BAEL-3613: Reading All Available Redis Keys (#8490)

2020-01-23 22:00:12 +05:30
parent f46ea65783
commit 6bca22524a
10 changed files with 537 additions and 1 deletions
@@ -0,0 +1,149 @@
+package com.baeldung.redis_scan.client;
+
+import com.baeldung.redis_scan.iterator.RedisIterator;
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPool;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.*;
+
+public class RedisClient {
+    private static Logger log = LoggerFactory.getLogger(RedisClient.class);
+
+    private static volatile RedisClient instance = null;
+
+    private static JedisPool jedisPool;
+
+    public static RedisClient getInstance(String ip, final int port) {
+        if (instance == null) {
+            synchronized (RedisClient.class) {
+                if (instance == null) {
+                    instance = new RedisClient(ip, port);
+                }
+            }
+        }
+        return instance;
+    }
+
+    private RedisClient(String ip, int port) {
+        try {
+            if (jedisPool == null) {
+                jedisPool = new JedisPool(new URI("http://" + ip + ":" + port));
+            }
+        } catch (URISyntaxException e) {
+            log.error("Malformed server address", e);
+        }
+    }
+
+    public Long lpush(final String key, final String[] strings) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.lpush(key, strings);
+        } catch (Exception ex) {
+            log.error("Exception caught in lpush", ex);
+        }
+        return null;
+    }
+
+    public List<String> lrange(final String key, final long start, final long stop) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.lrange(key, start, stop);
+        } catch (Exception ex) {
+            log.error("Exception caught in lrange", ex);
+        }
+        return new LinkedList<String>();
+    }
+
+    public String hmset(final String key, final Map<String, String> hash) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.hmset(key, hash);
+        } catch (Exception ex) {
+            log.error("Exception caught in hmset", ex);
+        }
+        return null;
+    }
+
+    public Map<String, String> hgetAll(final String key) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.hgetAll(key);
+        } catch (Exception ex) {
+            log.error("Exception caught in hgetAll", ex);
+        }
+        return new HashMap<String, String>();
+    }
+
+    public Long sadd(final String key, final String... members) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.sadd(key, members);
+        } catch (Exception ex) {
+            log.error("Exception caught in sadd", ex);
+        }
+        return null;
+    }
+
+    public Set<String> smembers(final String key) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.smembers(key);
+        } catch (Exception ex) {
+            log.error("Exception caught in smembers", ex);
+        }
+        return new HashSet<String>();
+    }
+
+    public Long zadd(final String key, final Map<String, Double> scoreMembers) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.zadd(key, scoreMembers);
+        } catch (Exception ex) {
+            log.error("Exception caught in zadd", ex);
+        }
+        return 0L;
+    }
+
+    public Set<String> zrange(final String key, final long start, final long stop) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.zrange(key, start, stop);
+        } catch (Exception ex) {
+            log.error("Exception caught in zrange", ex);
+        }
+        return new HashSet<String>();
+    }
+
+    public String mset(final HashMap<String, String> keysValues) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            ArrayList<String> keysValuesArrayList = new ArrayList<String>();
+            keysValues.forEach((key, value) -> {
+                keysValuesArrayList.add(key);
+                keysValuesArrayList.add(value);
+            });
+            return jedis.mset((keysValuesArrayList.toArray(new String[keysValues.size()])));
+        } catch (Exception ex) {
+            log.error("Exception caught in mset", ex);
+        }
+        return null;
+    }
+
+    public Set<String> keys(final String pattern) {
+        try (Jedis jedis = jedisPool.getResource()) {
+            return jedis.keys(pattern);
+        } catch (Exception ex) {
+            log.error("Exception caught in keys", ex);
+        }
