFiles.ZipFiles(new File("/media/jeff/ssd/zip.zip"), files); // } }
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