[IO-427] Redice TrailerInputStream#copyTrailer to only one method

Author: ax-lothas

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

@@ -15,7 +15,6 @@
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import org.apache.commons.io.IOUtils;
 
 /**
@@ -166,15 +165,4 @@ public byte[] copyTrailer() {
         return this.trailer.clone();
     }
 
-    public void copyTrailer(final byte[] target, final int off, final int len) {
-        System.arraycopy(this.trailer, 0, target, off, Math.min(len, this.trailer.length));
-    }
-
-    public void copyTrailer(final byte[] target) {
-        this.copyTrailer(target, 0, target.length);
-    }
-
-    public void copyTrailer(final OutputStream target) throws IOException {
-        target.write(this.trailer);
-    }
 }

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

@@ -16,8 +16,6 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
-import java.io.StringWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -28,8 +26,6 @@
 import java.util.stream.Stream;
 
 import org.apache.commons.io.IOUtils;
-import org.apache.commons.io.function.IOConsumer;
-import org.apache.commons.io.output.WriterOutputStream;
 import org.apache.commons.lang3.StringUtils;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -128,15 +124,11 @@ public static InputStream createTestInputStream(
                         .iterator());
     }
 
-    public static String utf8String(
-            final IOConsumer<? super OutputStream> consumer) throws IOException {
-        try (StringWriter sw = new StringWriter();
-                WriterOutputStream wos = WriterOutputStream.builder().setCharset(StandardCharsets.UTF_8).setWriter(sw).get()) {
-            consumer.accept(wos);
-            wos.flush();
-            sw.flush();
-            return sw.toString();
-        }
+    public static String trailerUtf8String(
+            final TrailerInputStream tis)  {
+        final byte[] trailer = tis.copyTrailer();
+        Assertions.assertEquals(trailer.length, tis.getTrailerLength());
+        return new String(trailer, 0, trailer.length, StandardCharsets.UTF_8);
     }
 
     public static void assertDataTrailer(
@@ -157,9 +149,9 @@ public static void assertDataTrailer(
         Assertions.assertAll(
                 () -> Assertions.assertEquals(d, data + trailer, "Generation of expectation"),
                 () -> Assertions.assertEquals(trailerLength, trailer.length(), "Trailer length"),
-                () -> Assertions.assertEquals(data, utf8String(os::writeTo), "Data content"),
+                () -> Assertions.assertEquals(data, os.toString(StandardCharsets.UTF_8.name()), "Data content"),
                 () -> Assertions.assertEquals(
-                                trailer, utf8String(tis::copyTrailer), "Trailer content"));
+                                trailer, trailerUtf8String(tis), "Trailer content"));
     }
 
     @ParameterizedTest
@@ -174,7 +166,7 @@ public void testReadBytewise(final int trailerLength) throws IOException {
                 TrailerInputStream tis = new TrailerInputStream(is, trailerLength);
                 ByteArrayOutputStream os = new ByteArrayOutputStream()) {
             Assertions.assertEquals(
-                    StringUtils.repeat('a', trailerLength), utf8String(tis::copyTrailer));
+                    StringUtils.repeat('a', trailerLength), trailerUtf8String(tis));
             int read;
             while ((read = tis.read()) != IOUtils.EOF) {
                 os.write(read);
@@ -195,7 +187,7 @@ public void testReadWholeBlocks(final int trailerLength) throws IOException {
                 TrailerInputStream tis = new TrailerInputStream(is, trailerLength);
                 ByteArrayOutputStream os = new ByteArrayOutputStream()) {
             Assertions.assertEquals(
-                    StringUtils.repeat('a', trailerLength), utf8String(tis::copyTrailer));
+                    StringUtils.repeat('a', trailerLength), trailerUtf8String(tis));
             final byte[] buffer = new byte[chunkLength];
             int read;
             while ((read = tis.read(buffer)) != IOUtils.EOF) {
@@ -217,7 +209,7 @@ public void testReadLastBlockAlmostFull(final int trailerLength) throws IOExcept
                 TrailerInputStream tis = new TrailerInputStream(is, trailerLength);
                 ByteArrayOutputStream os = new ByteArrayOutputStream()) {
             Assertions.assertEquals(
-                    StringUtils.repeat('a', trailerLength), utf8String(tis::copyTrailer));
+                    StringUtils.repeat('a', trailerLength), trailerUtf8String(tis));
             final byte[] buffer = new byte[chunkLength + 3 * chunks];
             int offset = chunks;
             while (true) {
@@ -245,7 +237,7 @@ public void testReadLastBlockAlmostEmpty(final int trailerLength) throws IOExcep
                 TrailerInputStream tis = new TrailerInputStream(is, trailerLength);
                 ByteArrayOutputStream os = new ByteArrayOutputStream()) {
             Assertions.assertEquals(
-                    StringUtils.repeat('a', trailerLength), utf8String(tis::copyTrailer));
+                    StringUtils.repeat('a', trailerLength), trailerUtf8String(tis));
             final byte[] buffer = new byte[chunkLength + 3 * chunks];
             int offset = chunks;
             while (true) {