BaseNCodecInputStream subclasses are now type-safe to match its matching

BaseNCodec

Author: garydgregory

src/changes/changes.xml

@@ -47,6 +47,7 @@ The <action> type attribute can be add,update,fix,remove.
       <!-- FIX -->
       <action type="update" dev="ggregory" due-to="Gary Gregory">Deprecate all but one Base32 constructor in favor of the builder added in version 1.17.0.</action>
       <action type="update" dev="ggregory" due-to="Gary Gregory">Deprecate all but one Base64 constructor in favor of the builder added in version 1.17.0.</action>
+      <action type="update" dev="ggregory" due-to="Gary Gregory">BaseNCodecInputStream subclasses are now type-safe to match its matching BaseNCodec.</action>
       <!-- ADD -->
       <action type="add" dev="ggregory" due-to="Fredrik Kjellberg, Gary Gregory">Add org.apache.commons.codec.digest.CRC16.</action>
       <!-- UPDATE -->

src/main/java/org/apache/commons/codec/binary/Base16InputStream.java

@@ -31,7 +31,7 @@
  * @see Base16
  * @since 1.15
  */
-public class Base16InputStream extends BaseNCodecInputStream {
+public class Base16InputStream extends BaseNCodecInputStream<Base16> {
 
     /**
      * Constructs a Base16InputStream such that all data read is Base16-decoded from the original provided InputStream.

src/main/java/org/apache/commons/codec/binary/Base32InputStream.java

@@ -54,7 +54,7 @@
  * @see <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a>
  * @since 1.5
  */
-public class Base32InputStream extends BaseNCodecInputStream {
+public class Base32InputStream extends BaseNCodecInputStream<Base32> {
 
     /**
      * Constructs a Base32InputStream such that all data read is Base32-decoded from the original provided InputStream.

src/main/java/org/apache/commons/codec/binary/Base64InputStream.java

@@ -58,7 +58,7 @@
  * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
  * @since 1.4
  */
-public class Base64InputStream extends BaseNCodecInputStream {
+public class Base64InputStream extends BaseNCodecInputStream<Base64> {
 
     /**
      * Constructs a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.

src/main/java/org/apache/commons/codec/binary/BaseNCodecInputStream.java

@@ -27,13 +27,17 @@
 import org.apache.commons.codec.binary.BaseNCodec.Context;
 
 /**
- * Abstract superclass for Base-N input streams.
+ * Abstracts Base-N input streams.
  *
+ * @param <T> A BaseNCodec subclass.
+ * @see Base16InputStream
+ * @see Base32InputStream
+ * @see Base64InputStream
  * @since 1.5
  */
-public class BaseNCodecInputStream extends FilterInputStream {
+public class BaseNCodecInputStream<T extends BaseNCodec> extends FilterInputStream {
 
-    private final BaseNCodec baseNCodec;
+    private final T baseNCodec;
 
     private final boolean doEncode;
 
@@ -50,7 +54,7 @@ public class BaseNCodecInputStream extends FilterInputStream {
      * @param baseNCodec the codec.
      * @param doEncode set to true to perform encoding, else decoding.
      */
-    protected BaseNCodecInputStream(final InputStream inputStream, final BaseNCodec baseNCodec, final boolean doEncode) {
+    protected BaseNCodecInputStream(final InputStream inputStream, final T baseNCodec, final boolean doEncode) {
         super(inputStream);
         this.doEncode = doEncode;
         this.baseNCodec = baseNCodec;