Convert utility classes to interface

src/main/java/com/hierynomus/sshj/secg/SecgUtils.java

@@ -22,11 +22,11 @@
 import java.security.spec.EllipticCurve;
 import java.util.Arrays;
 
-public class SecgUtils {
+public interface SecgUtils {
     /**
      * SECG 2.3.4 Octet String to ECPoint
      */
-    public static ECPoint getDecoded(byte[] M, EllipticCurve curve) {
+    static ECPoint getDecoded(byte[] M, EllipticCurve curve) {
         int elementSize = getElementSize(curve);
         if (M.length != 2 * elementSize + 1 || M[0] != 0x04) {
             throw new SSHRuntimeException("Invalid 'f' for Elliptic Curve " + curve.toString());
@@ -41,7 +41,7 @@ public static ECPoint getDecoded(byte[] M, EllipticCurve curve) {
     /**
      * SECG 2.3.3 ECPoint to Octet String
      */
-    public static byte[] getEncoded(ECPoint point, EllipticCurve curve) {
+    static byte[] getEncoded(ECPoint point, EllipticCurve curve) {
         int elementSize = getElementSize(curve);
         byte[] M = new byte[2 * elementSize + 1];
         M[0] = 0x04;
@@ -53,7 +53,7 @@ public static byte[] getEncoded(ECPoint point, EllipticCurve curve) {
         return M;
     }
 
-    private static byte[] stripLeadingZeroes(byte[] bytes) {
+    static byte[] stripLeadingZeroes(byte[] bytes) {
         int start = 0;
         while (bytes[start] == 0x0) {
             start++;
@@ -62,7 +62,7 @@ private static byte[] stripLeadingZeroes(byte[] bytes) {
         return Arrays.copyOfRange(bytes, start, bytes.length);
     }
 
-    private static int getElementSize(EllipticCurve curve) {
+    static int getElementSize(EllipticCurve curve) {
         int fieldSize = curve.getField().getFieldSize();
         return (fieldSize + 7) / 8;
     }

src/main/java/com/hierynomus/sshj/userauth/keyprovider/OpenSSHKeyFileUtil.java

@@ -26,11 +26,9 @@
 import java.io.Reader;
 import java.security.PublicKey;
 
-public class OpenSSHKeyFileUtil {
-    private OpenSSHKeyFileUtil() {
-    }
+public interface OpenSSHKeyFileUtil {
 
-    public static File getPublicKeyFile(File privateKeyFile) {
+    static File getPublicKeyFile(File privateKeyFile) {
         File pubKey = new File(privateKeyFile + "-cert.pub");
         if (!pubKey.exists()) {
             pubKey = new File(privateKeyFile + ".pub");
@@ -46,7 +44,7 @@ public static File getPublicKeyFile(File privateKeyFile) {
      *
      * @param publicKey Public key accessible through a {@code Reader}
      */
-    public static ParsedPubKey initPubKey(Reader publicKey) throws IOException {
+    static ParsedPubKey initPubKey(Reader publicKey) throws IOException {
         try (BufferedReader br = new BufferedReader(publicKey)) {
             String keydata;
             while ((keydata = br.readLine()) != null) {
@@ -71,7 +69,7 @@ public static ParsedPubKey initPubKey(Reader publicKey) throws IOException {
     }
 
 
-    public static class ParsedPubKey {
+    class ParsedPubKey {
         private final KeyType type;
         private final PublicKey pubKey;
 

src/main/java/net/schmizz/concurrent/ErrorDeliveryUtil.java

@@ -17,24 +17,24 @@
 
 import java.util.Collection;
 
-public class ErrorDeliveryUtil {
+public interface ErrorDeliveryUtil {
 
-    public static void alertPromises(Throwable x, Promise<?, ?>... promises) {
+    static void alertPromises(Throwable x, Promise<?, ?>... promises) {
         for (Promise<?, ?> p : promises)
             p.deliverError(x);
     }
 
-    public static void alertPromises(Throwable x, Collection<? extends Promise<?, ?>> promises) {
+    static void alertPromises(Throwable x, Collection<? extends Promise<?, ?>> promises) {
         for (Promise<?, ?> p : promises)
             p.deliverError(x);
     }
 
-    public static void alertEvents(Throwable x, Event<?>... events) {
+    static void alertEvents(Throwable x, Event<?>... events) {
         for (Event<?> e : events)
             e.deliverError(x);
     }
 
