Fix IntelliJ warnings

src/main/java/io/airlift/compress/snappy/Crc32C.java

@@ -21,7 +21,7 @@
  * and implemented on many Intel chipsets supporting SSE4.2.
  */
 // this code was taken from Apache Hadoop
-class Crc32C
+final class Crc32C
         implements Checksum
 {
     private static final int MASK_DELTA = 0xa282ead8;
@@ -126,6 +126,7 @@ public void update(byte[] b, int off, int len)
         crc = localCrc;
     }
 
+    @Override
     public void update(int b)
     {
         crc = (crc >>> 8) ^ T8_0[(crc ^ b) & 0xff];

src/main/java/io/airlift/compress/zstd/BitInputStream.java

@@ -25,7 +25,7 @@
  * <p>
  * ... [16 17 18 19 20 21 22 23] [8 9 10 11 12 13 14 15] [0 1 2 3 4 5 6 7]
  */
-class BitInputStream
+final class BitInputStream
 {
     private BitInputStream()
     {
@@ -36,7 +36,7 @@ public static boolean isEndOfStream(long startAddress, long currentAddress, int
         return startAddress == currentAddress && bitsConsumed == Long.SIZE;
     }
 
-    static long readTail(Object inputBase, long inputAddress, int inputSize)
+    private static long readTail(Object inputBase, long inputAddress, int inputSize)
     {
         long bits = UNSAFE.getByte(inputBase, inputAddress) & 0xFF;
 
@@ -59,7 +59,7 @@ static long readTail(Object inputBase, long inputAddress, int inputSize)
     }
 
     /**
-     * @return numberOfBits in the low order bits of a long
+     * @return numberOfBits in the low-order bits of a long
      */
     public static long peekBits(int bitsConsumed, long bitContainer, int numberOfBits)
     {
@@ -69,7 +69,7 @@ public static long peekBits(int bitsConsumed, long bitContainer, int numberOfBit
     /**
      * numberOfBits must be > 0
      *
-     * @return numberOfBits in the low order bits of a long
+     * @return numberOfBits in the low-order bits of a long
      */
     public static long peekBitsFast(int bitsConsumed, long bitContainer, int numberOfBits)
     {

src/main/java/io/airlift/compress/zstd/Constants.java

@@ -13,7 +13,7 @@
  */
 package io.airlift.compress.zstd;
 
-class Constants
+final class Constants
 {
     public static final int SIZE_OF_BYTE = 1;
     public static final int SIZE_OF_SHORT = 2;

src/main/java/io/airlift/compress/zstd/DoubleFastBlockCompressor.java

@@ -24,6 +24,7 @@ class DoubleFastBlockCompressor
     private static final int SEARCH_STRENGTH = 8;
     private static final int REP_MOVE = Constants.REPEATED_OFFSET_COUNT - 1;
 
+    @Override
     public int compressBlock(Object inputBase, final long inputAddress, int inputSize, SequenceStore output, BlockCompressionState state, RepeatedOffsets offsets, CompressionParameters parameters)
     {
         int matchSearchLength = Math.max(parameters.getSearchLength(), 4);

src/main/java/io/airlift/compress/zstd/FiniteStateEntropy.java

@@ -22,7 +22,7 @@
 import static io.airlift.compress.zstd.Util.verify;
 import static sun.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
 
-class FiniteStateEntropy
+final class FiniteStateEntropy
 {
     public static final int MAX_SYMBOL = 255;
     public static final int MAX_TABLE_LOG = 12;

src/main/java/io/airlift/compress/zstd/Histogram.java

@@ -18,7 +18,7 @@
 import static io.airlift.compress.zstd.UnsafeUtil.UNSAFE;
 import static sun.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
 
-class Histogram
+final class Histogram
 {
     private Histogram()
     {

src/main/java/io/airlift/compress/zstd/HuffmanCompressor.java

@@ -17,7 +17,7 @@
 import static io.airlift.compress.zstd.Constants.SIZE_OF_SHORT;
 import static io.airlift.compress.zstd.UnsafeUtil.UNSAFE;
 
