T10: PwzRegistrySource with PwzLookupClient [checkpoint]

szpitale-graph/src/main/java/com/developx/szpitale/ingest/source/PwzLookupClient.java

@@ -0,0 +1,8 @@
+package com.developx.szpitale.ingest.source;
+
+import java.util.List;
+
+@FunctionalInterface
+public interface PwzLookupClient {
+    List<String> query(String fullName);
+}

szpitale-graph/src/main/java/com/developx/szpitale/ingest/source/PwzRegistrySource.java

@@ -0,0 +1,31 @@
+package com.developx.szpitale.ingest.source;
+
+import java.util.List;
+import java.util.Optional;
+
+public class PwzRegistrySource {
+
+    private final PwzLookupClient client;
+
+    public PwzRegistrySource(PwzLookupClient client) {
+        this.client = client;
+    }
+
+    public Optional<String> lookupPwz(String fullName) {
+        if (client == null || fullName == null || fullName.isBlank()) {
+            return Optional.empty();
+        }
+
+        List<String> results = client.query(fullName);
+
+        if (results == null || results.isEmpty()) {
+            return Optional.empty();
+        }
+
+        if (results.size() == 1) {
+            return Optional.of(results.get(0));
+        }
+
+        return Optional.empty();
+    }
+}