Add support to MessageDigestCalculatingInputStream for setting a

consumer for
ProxyInputStream.afterRead(int)

Author: garydgregory

src/changes/changes.xml

@@ -72,6 +72,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Add support to ChecksumInputStream for setting a consumer for ProxyInputStream.afterRead(int).</action>
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Add support to ThrottledInputStream for setting a consumer for ProxyInputStream.afterRead(int).</action>
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Add support to ObservableInputStream for setting a consumer for ProxyInputStream.afterRead(int).</action>
+      <action dev="ggregory" type="add"                due-to="Gary Gregory">Add support to MessageDigestCalculatingInputStream for setting a consumer for ProxyInputStream.afterRead(int).</action>
       <!-- UPDATE -->
       <action dev="ggregory" type="update"             due-to="Gary Gregory">Bump org.apache.commons:commons-parent from 74 to 78 #670, #676, #679, #688.</action>
       <action dev="ggregory" type="update"             due-to="Gary Gregory">Bump commons.bytebuddy.version from 1.15.1 to 1.15.10 #672, #673, #685, #686, #694, #696, #698.</action>

src/main/java/org/apache/commons/io/input/MessageDigestCalculatingInputStream.java

@@ -21,10 +21,9 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.security.Provider;
+import java.util.Arrays;
 import java.util.Objects;
 
-import org.apache.commons.io.build.AbstractStreamBuilder;
-
 /**
  * Calculates a checksum using a {@link MessageDigest}, for example, a SHA-512 sum.
  * <p>
@@ -57,12 +56,15 @@ public class MessageDigestCalculatingInputStream extends ObservableInputStream {
      *   .setMessageDigest("SHA-512")
      *   .get();}
      * </pre>
+     * <p>
+     * <em>The MD5 cryptographic algorithm is weak and should not be used.</em>
+     * </p>
      *
      * @see #get()
      * @since 2.12.0
      */
     // @formatter:on
-    public static class Builder extends AbstractStreamBuilder<MessageDigestCalculatingInputStream, Builder> {
+    public static class Builder extends AbstractBuilder<Builder> {
 
         private MessageDigest messageDigest;
 
@@ -101,16 +103,16 @@ public Builder() {
          * @throws IOException                   if an I/O error occurs.
          * @see #getInputStream()
          */
-        @SuppressWarnings("resource")
         @Override
         public MessageDigestCalculatingInputStream get() throws IOException {
-            return new MessageDigestCalculatingInputStream(getInputStream(), messageDigest);
+            setObservers(Arrays.asList(new MessageDigestMaintainingObserver(messageDigest)));
+            return new MessageDigestCalculatingInputStream(this);
         }
 
         /**
          * Sets the message digest.
          * <p>
-         * The MD5 cryptographic algorithm is weak and should not be used.
+         * <em>The MD5 cryptographic algorithm is weak and should not be used.</em>
          * </p>
          *
          * @param messageDigest the message digest.
@@ -122,7 +124,7 @@ public void setMessageDigest(final MessageDigest messageDigest) {
         /**
          * Sets the name of the name of the message digest algorithm.
          * <p>
-         * The MD5 cryptographic algorithm is weak and should not be used.
+         * <em>The MD5 cryptographic algorithm is weak and should not be used.</em>
          * </p>
          *
          * @param algorithm the name of the algorithm. See the MessageDigest section in the
@@ -197,6 +199,11 @@ static MessageDigest getDefaultMessageDigest() throws NoSuchAlgorithmException {
 
     private final MessageDigest messageDigest;
 
+    private MessageDigestCalculatingInputStream(final Builder builder) throws IOException {
+        super(builder);
+        this.messageDigest = builder.messageDigest;
+    }
+
     /**
      * Constructs a new instance, which calculates a signature on the given stream, using a {@link MessageDigest} with the "MD5" algorithm.
      * <p>

src/test/java/org/apache/commons/io/input/MessageDigestCalculatingInputStreamTest.java

@@ -20,6 +20,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertThrowsExactly;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
@@ -28,11 +29,14 @@
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.security.MessageDigest;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.commons.codec.digest.DigestUtils;
 import org.apache.commons.codec.digest.MessageDigestAlgorithms;
+import org.apache.commons.io.IOExceptionList;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.io.input.MessageDigestCalculatingInputStream.Builder;
+import org.apache.commons.io.test.CustomIOException;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -50,6 +54,32 @@ private MessageDigestCalculatingInputStream createInputStream(final InputStream
         return MessageDigestCalculatingInputStream.builder().setInputStream(origin).get();
     }
 
+    @Test
+    public void testAfterReadConsumer() throws Exception {
+        final AtomicBoolean boolRef = new AtomicBoolean();
+        // @formatter:off
+        try (InputStream bounded = MessageDigestCalculatingInputStream.builder()
+                .setCharSequence("Hi")
+                .setAfterRead(i -> boolRef.set(true))
+                .get()) {
+            IOUtils.consume(bounded);
+        }
+        // @formatter:on
+        assertTrue(boolRef.get());
+        // Throwing
+        final String message = "test exception message";
+        // @formatter:off
+        try (InputStream bounded = MessageDigestCalculatingInputStream.builder()
+                .setCharSequence("Hi")
+                .setAfterRead(i -> {
+                    throw new CustomIOException(message);
+                })
+                .get()) {
+            assertTrue(assertThrowsExactly(IOExceptionList.class, () -> IOUtils.consume(bounded)).getMessage().contains(message));
+        }
+        // @formatter:on
+    }
+
     @SuppressWarnings("resource")
     @Test
     public void testAvailableAfterClose() throws Exception {