Add SubkeyLookupFactory class

pgp-cert-d-java-jdbc-sqlite-lookup/src/main/java/pgp/cert_d/jdbc/sqlite/DatabaseSubkeyLookupFactory.java

@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.cert_d.jdbc.sqlite;
+
+import pgp.cert_d.subkey_lookup.SubkeyLookup;
+import pgp.cert_d.subkey_lookup.SubkeyLookupFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.sql.SQLException;
+
+/**
+ * Implementation of {@link SubkeyLookupFactory} which creates a SQLite-based {@link DatabaseSubkeyLookup}.
+ */
+public class DatabaseSubkeyLookupFactory implements SubkeyLookupFactory {
+
+    @Override
+    public SubkeyLookup createFileBasedInstance(File baseDirectory) {
+        File databaseFile = new File(baseDirectory, "_pgpainless_subkey_map.db");
+        SubkeyLookupDao dao;
+        try {
+            if (!databaseFile.exists()) {
+                databaseFile.createNewFile();
+            }
+            dao = SqliteSubkeyLookupDaoImpl.forDatabaseFile(databaseFile);
+        } catch (SQLException | IOException e) {
+            throw new RuntimeException(e);
+        }
+        return new DatabaseSubkeyLookup(dao);
+    }
+}

pgp-cert-d-java/src/main/java/pgp/cert_d/subkey_lookup/InMemorySubkeyLookupFactory.java

@@ -0,0 +1,14 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.cert_d.subkey_lookup;
+
+import java.io.File;
+
+public class InMemorySubkeyLookupFactory implements SubkeyLookupFactory {
+    @Override
+    public SubkeyLookup createFileBasedInstance(File baseDirectory) {
+        return new InMemorySubkeyLookup();
+    }
+}

pgp-cert-d-java/src/main/java/pgp/cert_d/subkey_lookup/SubkeyLookupFactory.java

@@ -0,0 +1,18 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.cert_d.subkey_lookup;
+
+import java.io.File;
+
+public interface SubkeyLookupFactory {
+
+    /**
+     * Create a new {@link SubkeyLookup} instance that lives in the given baseDirectory.
+     *
+     * @param baseDirectory base directory
+     * @return subkey lookup
+     */
+    SubkeyLookup createFileBasedInstance(File baseDirectory);
+}