Maven-like version range support

clickhouse-client/pom.xml

@@ -28,6 +28,11 @@
             </exclusions>
         </dependency>
 
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>dnsjava</groupId>
             <artifactId>dnsjava</artifactId>

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseCache.java

@@ -0,0 +1,57 @@
+package com.clickhouse.client;
+
+import java.util.function.Function;
+
+import com.clickhouse.client.cache.CaffeineCache;
+import com.clickhouse.client.cache.JdkLruCache;
+
+/**
+ * Wrapper interface depicts essential methods required by a client-side cache.
+ */
+public interface ClickHouseCache<K, V> {
+    /**
+     * Default cache size.
+     */
+    static final int DEFAULT_CACHE_SIZE = 50;
+
+    /**
+     * Creates a cache with specific capacity and load function.
+     *
+     * @param <K>           type of key
+     * @param <V>           type of value
+     * @param capacity      capacity of the cache, zero or negative number will be
+     *                      treated as {@link #DEFAULT_CACHE_SIZE}
+     * @param expireSeconds seconds to expire after access
+     * @param loadFunc      non-null load function
+     * @return cache
+     */
+    static <K, V> ClickHouseCache<K, V> create(int capacity, long expireSeconds, Function<K, V> loadFunc) {
+        ClickHouseCache<K, V> cache;
+
+        try {
+            cache = CaffeineCache.create(capacity, expireSeconds, loadFunc);
+        } catch (Throwable e) {
+            // ignore
+            cache = JdkLruCache.create(capacity, loadFunc);
+        }
+        return cache;
+    }
+
+    /**
+     * Gets value from cache if it exists.
+     *
+     * @param key key, in genernal should NOT be null
+     * @return non-null value in general
+     */
+    V get(K key);
+
+    /**
+     * Gets inner cache object to gain more access.
+     *
+     * @param <T>   type of the cache
+     * @param clazz non-null class of the cache
+     * @return inner cache object
+     * @throws NullPointerException
+     */
+    <T> T unwrap(Class<T> clazz);
+}

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseDataProcessor.java

@@ -8,7 +8,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Function;
 
 /**
  * This defines a data processor for dealing with one or multiple

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseDnsResolver.java

@@ -1,18 +1,15 @@
 package com.clickhouse.client;
 
 import java.net.InetSocketAddress;
+
 import com.clickhouse.client.config.ClickHouseDefaults;
 import com.clickhouse.client.logging.Logger;
 import com.clickhouse.client.logging.LoggerFactory;
-import org.xbill.DNS.Lookup;
-import org.xbill.DNS.Record;
-import org.xbill.DNS.SRVRecord;
-import org.xbill.DNS.TextParseException;
-import org.xbill.DNS.Type;
+import com.clickhouse.client.naming.SrvResolver;
 
 /**
  * Default DNS resolver. It tries to look up service record (SRV record) when
- * {@link com.clickhouse.client.config.ClickHouseDefaults#DNS_RESOLVE} is set to
+ * {@link com.clickhouse.client.config.ClickHouseDefaults#SRV_RESOLVE} is set to
  * {@code true}.
  */
 public class ClickHouseDnsResolver {
@@ -21,57 +18,25 @@ public class ClickHouseDnsResolver {
     private static final ClickHouseDnsResolver instance = ClickHouseUtils.getService(ClickHouseDnsResolver.class,
             new ClickHouseDnsResolver());
 
-    public static ClickHouseDnsResolver getInstance() {
-        return instance;
-    }
-
-    protected ClickHouseDnsResolver() {
-    }
+    protected static ClickHouseDnsResolver newInstance() {
+        ClickHouseDnsResolver resolver = null;
 
-    public InetSocketAddress resolve(ClickHouseProtocol protocol, String host, int port) {
-        if (protocol == null || host == null) {
-            throw new IllegalArgumentException("Non-null protocol and host are required");
-        }
-
-        if ((boolean) ClickHouseDefaults.DNS_RESOLVE.getEffectiveDefaultValue()) {
-            SRVRecord r = resolve(host, false);
-            if (r != null) {
-                host = r.getName().canonicalize().toString(true);
-                port = r.getPort();
+        if ((boolean) ClickHouseDefaults.SRV_RESOLVE.getEffectiveDefaultValue()) {
+            try {
+                resolver = new SrvResolver();
+            } catch (Throwable e) {
+                log.warn("Failed to enable SRV resolver due to:", e);
             }
-        } else {
-            host = ClickHouseDefaults.HOST.getEffectiveValue(host);
-            port = port <= 0 ? protocol.getDefaultPort() : port;
         }
 
-        return new InetSocketAddress(host, port);
+        return resolver == null ? new ClickHouseDnsResolver() : resolver;
     }
 
-    // TODO register a callback for DNS change?
-
-    protected SRVRecord resolve(String srvDns, boolean basedOnWeight) {
-        Record[] records = null;
-        try {
-            records = new Lookup(srvDns, Type.SRV).run();
-        } catch (TextParseException e) {
-            // fallback to a cached entry?
-            log.warn("Not able to resolve given DNS query: [%s]", srvDns, e);
-        }
-
-        SRVRecord record = null;
-        if (records != null) {
-            if (basedOnWeight) {
-                for (int i = 0; i < records.length; i++) {
-                    SRVRecord rec = (SRVRecord) records[i];
-                    if (record == null || record.getWeight() > rec.getWeight()) {
-                        record = rec;
-                    }
-                }
-            } else {
-                record = (SRVRecord) records[0];
-            }
-        }
+    public static ClickHouseDnsResolver getInstance() {
+        return instance;
+    }
 
-        return record;
+    public InetSocketAddress resolve(ClickHouseProtocol protocol, String host, int port) {
+        return new InetSocketAddress(host, port);
     }
 }

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseNode.java

@@ -2,7 +2,6 @@
 
 import java.io.Serializable;
 import java.net.InetSocketAddress;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;