Initialize project with JsonFetcher implementation, Gradle setup, and IntelliJ configuration.

2026-04-23 05:20:41 +02:00
commit 00b3dbda8c
16 changed files with 579 additions and 0 deletions
@@ -0,0 +1,97 @@
+package de.catmangames.jsonfetcher;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.IOException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class JsonFetcher {
+
+    private final String baseUrl;
+    private final HttpClient client;
+    private final ObjectMapper mapper;
+    private final long cacheTtlMs;
+
+    private final Map<String, long[]> cacheTimestamps = new ConcurrentHashMap<>();
+    private final Map<String, String> cacheData = new ConcurrentHashMap<>();
+
+    private JsonFetcher(Builder b) {
+        this.baseUrl = b.baseUrl.endsWith("/") ? b.baseUrl : b.baseUrl + "/";
+        this.client = HttpClient.newBuilder()
+                .connectTimeout(Duration.ofSeconds(b.timeoutSec))
+                .build();
+        this.mapper = new ObjectMapper();
+        this.cacheTtlMs = b.cacheTtlMs;
+    }
+
+    public <T> T fetch(String path, Class<T> type) throws IOException {
+        return mapper.readValue(getRaw(path), type);
+    }
+
+    public <T> T fetch(String path, TypeReference<T> type) throws IOException {
+        return mapper.readValue(getRaw(path), type);
+    }
+
+    private String getRaw(String path) throws IOException {
+        if (cacheTtlMs > 0 && cacheData.containsKey(path)) {
+            long age = System.currentTimeMillis() - cacheTimestamps.get(path)[0];
+            if (age < cacheTtlMs) return cacheData.get(path);
+        }
+
+        HttpRequest req = HttpRequest.newBuilder()
+                .uri(java.net.URI.create(baseUrl + path))
+                .GET()
+                .build();
+
+        try {
+            HttpResponse<String> res = client.send(req, HttpResponse.BodyHandlers.ofString());
+            if (res.statusCode() != 200)
+                throw new IOException("HTTP " + res.statusCode() + " für: " + path);
+
+            String body = res.body();
+            if (cacheTtlMs > 0) {
+                cacheData.put(path, body);
+                cacheTimestamps.put(path, new long[]{System.currentTimeMillis()});
+            }
+            return body;
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new IOException("Request unterbrochen", e);
+        }
+    }
+
+    public static Builder builder(String baseUrl) {
+        return new Builder(baseUrl);
+    }
+
+    public static class Builder {
+        private final String baseUrl;
+        private long timeoutSec = 5;
+        private long cacheTtlMs = 0;
+
+        public Builder(String baseUrl) {
+            this.baseUrl = baseUrl;
+        }
+
+        public Builder timeout(long seconds) {
+            this.timeoutSec = seconds;
+            return this;
+        }
+
+        /** TTL in Millisekunden, 0 = Cache deaktiviert */
+        public Builder cache(long ttlMs) {
+            this.cacheTtlMs = ttlMs;
+            return this;
+        }
+
+        public JsonFetcher build() {
+            return new JsonFetcher(this);
+        }
+    }
+}