stage-6: add javadoc

src/main/java/ru/vk/itmo/viktorkorotkikh/io/read/AbstractSSTableReader.java

@@ -8,6 +8,13 @@
 import java.lang.foreign.MemorySegment;
 import java.lang.foreign.ValueLayout;
 
+/**
+ * Base class for implementing the sstable reader.
+ *
+ * @author vitekkor
+ * @see BaseSSTableReader
+ * @see CompressedSSTableReader
+ */
 public abstract class AbstractSSTableReader {
     protected final MemorySegment mappedSSTable;
     protected final MemorySegment mappedIndexFile;
@@ -26,6 +33,12 @@ protected AbstractSSTableReader(
         this.index = index;
     }
 
+    /**
+     * Returns entry by key.
+     * @param key entry`s key
+     * @return entry
+     * @throws IOException if an I/O error occurs.
+     */
     public Entry<MemorySegment> get(MemorySegment key) throws IOException {
         try {
             long entryOffset = getEntryOffset(key, SearchOption.EQ);
@@ -38,12 +51,38 @@ public Entry<MemorySegment> get(MemorySegment key) throws IOException {
         }
     }
 
+    /**
+     * Returns ordered iterator of entries with keys between from (inclusive) and to (exclusive).
+     * @param from lower bound of range (inclusive)
+     * @param to upper bound of range (exclusive)
+     * @return entries [from;to)
+     * @throws IOException if an I/O error occurs.
+     */
     public abstract LSMPointerIterator iterator(MemorySegment from, MemorySegment to) throws IOException;
 
+    /**
+     * Returns entry by index.
+     * @param index entry`s index from index file.
+     * @return entry
+     * @throws IOException if an I/O error occurs.
+     */
     protected abstract Entry<MemorySegment> getByIndex(long index) throws IOException;
 
+    /**
+     * Returns entry's index by key.
+     * @param key entry`s key
+     * @param searchOption Entity search parameter. {@link SearchOption#EQ} find equal by key,
+     *                     {@link SearchOption#GTE} find greater than or equal to,
+     *                     {@link SearchOption#LT} strictly less than
+     * @return offset (index)
+     * @throws IOException if an I/O error occurs.
+     */
     protected abstract long getEntryOffset(MemorySegment key, SearchOption searchOption) throws IOException;
 
+    /**
+     * SSTable has no tombstones.
+     * @return false if sstable has tombstones.
+     */
     public boolean hasNoTombstones() {
         return mappedIndexFile.get(ValueLayout.JAVA_BOOLEAN, 0);
     }

src/main/java/ru/vk/itmo/viktorkorotkikh/io/read/BaseSSTableReader.java

@@ -10,6 +10,11 @@
 import java.lang.foreign.ValueLayout;
 import java.util.NoSuchElementException;
 
+/**
+ * SSTable reader without compression.
+ *
+ * @author vitekkor
+ */
 public class BaseSSTableReader extends AbstractSSTableReader {
     private static final long METADATA_SIZE = Long.BYTES + 1L;
 

src/main/java/ru/vk/itmo/viktorkorotkikh/io/read/CompressedSSTableReader.java

@@ -5,6 +5,7 @@
 import ru.vk.itmo.viktorkorotkikh.LSMPointerIterator;
 import ru.vk.itmo.viktorkorotkikh.MemorySegmentComparator;
 import ru.vk.itmo.viktorkorotkikh.Utils;
+import ru.vk.itmo.viktorkorotkikh.compressor.Compressor;
 import ru.vk.itmo.viktorkorotkikh.decompressor.Decompressor;
 import ru.vk.itmo.viktorkorotkikh.decompressor.LZ4Decompressor;
 import ru.vk.itmo.viktorkorotkikh.decompressor.ZstdDecompressor;
@@ -19,6 +20,10 @@
 import java.util.NoSuchElementException;
 
 /**
+ * SSTable reader implementation with compression.
+ * Implementations of the {@link Decompressor} interface are used for decompression.
+ * <br/>
+ * <br/>
  * <B>compression info</B>:
  * isCompressed|algorithm|blocksCount|uncompressedBlockSize|block1Offset|block2Offset|blockNOffset
  * <p/>