refactor: move LazyRead into KeyValueAccess

* remove unused KeyValueAccessLazyReadData
* make KeyValueAccessReadData package-private

Author: bogovicj

src/main/java/org/janelia/saalfeldlab/n5/FileSystemKeyValueAccess.java

@@ -86,8 +86,6 @@
 import java.util.Iterator;
 import java.util.stream.Stream;
 
-import org.janelia.saalfeldlab.n5.readdata.KeyValueAccessReadData;
-import org.janelia.saalfeldlab.n5.readdata.LazyRead;
 import org.janelia.saalfeldlab.n5.readdata.ReadData;
 
 /**

src/main/java/org/janelia/saalfeldlab/n5/HttpKeyValueAccess.java

@@ -33,8 +33,6 @@
 import org.apache.commons.lang3.function.TriFunction;
 import org.janelia.saalfeldlab.n5.N5Exception.N5IOException;
 import org.janelia.saalfeldlab.n5.http.ListResponseParser;
-import org.janelia.saalfeldlab.n5.readdata.KeyValueAccessReadData;
-import org.janelia.saalfeldlab.n5.readdata.LazyRead;
 import org.janelia.saalfeldlab.n5.readdata.ReadData;
 
 import java.io.Closeable;

src/main/java/org/janelia/saalfeldlab/n5/KeyValueAccess.java

@@ -363,4 +363,47 @@ default URI uri(final String uriString) throws URISyntaxException {
 	 *            if an error occurs during deletion
 	 */
 	public void delete(final String normalPath) throws N5IOException;
+
+	/**
+	 * A lazy reading strategy for lazy, partial reading of data from some source.
+	 * <p>
+	 * Implementations of this interface handle the specifics of accessing data from
+	 * their respective sources.
+	 * 
+	 * @see ReadData
+	 * @see KeyValueAccessReadData
+	 */
+	interface LazyRead {
+
+		/**
+		 * Materializes a portion of the data into a concrete {@link ReadData}
+		 * instance.
+		 * <p>
+		 * This method performs the actual read operation from the underlying
+		 * source, loading only the requested portion of data. The implementation
+		 * should handle bounds checking and throw appropriate exceptions for
+		 * invalid ranges.
+		 *
+		 * @param offset
+		 *            the starting position in the data source
+		 * @param length
+		 *            the number of bytes to read, or -1 to read from offset to end
+		 * @return a materialized {@link ReadData} instance containing the requested
+		 *         data
+		 * @throws N5IOException
+		 *             if any I/O error occurs
+		 */
+		ReadData materialize(long offset, long length) throws N5IOException;
+
+		/**
+		 * Returns the total size of the data source in bytes.
+		 * 
+		 * @return the size of the data source in bytes
+		 * @throws N5IOException
+		 * 		if an I/O error occurs while trying to get the length
+		 */
+		long size() throws N5IOException;
+
+	}
+
 }

src/main/java/org/janelia/saalfeldlab/n5/KeyValueAccessLazyReadData.java

@@ -1,21 +1,27 @@
-package org.janelia.saalfeldlab.n5.readdata;
+package org.janelia.saalfeldlab.n5;
 
 import java.io.InputStream;
 
+import org.janelia.saalfeldlab.n5.KeyValueAccess.LazyRead;
 import org.janelia.saalfeldlab.n5.N5Exception.N5IOException;
+import org.janelia.saalfeldlab.n5.readdata.ReadData;
 
+/**
+ * A {@link ReadData} implementation that reads from a {@link KeyValueAccess}
+ * backend through a {@link LazyRead} object.
+ */
 public class KeyValueAccessReadData implements ReadData {
 
     private final LazyRead lazyRead;
     private ReadData materialized;
     private final long offset;
     private long length;
 
-    public KeyValueAccessReadData(LazyRead lazyRead) {
+    KeyValueAccessReadData(LazyRead lazyRead) {
         this(lazyRead, 0, -1);
     }
 
-    public KeyValueAccessReadData(final LazyRead lazyRead, final long offset, final long length) {
+    KeyValueAccessReadData(final LazyRead lazyRead, final long offset, final long length) {
         this.lazyRead = lazyRead;
         this.offset = offset;
         this.length = length;
@@ -28,6 +34,18 @@ public ReadData materialize() throws N5IOException {
         return materialized;
     }
 
+	/**
+	 * Returns a {@link ReadData} whose length is limited to the given value.
+	 * <p>
+	 * This implementation defers a material read operation if allowed
+	 * by the {@link LazyRead}.
+	 *
+	 * @param length
+	 *            the length of the resulting ReadData
+	 * @return a length-limited ReadData
+	 * @throws N5IOException
+	 *             if an I/O error occurs while trying to get the length
+	 */
     @Override
     public ReadData slice(final long offset, final long length) throws N5IOException {
         if (offset < 0)

…/n5/readdata/KeyValueAccessReadData.java …alfeldlab/n5/KeyValueAccessReadData.javasrc/main/java/org/janelia/saalfeldlab/n5/readdata/KeyValueAccessReadData.java renamed to src/main/java/org/janelia/saalfeldlab/n5/KeyValueAccessReadData.java src/main/java/org/janelia/saalfeldlab/n5/readdata/KeyValueAccessReadData.java renamed to src/main/java/org/janelia/saalfeldlab/n5/KeyValueAccessReadData.java

@@ -33,7 +33,6 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import org.apache.commons.io.output.ProxyOutputStream;
-import org.janelia.saalfeldlab.n5.N5Exception;
 import org.janelia.saalfeldlab.n5.N5Exception.N5IOException;
 
 class LazyReadData implements ReadData {