+        return new HashSet<String>();
+    }
+
+    public RedisIterator iterator(int initialScanCount, String pattern, ScanStrategy strategy) {
+        return new RedisIterator(jedisPool, initialScanCount, pattern, strategy);
+    }
+
+    public void flushAll() {
+        try (Jedis jedis = jedisPool.getResource()) {
+            jedis.flushAll();
+        } catch (Exception ex) {
+            log.error("Exception caught in flushAll", ex);
+        }
+    }
+
+}
@@ -0,0 +1,60 @@
+package com.baeldung.redis_scan.iterator;
+
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPool;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+public class RedisIterator<T> implements Iterator<List<T>> {
+
+    private static Logger log = LoggerFactory.getLogger(RedisIterator.class);
+    private static final int DEFAULT_SCAN_COUNT = 10;
+
+    private final JedisPool jedisPool;
+    private ScanParams scanParams;
+    private String cursor;
+    private ScanStrategy<T> strategy;
+
+    public RedisIterator(JedisPool jedisPool, int initialScanCount, String pattern, ScanStrategy<T> strategy) {
+        super();
+        this.jedisPool = jedisPool;
+        this.scanParams = new ScanParams().match(pattern).count(initialScanCount);
+        this.strategy = strategy;
+    }
+
+    public RedisIterator(JedisPool jedisPool, String pattern, ScanStrategy<T> strategy) {
+        super();
+        this.jedisPool = jedisPool;
+        this.scanParams = new ScanParams().match(pattern).count(DEFAULT_SCAN_COUNT);
+        this.strategy = strategy;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return !"0".equals(cursor);
+    }
+
+    @Override
+    public List<T> next() {
+        if (cursor == null) {
+            cursor = "0";
+        }
+        try (Jedis jedis = jedisPool.getResource()) {
+            ScanResult<T> scanResult = strategy.scan(jedis, cursor, scanParams);
+            cursor = scanResult.getCursor();
+            return scanResult.getResult();
+
+        } catch (Exception ex) {
+            log.error("Exception caught in next()", ex);
+        }
+        return new LinkedList<T>();
+    }
+
+}
@@ -0,0 +1,9 @@
+package com.baeldung.redis_scan.strategy;
+
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+
+public interface ScanStrategy<T> {
+    ScanResult<T> scan(Jedis jedis, String cursor, ScanParams scanParams);
+}
@@ -0,0 +1,25 @@
+package com.baeldung.redis_scan.strategy.impl;
+
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+
+import java.util.Map;
+import java.util.Map.Entry;
+
+public class Hscan implements ScanStrategy<Map.Entry<String, String>> {
+
+    private String key;
+
+    public Hscan(String key) {
+        super();
+        this.key = key;
+    }
+
+    @Override
+    public ScanResult<Entry<String, String>> scan(Jedis jedis, String cursor, ScanParams scanParams) {
+        return jedis.hscan(key, cursor, scanParams);
+    }
+
+}
@@ -0,0 +1,14 @@
+package com.baeldung.redis_scan.strategy.impl;
+
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+
+public class Scan implements ScanStrategy<String> {
+
+
+    public ScanResult<String> scan(Jedis jedis, String cursor, ScanParams scanParams) {
+        return jedis.scan(cursor, scanParams);
+    }
+}
@@ -0,0 +1,29 @@
+package com.baeldung.redis_scan.strategy.impl;
+
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+
+public class Sscan implements ScanStrategy<String> {
+
+    private String key;
+
+
+    public Sscan(String key) {
+        super();
+        this.key = key;
+    }
+
+    public String getKey() {
+        return key;
+    }
+
+    public void setKey(String key) {
+        this.key = key;
+    }
+
+    public ScanResult<String> scan(Jedis jedis, String cursor, ScanParams scanParams) {
+        return jedis.sscan(key, cursor, scanParams);
+    }
+}
@@ -0,0 +1,25 @@
+package com.baeldung.redis_scan.strategy.impl;
+
+import com.baeldung.redis_scan.strategy.ScanStrategy;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.ScanParams;
+import redis.clients.jedis.ScanResult;
+import redis.clients.jedis.Tuple;
+
+public class Zscan implements ScanStrategy<Tuple> {
+
+    private String key;
+
+
+    public Zscan(String key) {
+        super();
+        this.key = key;
+    }
+
+
+    @Override
+    public ScanResult<Tuple> scan(Jedis jedis, String cursor, ScanParams scanParams) {
+        return jedis.zscan(key, cursor, scanParams);
+    }
+
+}