-class HuffmanCompressor
+final class HuffmanCompressor
 {
     private HuffmanCompressor()
     {

src/main/java/io/airlift/compress/zstd/SequenceEncoder.java

@@ -31,7 +31,7 @@
 import static io.airlift.compress.zstd.UnsafeUtil.UNSAFE;
 import static io.airlift.compress.zstd.Util.checkArgument;
 
-class SequenceEncoder
+final class SequenceEncoder
 {
     private static final int DEFAULT_LITERAL_LENGTH_NORMALIZED_COUNTS_LOG = 6;
     private static final short[] DEFAULT_LITERAL_LENGTH_NORMALIZED_COUNTS = {4, 3, 2, 2, 2, 2, 2, 2,

src/main/java/io/airlift/compress/zstd/SequenceStore.java

@@ -17,7 +17,7 @@
 import static io.airlift.compress.zstd.UnsafeUtil.UNSAFE;
 import static sun.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
 
-class SequenceStore
+final class SequenceStore
 {
     public final byte[] literalsBuffer;
     public int literalsLength;

src/main/java/io/airlift/compress/zstd/ZstdFrameCompressor.java

@@ -32,7 +32,7 @@
 import static io.airlift.compress.zstd.Util.put24BitLittleEndian;
 import static sun.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
 
-class ZstdFrameCompressor
+final class ZstdFrameCompressor
 {
     static final int MAX_FRAME_HEADER_SIZE = 14;
 

src/test/java/io/airlift/compress/AbstractTestCompression.java

@@ -562,13 +562,13 @@ private void verifyCompressByteBuffer(Compressor compressor, ByteBuffer expected
         if (expected.remaining() > 1) {
             ByteBuffer duplicate = expected.duplicate();
             duplicate.get(); // skip one byte
-            compressor.compress(duplicate, ByteBuffer.allocate(((Buffer) compressed).remaining()));
+            compressor.compress(duplicate, ByteBuffer.allocate(compressed.remaining()));
         }
 
         compressor.compress(expected.duplicate(), compressed);
         ((Buffer) compressed).flip();
 
-        ByteBuffer uncompressed = ByteBuffer.allocate(((Buffer) expected).remaining());
+        ByteBuffer uncompressed = ByteBuffer.allocate(expected.remaining());
 
         // TODO: validate with "control" decompressor
         getDecompressor().decompress(compressed, uncompressed);

src/test/java/io/airlift/compress/deflate/MockJdkDeflateCompressor.java

@@ -22,6 +22,7 @@ public class MockJdkDeflateCompressor
 {
     private static final int OVERHEAD = 128;
 
+    @Override
     public int maxCompressedLength(int uncompressedSize)
     {
         return uncompressedSize + OVERHEAD;

src/test/java/io/airlift/compress/gzip/MockJdkGzipCompressor.java

@@ -22,6 +22,7 @@ public class MockJdkGzipCompressor
 {
     private static final int OVERHEAD = 128;
 
+    @Override
     public int maxCompressedLength(int uncompressedSize)
     {
         return uncompressedSize + OVERHEAD;

