Add support for STRALGO LCS #1280

Original pull request: #1282.

Author: dengliming

src/main/java/io/lettuce/core/AbstractRedisAsyncCommands.java

@@ -1427,6 +1427,11 @@ public RedisFuture<Long> strlen(K key) {
         return dispatch(commandBuilder.strlen(key));
     }
 
+    @Override
+    public RedisFuture<StringMatchResult> stralgoLcs(StrAlgoArgs args) {
+        return dispatch(commandBuilder.stralgoLcs(args));
+    }
+
     @Override
     public RedisFuture<Set<V>> sunion(K... keys) {
         return dispatch(commandBuilder.sunion(keys));

src/main/java/io/lettuce/core/AbstractRedisReactiveCommands.java

@@ -1503,6 +1503,11 @@ public Mono<Long> strlen(K key) {
         return createMono(() -> commandBuilder.strlen(key));
     }
 
+    @Override
+    public Mono<StringMatchResult> stralgoLcs(StrAlgoArgs strAlgoArgs) {
+        return createMono(() -> commandBuilder.stralgoLcs(strAlgoArgs));
+    }
+
     @Override
     public Flux<V> sunion(K... keys) {
         return createDissolvingFlux(() -> commandBuilder.sunion(keys));

src/main/java/io/lettuce/core/RedisCommandBuilder.java

@@ -1972,6 +1972,14 @@ Command<K, V, Long> strlen(K key) {
         return createCommand(STRLEN, new IntegerOutput<>(codec), key);
     }
 
+    Command<K, V, StringMatchResult> stralgoLcs(StrAlgoArgs strAlgoArgs) {
+        LettuceAssert.notNull(strAlgoArgs, "StrAlgoArgs " + MUST_NOT_BE_NULL);
+
+        CommandArgs<K, V> args = new CommandArgs<>(codec);
+        strAlgoArgs.build(args);
+        return createCommand(STRALGO, new StringMatchResultOutput<>(codec, strAlgoArgs.isWithIdx()), args);
+    }
+
     Command<K, V, Set<V>> sunion(K... keys) {
         notEmpty(keys);
 

src/main/java/io/lettuce/core/StrAlgoArgs.java

@@ -0,0 +1,168 @@
+/*
+ * Copyright 2011-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.lettuce.core;
+
+import io.lettuce.core.internal.LettuceAssert;
+import io.lettuce.core.protocol.CommandArgs;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Argument list builder for the Redis <a href="http://redis.io/commands/stralgo">STRALGO</a> command.
+ * Static import the methods from {@link StrAlgoArgs.Builder} and call the methods: {@code block(…)} .
+ * <p>
+ * {@link StrAlgoArgs} is a mutable object and instances should be used only once to avoid shared mutable state.
+ *
+ * @author dengliming
+ * @since 6.0
+ */
+public class StrAlgoArgs implements CompositeArgument {
+
+    private boolean justLen;
+    private int minMatchLen;
+    private boolean withMatchLen;
+    private boolean withIdx;
+    private By by = By.STRINGS;
+    private String[] keys;
+    private Charset charset = StandardCharsets.UTF_8;
+
+    /**
+     * Builder entry points for {@link StrAlgoArgs}.
+     */
+    public static class Builder {
+
+        /**
+         * Utility constructor.
+         */
+        private Builder() {
+        }
+
+        /**
+         * Creates new {@link StrAlgoArgs} by keys.
+         *
+         * @return new {@link StrAlgoArgs} with {@literal By KEYS} set.
+         */
+        public static StrAlgoArgs keys(String... keys) {
+            return new StrAlgoArgs().by(By.KEYS, keys);
+        }
+
+        /**
+         * Creates new {@link StrAlgoArgs} by strings.
+         *
+         * @return new {@link StrAlgoArgs} with {@literal By STRINGS} set.
+         */
+        public static StrAlgoArgs strings(String... strings) {
+            return new StrAlgoArgs().by(By.STRINGS, strings);
+        }
+
+        /**
+         * Creates new {@link StrAlgoArgs} by strings and charset.
+         *
+         * @return new {@link StrAlgoArgs} with {@literal By STRINGS} set.
+         */
+        public static StrAlgoArgs strings(Charset charset, String... strings) {
+            return new StrAlgoArgs().by(By.STRINGS, strings).charset(charset);
+        }
+    }
+    /**
+     * restrict the list of matches to the ones of a given minimal length.
+     *
+     * @return {@code this} {@link StrAlgoArgs}.
+     */
+    public StrAlgoArgs minMatchLen(int minMatchLen) {
+        this.minMatchLen = minMatchLen;
+        return this;
+    }
+
+    /**
+     * Request just the length of the match for results.
+     *
+     * @return {@code this} {@link StrAlgoArgs}.
+     */
+    public StrAlgoArgs justLen() {
+        justLen = true;
+        return this;
+    }
+
+    /**
+     * Request match len for results.
+     *
+     * @return {@code this} {@link StrAlgoArgs}.
+     */
+    public StrAlgoArgs withMatchLen() {
+        withMatchLen = true;
+        return this;
+    }
+
+    /**
+     * Request match position in each strings for results.
+     *
+     * @return {@code this} {@link StrAlgoArgs}.
+     */
+    public StrAlgoArgs withIdx() {
+        withIdx = true;
+        return this;
+    }
+
+    public StrAlgoArgs by(By by, String... keys) {
+        this.by = by;
+        this.keys = keys;
+        return this;
+    }
+
+    public boolean isWithIdx() {
+        return withIdx;
+    }
+
+    public StrAlgoArgs charset(Charset charset) {
+        this.charset = charset;
+        return this;
+    }
+
+    public enum By {
+        STRINGS, KEYS
+    }
+
+    public <K, V> void build(CommandArgs<K, V> args) {
+        LettuceAssert.notEmpty(keys, "strings or keys must be not empty");
+
+        args.add("LCS");
+        args.add(by.name());
+        for (String key : keys) {
+            if (by == By.STRINGS) {
+                args.add(key.getBytes(charset));
+            } else {
+                args.add(key);
+            }
+        }
+        if (justLen) {
+            args.add("LEN");
+        }
+        if (withIdx) {
+            args.add("IDX");
+        }
+
+        if (minMatchLen > 0) {
+            args.add("MINMATCHLEN");
+            args.add(minMatchLen);
+        }
+
+        if (withMatchLen) {
+            args.add("WITHMATCHLEN");
+        }
+    }
+}