-    public static void alertEvents(Throwable x, Collection<? extends Event<?>> events) {
+    static void alertEvents(Throwable x, Collection<? extends Event<?>> events) {
         for (Event<?> e : events)
             e.deliverError(x);
     }

src/main/java/net/schmizz/sshj/common/Base64Decoder.java

@@ -16,7 +16,6 @@
 
 package net.schmizz.sshj.common;
 
-import java.io.IOException;
 import java.util.Base64;
 
 /**
@@ -25,19 +24,17 @@
  *
  * <p>Please use this class instead of {@link java.util.Base64.Decoder}.</p>
  */
-public class Base64Decoder {
-    private Base64Decoder() {
-    }
+public interface Base64Decoder {
 
-    public static byte[] decode(byte[] source) throws Base64DecodingException {
+    static byte[] decode(byte[] source) throws Base64DecodingException {
         try {
             return Base64.getDecoder().decode(source);
         } catch (IllegalArgumentException err) {
             throw new Base64DecodingException(err);
         }
     }
 
-    public static byte[] decode(String src) throws Base64DecodingException {
+    static byte[] decode(String src) throws Base64DecodingException {
         try {
             return Base64.getDecoder().decode(src);
         } catch (IllegalArgumentException err) {

src/main/java/net/schmizz/sshj/common/ByteArrayUtils.java

@@ -22,9 +22,9 @@
 import java.util.Arrays;
 
 /** Utility functions for byte arrays. */
-public class ByteArrayUtils {
+public interface ByteArrayUtils {
 
-    final static char[] digits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+    char[] digits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
 
     /**
      * Check whether some part or whole of two byte arrays is equal, for <code>length</code> bytes starting at some
@@ -38,7 +38,7 @@ public class ByteArrayUtils {
      *
      * @return <code>true</code> or <code>false</code>
      */
-    public static boolean equals(byte[] a1, int a1Offset, byte[] a2, int a2Offset, int length) {
+    static boolean equals(byte[] a1, int a1Offset, byte[] a2, int a2Offset, int length) {
         if (a1.length < a1Offset + length || a2.length < a2Offset + length)
             return false;
         while (length-- > 0)
@@ -57,7 +57,7 @@ public static boolean equals(byte[] a1, int a1Offset, byte[] a2, int a2Offset, i
      *
      * @return hex string, each octet delimited by a space
      */
-    public static String printHex(byte[] array, int offset, int len) {
+    static String printHex(byte[] array, int offset, int len) {
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < len; i++) {
             byte b = array[offset + i];
@@ -76,7 +76,7 @@ public static String printHex(byte[] array, int offset, int len) {
      *
      * @return hex string
      */
-    public static String toHex(byte[] array) {
+    static String toHex(byte[] array) {
         return toHex(array, 0, array.length);
     }
 
@@ -90,7 +90,7 @@ public static String toHex(byte[] array) {
      *
      * @return hex string
      */
-    public static String toHex(byte[] array, int offset, int len) {
+    static String toHex(byte[] array, int offset, int len) {
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < len; i++) {
             byte b = array[offset + i];
@@ -101,7 +101,7 @@ public static String toHex(byte[] array, int offset, int len) {
     }
 
 
-    public static byte[] parseHex(String hex) {
+    static byte[] parseHex(String hex) {
         if (hex == null) {
             throw new IllegalArgumentException("Hex string is null");
         }
@@ -118,7 +118,7 @@ public static byte[] parseHex(String hex) {
         return result;
     }
 
-    private static int parseHexDigit(char c) {
+    static int parseHexDigit(char c) {
         if (c >= '0' && c <= '9') {
             return c - '0';
         }
@@ -140,7 +140,7 @@ private static int parseHexDigit(char c) {
      *
      * @return UTF-8 bytes of the string
      */
-    public static byte[] encodeSensitiveStringToUtf8(char[] str) {
+    static byte[] encodeSensitiveStringToUtf8(char[] str) {
         CharsetEncoder charsetEncoder = StandardCharsets.UTF_8.newEncoder();
         ByteBuffer utf8Buffer = ByteBuffer.allocate((int) (str.length * charsetEncoder.maxBytesPerChar()));
         assert utf8Buffer.hasArray();

src/main/java/net/schmizz/sshj/common/ECDSAKeyFactory.java

@@ -33,11 +33,7 @@
 /**
  * Factory for generating Elliptic Curve Keys using Java Security components for NIST Curves
  */
-public class ECDSAKeyFactory {
-
-    private ECDSAKeyFactory() {
-
-    }
+public interface ECDSAKeyFactory {
 