src/test/java/io/airlift/compress/snappy/TestSnappyStream.java

@@ -21,7 +21,6 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -116,7 +115,7 @@ void testEmptyCompression()
     @Test
     void testShortBlockHeader()
     {
-        assertThatThrownBy(() -> uncompressBlock(new byte[] {0}))
+        assertThatThrownBy(() -> uncompress(blockToStream(new byte[] {0})))
                 .isInstanceOf(EOFException.class)
                 .hasMessageContaining("block header");
     }
@@ -125,7 +124,7 @@ void testShortBlockHeader()
     void testShortBlockData()
     {
         // flag = 0, size = 8, crc32c = 0, block data= [x, x]
-        assertThatThrownBy(() -> uncompressBlock(new byte[] {1, 8, 0, 0, 0, 0, 0, 0, 'x', 'x'}))
+        assertThatThrownBy(() -> uncompress(blockToStream(new byte[] {1, 8, 0, 0, 0, 0, 0, 0, 'x', 'x'})))
                 .isInstanceOf(EOFException.class)
                 .hasMessageContaining("reading frame");
     }
@@ -135,7 +134,7 @@ void testUnskippableChunkFlags()
     {
         for (int i = 2; i <= 0x7f; i++) {
             int value = i;
-            assertThatThrownBy(() -> uncompressBlock(new byte[] {(byte) value, 5, 0, 0, 0, 0, 0, 0, 0}))
+            assertThatThrownBy(() -> uncompress(blockToStream(new byte[] {(byte) value, 5, 0, 0, 0, 0, 0, 0, 0})))
                     .isInstanceOf(IOException.class);
         }
     }
@@ -145,7 +144,7 @@ void testSkippableChunkFlags()
     {
         for (int i = 0x80; i <= 0xfe; i++) {
             try {
-                uncompressBlock(new byte[] {(byte) i, 5, 0, 0, 0, 0, 0, 0, 0});
+                uncompress(blockToStream(new byte[] {(byte) i, 5, 0, 0, 0, 0, 0, 0, 0}));
             }
             catch (IOException e) {
                 throw new AssertionError("exception thrown with flag: " + Integer.toHexString(i), e);
@@ -157,7 +156,7 @@ void testSkippableChunkFlags()
     void testInvalidBlockSizeZero()
     {
         // flag = '0', block size = 4, crc32c = 0
-        assertThatThrownBy(() -> uncompressBlock(new byte[] {1, 4, 0, 0, 0, 0, 0, 0}))
+        assertThatThrownBy(() -> uncompress(blockToStream(new byte[] {1, 4, 0, 0, 0, 0, 0, 0})))
                 .isInstanceOf(IOException.class)
                 .hasMessageMatching(".*invalid length.*4.*");
     }
@@ -166,7 +165,7 @@ void testInvalidBlockSizeZero()
     void testInvalidChecksum()
     {
         // flag = 0, size = 5, crc32c = 0, block data = [a]
-        assertThatThrownBy(() -> uncompressBlock(new byte[] {1, 5, 0, 0, 0, 0, 0, 0, 'a'}))
+        assertThatThrownBy(() -> uncompress(blockToStream(new byte[] {1, 5, 0, 0, 0, 0, 0, 0, 'a'})))
                 .isInstanceOf(IOException.class)
                 .hasMessage("Corrupt input: invalid checksum");
     }
@@ -272,12 +271,6 @@ void testLargerFrames_compressed_smaller_raw_larger()
         assertThat(random).isEqualTo(uncompressed);
     }
 
-    private static byte[] uncompressBlock(byte[] block)
-            throws IOException
-    {
-        return uncompress(blockToStream(block));
-    }
-
     private static byte[] blockToStream(byte[] block)
     {
         byte[] stream = new byte[SnappyFramed.HEADER_BYTES.length + block.length];
@@ -499,15 +492,4 @@ private static byte[] uncompress(byte[] compressed)
     {
         return toByteArray(new SnappyFramedInputStream(new ByteArrayInputStream(compressed)));
     }
-
-    private static File[] getTestFiles()
-    {
-        File[] testFiles = TEST_DATA_DIR.listFiles();
-        assertThat(testFiles != null && testFiles.length > 0)
-                .withFailMessage("No test files at " + TEST_DATA_DIR.getAbsolutePath())
-                .isTrue();
-        return testFiles;
-    }
-
-    private static final File TEST_DATA_DIR = new File("testdata");
 }

src/test/java/io/airlift/compress/zstd/TestZstd.java

@@ -67,8 +67,8 @@ void testDecompressWithOutputPaddingAndChecksum()
     {
         int padding = 1021;
 