src/main/java/io/lettuce/core/StringMatchResult.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2011-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.lettuce.core;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Result for STRALGO command
+ *
+ * @author dengliming
+ */
+public class StringMatchResult {
+
+    private String matchString;
+    private List<MatchedPosition> matches = new ArrayList<>();
+    private long len;
+
+    public StringMatchResult matchString(String matchString) {
+        this.matchString = matchString;
+        return this;
+    }
+
+    public StringMatchResult addMatch(MatchedPosition match) {
+        this.matches.add(match);
+        return this;
+    }
+
+    public StringMatchResult len(long len) {
+        this.len = len;
+        return this;
+    }
+
+    public String getMatchString() {
+        return matchString;
+    }
+
+    public List<MatchedPosition> getMatches() {
+        return matches;
+    }
+
+    public long getLen() {
+        return len;
+    }
+
+    /**
+     * match position in each strings
+     */
+    public static class MatchedPosition {
+        private Position a;
+        private Position b;
+        private long matchLen;
+
+        public MatchedPosition(Position a, Position b, long matchLen) {
+            this.a = a;
+            this.b = b;
+            this.matchLen = matchLen;
+        }
+
+        public Position getA() {
+            return a;
+        }
+
+        public void setA(Position a) {
+            this.a = a;
+        }
+
+        public Position getB() {
+            return b;
+        }
+
+        public void setB(Position b) {
+            this.b = b;
+        }
+
+        public long getMatchLen() {
+            return matchLen;
+        }
+
+        public void setMatchLen(long matchLen) {
+            this.matchLen = matchLen;
+        }
+    }
+
+    /**
+     * position range
+     */
+    public static class Position {
+        private final long start;
+        private final long end;
+
+        public Position(long start, long end) {
+            this.start = start;
+            this.end = end;
+        }
+
+        public long getStart() {
+            return start;
+        }
+
+        public long getEnd() {
+            return end;
+        }
+    }
+}

src/main/java/io/lettuce/core/api/async/RedisStringAsyncCommands.java

@@ -23,6 +23,8 @@
 import io.lettuce.core.RedisFuture;
 import io.lettuce.core.SetArgs;
 import io.lettuce.core.output.KeyValueStreamingChannel;
+import io.lettuce.core.StrAlgoArgs;
+import io.lettuce.core.StringMatchResult;
 
 /**
  * Asynchronous executed commands for Strings.
@@ -374,4 +376,13 @@ public interface RedisStringAsyncCommands<K, V> {
      * @return Long integer-reply the length of the string at {@code key}, or {@code 0} when {@code key} does not exist.
      */
     RedisFuture<Long> strlen(K key);
+
+    /**
+     * The STRALGO implements complex algorithms that operate on strings.
+     *
+     * Right now the only algorithm implemented is the LCS algorithm (longest common substring).
+     * @param strAlgoArgs
+     * @return StringMatchResult
+     */
+    RedisFuture<StringMatchResult> stralgoLcs(StrAlgoArgs strAlgoArgs);
 }

src/main/java/io/lettuce/core/api/reactive/RedisStringReactiveCommands.java

@@ -24,6 +24,8 @@
 import io.lettuce.core.SetArgs;
 import io.lettuce.core.Value;
 import io.lettuce.core.output.KeyValueStreamingChannel;
+import io.lettuce.core.StrAlgoArgs;
+import io.lettuce.core.StringMatchResult;
 
 /**
  * Reactive executed commands for Strings.
@@ -375,4 +377,13 @@ public interface RedisStringReactiveCommands<K, V> {
      * @return Long integer-reply the length of the string at {@code key}, or {@code 0} when {@code key} does not exist.
      */
     Mono<Long> strlen(K key);
+
+    /**
+     * The STRALGO implements complex algorithms that operate on strings.
+     *
+     * Right now the only algorithm implemented is the LCS algorithm (longest common substring).
+     * @param strAlgoArgs
+     * @return StringMatchResult
+     */
+    Mono<StringMatchResult> stralgoLcs(StrAlgoArgs strAlgoArgs);
 }

src/main/java/io/lettuce/core/api/sync/RedisStringCommands.java

@@ -22,6 +22,8 @@
 import io.lettuce.core.KeyValue;
 import io.lettuce.core.SetArgs;
 import io.lettuce.core.output.KeyValueStreamingChannel;
+import io.lettuce.core.StrAlgoArgs;
+import io.lettuce.core.StringMatchResult;
 
 /**
  * Synchronous executed commands for Strings.
@@ -373,4 +375,13 @@ public interface RedisStringCommands<K, V> {
      * @return Long integer-reply the length of the string at {@code key}, or {@code 0} when {@code key} does not exist.
      */
     Long strlen(K key);
+
+    /**
+     * The STRALGO implements complex algorithms that operate on strings.
+     *
+     * Right now the only algorithm implemented is the LCS algorithm (longest common substring).
+     * @param strAlgoArgs
+     * @return StringMatchResult
+     */
+    StringMatchResult stralgoLcs(StrAlgoArgs strAlgoArgs);
 }