Adds com.fathzer.jchess.uci.helper.DeferredReadMoveLibrary

src/main/java/com/fathzer/jchess/uci/helper/DeferredReadMoveLibrary.java

@@ -0,0 +1,99 @@
+package com.fathzer.jchess.uci.helper;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Optional;
+
+import com.fathzer.games.MoveGenerator;
+import com.fathzer.games.ai.evaluation.EvaluatedMove;
+import com.fathzer.games.movelibrary.MoveLibrary;
+
+/** A move library that encapsulates another move library and read its content outside of its constructor.
+ * <br>This typically allows an UCI engine to instantiate a move library during the launch process, and
+ * deferred the effective read of the moves during the <i>isReady</i> command execution as specified in
+ * UCI protocol. 
+ * @param <M> The type of a move
+ * @param <B> The type of the move generator used by the UCI engine
+ */
+public class DeferredReadMoveLibrary<M, B extends MoveGenerator<M>> implements MoveLibrary<M, B> {
+	/** A interface that can read an object from an URL and sends an IOException if sommething goes wrong. 
+	 * @param <T> The type of the read object
+	 */
+	@FunctionalInterface
+	public static interface IOReader<T> {
+		/** Reads an object.
+		 * @param url The url where to read the object
+		 * @return The object
+		 * @throws IOException If something went wrong
+		 */
+		T read(URL url) throws IOException;
+	}
+
+	private final String url;
+	private final IOReader<MoveLibrary<M, B>> reader;
+	private MoveLibrary<M, B> internal;
+
+	/** Constructor.
+	 * @param url The url where to read the MoveLibrary
+	 * @param reader The reader to read the library.
+	 */
+	public DeferredReadMoveLibrary(String url, IOReader<MoveLibrary<M,B>> reader) {
+		if (url==null || reader==null) {
+			throw new IllegalArgumentException();
+		}
+		this.url = url;
+		this.reader = reader;
+	}
+
+	/** {@inheritDoc}
+	 * <br>If the move library is not initialized, an empty optional is returned.
+	 */
+	@Override
+	public Optional<EvaluatedMove<M>> apply(B board) {
+		if (internal==null) {
+			return Optional.empty();
+		}
+		return internal.apply(board);
+	}
+
+	/** Tests if this move library should be initialized.
+	 * @return false if initialization has been made and succeeded.
+	 * @see #init()
+	 */
+	public boolean isInitRequired() {
+		return internal==null;
+	}
+
+	/** Initializes this move library.
+	 * @throws IOException
+	 */
+	public void init() throws IOException {
+		if (isInitRequired()) {
+			internal = reader.read(toURL(this.url));
+		}
+	}
+
+	static URL toURL(String path) throws IOException {
+		URL url;
+		try {
+			url = new URL(path);
+		} catch (MalformedURLException e) {
+			File file = new File(path);
+			if (!file.exists()) {
+				throw new FileNotFoundException();
+			}
+			url = file.toURI().toURL();
+		}
+		return url;
+	}
+
+	/** Gets the URL where the data should be/has been read.
+	 * @return A String
+	 */
+	public String getUrl() {
+		return url;
+	}
+}

src/test/java/com/fathzer/jchess/uci/helper/DeferredReadBookTest.java

@@ -0,0 +1,50 @@
+package com.fathzer.jchess.uci.helper;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URL;
+import java.util.Optional;
+
+import org.junit.jupiter.api.Test;
+
+import com.fathzer.games.MoveGenerator;
+import com.fathzer.games.ai.evaluation.EvaluatedMove;
+import com.fathzer.games.ai.evaluation.Evaluation;
+import com.fathzer.games.movelibrary.MoveLibrary;
+
+class DeferredReadMoveLibraryTest {
+
+	@SuppressWarnings("unchecked")
+	private final MoveGenerator<String> mv = mock(MoveGenerator.class);
+
+	@Test
+	void test() throws Exception {
+		String httpsURL = "https://myApp.org/file.gz";
+		assertEquals(URI.create(httpsURL).toURL(), DeferredReadMoveLibrary.toURL(httpsURL));
+
+		assertThrows(IOException.class, () -> DeferredReadMoveLibrary.toURL("httpx://myApp.org/file.gz"));
+		assertThrows(IOException.class, () -> DeferredReadMoveLibrary.toURL("src/test/resources/unknownFile.json"));
+
+		final String path = "src/test/resources/FakeOpenings.txt";
+		final DeferredReadMoveLibrary<String, MoveGenerator<String>> rb = new DeferredReadMoveLibrary<>(path, this::readOpenings);
+		assertTrue(rb.isInitRequired());
+		assertTrue(rb.apply(mv).isEmpty());
+		rb.init();
+		assertFalse(rb.isInitRequired());
+		assertFalse(rb.apply(mv).isEmpty());
+		// A second init call should no throw any exception
+		rb.init();
+	}
+
+	private MoveLibrary<String, MoveGenerator<String>> readOpenings(URL url) {
+		return new MoveLibrary<String, MoveGenerator<String>>() {
+			@Override
+			public Optional<EvaluatedMove<String>> apply(MoveGenerator<String> board) {
+				return mv.equals(board) ? Optional.of(new EvaluatedMove<>("ok", Evaluation.score(100))) : Optional.empty(); 
+			}
+		};
+	}
+}

src/test/resources/FakeOpenings.txt

@@ -0,0 +1 @@
+File required by src/test/com.fathzer.jchess.uci.helper.DeferredReadBookTest.java