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/with-checksum.zst"));
-        byte[] uncompressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/with-checksum"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/with-checksum.zst"));
+        byte[] uncompressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/with-checksum"));
 
         byte[] output = new byte[uncompressed.length + padding * 2]; // pre + post padding
         int decompressedSize = getDecompressor().decompress(compressed, 0, compressed.length, output, padding, output.length - padding);
@@ -80,8 +80,8 @@ void testDecompressWithOutputPaddingAndChecksum()
     void testConcatenatedFrames()
             throws IOException
     {
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames.zst"));
-        byte[] uncompressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames.zst"));
+        byte[] uncompressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames"));
 
         byte[] output = new byte[uncompressed.length];
         getDecompressor().decompress(compressed, 0, compressed.length, output, 0, output.length);
@@ -93,7 +93,7 @@ void testConcatenatedFrames()
     void testInvalidSequenceOffset()
             throws IOException
     {
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/offset-before-start.zst"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/offset-before-start.zst"));
         byte[] output = new byte[compressed.length * 10];
 
         assertThatThrownBy(() -> getDecompressor().decompress(compressed, 0, compressed.length, output, 0, output.length))
@@ -109,7 +109,7 @@ void testSmallLiteralsAfterIncompressibleLiterals()
         // which ended up emitting raw literals due to insufficient gain
         Compressor compressor = getCompressor();
 
-        byte[] original = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/small-literals-after-incompressible-literals"));
+        byte[] original = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/small-literals-after-incompressible-literals"));
         int maxCompressLength = compressor.maxCompressedLength(original.length);
 
         byte[] compressed = new byte[maxCompressLength];
@@ -129,7 +129,7 @@ void testLargeRle()
 
         Compressor compressor = getCompressor();
 
-        byte[] original = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/large-rle"));
+        byte[] original = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/large-rle"));
         int maxCompressLength = compressor.maxCompressedLength(original.length);
 
         byte[] compressed = new byte[maxCompressLength];
@@ -149,7 +149,7 @@ void testIncompressibleData()
 
         Compressor compressor = getCompressor();
 
-        byte[] original = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/incompressible"));
+        byte[] original = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/incompressible"));
         int maxCompressLength = compressor.maxCompressedLength(original.length);
 
         byte[] compressed = new byte[maxCompressLength];
@@ -200,9 +200,8 @@ private void testGetDecompressedSize(DataSet dataSet)
     void testVerifyMagicInAllFrames()
             throws IOException
     {
-        Compressor compressor = getCompressor();
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/bad-second-frame.zst"));
-        byte[] uncompressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/bad-second-frame.zst"));
+        byte[] uncompressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames"));
         byte[] output = new byte[uncompressed.length];
         assertThatThrownBy(() -> getDecompressor().decompress(compressed, 0, compressed.length, output, 0, output.length))
                 .isInstanceOf(MalformedInputException.class)

src/test/java/io/airlift/compress/zstd/TestZstdCodec.java

@@ -76,8 +76,8 @@ protected Decompressor getVerifyDecompressor()
     void testConcatenatedFrames()
             throws IOException
     {
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames.zst"));
-        byte[] uncompressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames.zst"));
+        byte[] uncompressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames"));
 
         byte[] output = new byte[uncompressed.length];
         getVerifyDecompressor().decompress(compressed, 0, compressed.length, output, 0, output.length);

src/test/java/io/airlift/compress/zstd/TestZstdCodecByteAtATime.java

@@ -77,8 +77,8 @@ protected Decompressor getVerifyDecompressor()
     void testConcatenatedFrames()
             throws IOException
     {
-        byte[] compressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames.zst"));
-        byte[] uncompressed = Resources.toByteArray(getClass().getClassLoader().getResource("data/zstd/multiple-frames"));
+        byte[] compressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames.zst"));
+        byte[] uncompressed = Resources.toByteArray(Resources.getResource(getClass(), "data/zstd/multiple-frames"));
 
         byte[] output = new byte[uncompressed.length];
         getVerifyDecompressor().decompress(compressed, 0, compressed.length, output, 0, output.length);