     /**
      * Get Elliptic Curve Private Key for private key value and Curve Name
@@ -47,7 +43,7 @@ private ECDSAKeyFactory() {
      * @return Elliptic Curve Private Key
      * @throws GeneralSecurityException Thrown on failure to create parameter specification
      */
-    public static PrivateKey getPrivateKey(final BigInteger privateKeyInteger, final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
+    static PrivateKey getPrivateKey(final BigInteger privateKeyInteger, final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
         Objects.requireNonNull(privateKeyInteger, "Private Key integer required");
         Objects.requireNonNull(ecdsaCurve, "Curve required");
 
@@ -66,7 +62,7 @@ public static PrivateKey getPrivateKey(final BigInteger privateKeyInteger, final
      * @return Elliptic Curve Public Key
      * @throws GeneralSecurityException Thrown on failure to create parameter specification
      */
-    public static PublicKey getPublicKey(final ECPoint point, final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
+    static PublicKey getPublicKey(final ECPoint point, final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
         Objects.requireNonNull(point, "Elliptic Curve Point required");
         Objects.requireNonNull(ecdsaCurve, "Curve required");
 
@@ -77,7 +73,7 @@ public static PublicKey getPublicKey(final ECPoint point, final ECDSACurve ecdsa
         return keyFactory.generatePublic(publicKeySpec);
     }
 
-    private static ECParameterSpec getParameterSpec(final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
+    static ECParameterSpec getParameterSpec(final ECDSACurve ecdsaCurve) throws GeneralSecurityException {
         final ECGenParameterSpec genParameterSpec = new ECGenParameterSpec(ecdsaCurve.getCurveName());
         final AlgorithmParameters algorithmParameters = AlgorithmParameters.getInstance(KeyAlgorithm.EC_KEYSTORE);
         algorithmParameters.init(genParameterSpec);

src/main/java/net/schmizz/sshj/common/ErrorNotifiable.java

@@ -21,16 +21,16 @@
 public interface ErrorNotifiable {
 
     /** Utility functions. */
-    class Util {
+    interface Util {
 
         /** Notify all {@code notifiables} of given {@code error}. */
-        public static void alertAll(SSHException error, ErrorNotifiable... notifiables) {
+        static void alertAll(SSHException error, ErrorNotifiable... notifiables) {
             for (ErrorNotifiable notifiable : notifiables)
                 notifiable.notifyError(error);
         }
 
         /** Notify all {@code notifiables} of given {@code error}. */
-        public static void alertAll(SSHException error, Collection<? extends ErrorNotifiable> notifiables) {
+        static void alertAll(SSHException error, Collection<? extends ErrorNotifiable> notifiables) {
             for (ErrorNotifiable notifiable : notifiables)
                 notifiable.notifyError(error);
         }

src/main/java/net/schmizz/sshj/common/IOUtils.java

@@ -20,18 +20,18 @@
 import java.io.IOException;
 import java.io.InputStream;
 
-public class IOUtils {
+public interface IOUtils {
 
-    public static void closeQuietly(Closeable... closeables) {
+    static void closeQuietly(Closeable... closeables) {
         closeQuietly(LoggerFactory.DEFAULT, closeables);
     }
 
-    public static ByteArrayOutputStream readFully(InputStream stream)
+    static ByteArrayOutputStream readFully(InputStream stream)
             throws IOException {
         return readFully(stream, LoggerFactory.DEFAULT);
     }
 
-    public static void closeQuietly(LoggerFactory loggerFactory, Closeable... closeables) {
+    static void closeQuietly(LoggerFactory loggerFactory, Closeable... closeables) {
         for (Closeable c : closeables) {
             try {
                 if (c != null)
@@ -42,7 +42,7 @@ public static void closeQuietly(LoggerFactory loggerFactory, Closeable... closea
         }
     }
 
-    public static ByteArrayOutputStream readFully(InputStream stream, LoggerFactory loggerFactory)
+    static ByteArrayOutputStream readFully(InputStream stream, LoggerFactory loggerFactory)
             throws IOException {
         final ByteArrayOutputStream baos = new ByteArrayOutputStream();
         new StreamCopier(stream, baos, loggerFactory).copy();