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本文次要钻研一下claudb的keys command
KeysCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/KeysCommand.java
@ReadOnly@Command("keys")@ParamLength(1)public class KeysCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { GlobPattern pattern = createPattern(request.getParam(0)); ImmutableSet<SafeString> keys = db.entrySet() .filter(matchPattern(pattern)) .filter(filterExpired(Instant.now()).negate()) .map(Tuple2::get1) .map(DatabaseKey::getValue); return convert(keys); } private GlobPattern createPattern(SafeString param) { return new GlobPattern(param.toString()); } private Matcher1<Tuple2<DatabaseKey, DatabaseValue>> filterExpired(Instant now) { return entry -> entry.get2().isExpired(now); } private Matcher1<Tuple2<DatabaseKey, DatabaseValue>> matchPattern(GlobPattern pattern) { return entry -> pattern.match(entry.get1().toString()); }}- KeysCommand实现了DBCommand接口，其execute办法先通过createPattern创立GlobPattern，之后遍历db.entrySet()，过滤出matchPattern的，再过滤出非expired的，最初返回
DeleteCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/DeleteCommand.java
@Command("del")@ParamLength(1)public class DeleteCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { int removed = 0; for (SafeString key : request.getParams()) { DatabaseValue value = db.remove(safeKey(key)); if (value != null) { removed += 1; } } return integer(removed); }}- DeleteCommand实现了DBCommand接口，其execute办法遍历request.getParams()执行db.remove(safeKey(key))，最初返回integer(removed)
ExistsCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/ExistsCommand.java
@ReadOnly@Command("exists")@ParamLength(1)public class ExistsCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { DatabaseValue value = db.get(safeKey(request.getParam(0))); return integer(value != null ? !value.isExpired(Instant.now()) : false); }}- ExistsCommand实现了DBCommand接口，其execute办法先通过db.get(safeKey(request.getParam(0)))获取DatabaseValue，之后判断是否null，非null的话再判断是否expired，非expired的返回true
TypeCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/TypeCommand.java
@ReadOnly@Command("type")@ParamLength(1)public class TypeCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { DatabaseValue value = db.get(safeKey(request.getParam(0))); if (value != null) { return status(value.getType().text()); } else { return status(DataType.NONE.text()); } }}- TypeCommand实现了DBCommand接口，其execute办法先通过db.get(safeKey(request.getParam(0)))获取DatabaseValue，若不为null则返回status(value.getType().text())，否则返回status(DataType.NONE.text())
RenameCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/RenameCommand.java
@Command("rename")@ParamLength(2)public class RenameCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { if (db.rename(safeKey(request.getParam(0)), safeKey(request.getParam(1)))) { return responseOk(); } else { return error("ERR no such key"); } }}- RenameCommand实现了DBCommand接口，其execute办法执行db.rename
ExpireCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/ExpireCommand.java
@Command("expire")@ParamLength(2)public class ExpireCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { try { DatabaseValue value = db.get(safeKey(request.getParam(0))); if (value != null) { db.put(safeKey(request.getParam(0)), value.expiredAt(parsetTtl(request.getParam(1)))); } return integer(value != null); } catch (NumberFormatException e) { return error("ERR value is not an integer or out of range"); } } private int parsetTtl(SafeString param) { return Integer.parseInt(param.toString()); }}- ExpireCommand实现了DBCommand接口，其execute办法先通过db.get(safeKey(request.getParam(0)))获取DatabaseValue，若不为null则执行value.expiredAt(parsetTtl(request.getParam(1)))，而后put进去
PersistCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/PersistCommand.java
@Command("persist")@ParamLength(1)public class PersistCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { DatabaseValue value = db.get(safeKey(request.getParam(0))); if (value != null) { db.put(safeKey(request.getParam(0)), value.noExpire()); } return integer(value != null); }}- PersistCommand办法实现了DBCommand接口，其execute办法先通过db.get(safeKey(request.getParam(0)))获取DatabaseValue，若不为null则执行db.put(safeKey(request.getParam(0)), value.noExpire())
TimeToLiveCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/TimeToLiveCommand.java
public abstract class TimeToLiveCommand implements DBCommand { @Override public RedisToken execute(Database db, Request request) { DatabaseValue value = db.get(safeKey(request.getParam(0))); if (value != null) { return keyExists(value); } else { return notExists(); } } protected abstract int timeToLive(DatabaseValue value, Instant now); private RedisToken keyExists(DatabaseValue value) { if (value.getExpiredAt() != null) { return hasExpiredAt(value); } else { return integer(-1); } } private RedisToken hasExpiredAt(DatabaseValue value) { Instant now = Instant.now(); if (!value.isExpired(now)) { return integer(timeToLive(value, now)); } else { return notExists(); } } private RedisToken notExists() { return integer(-2); }}- TimeToLiveCommand申明实现DBCommand接口，其execute接口先通过db.get(safeKey(request.getParam(0)))获取DatabaseValue，若为null则返回notExists，若不为null则执行keyExists；keyExists办法在value.getExpiredAt()不为null时执行hasExpiredAt办法；hasExpiredAt办法在value.isExpired(now)为false时返回integer(timeToLive(value, now))；timeToLive办法为形象办法，须要子类实现
TimeToLiveMillisCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/TimeToLiveMillisCommand.java
@Command("pttl")@ParamLength(1)public class TimeToLiveMillisCommand extends TimeToLiveCommand { @Override protected int timeToLive(DatabaseValue value, Instant now) { return (int) value.timeToLiveMillis(now); }}- TimeToLiveMillisCommand实现了TimeToLiveCommand接口，其timeToLive办法返回value.timeToLiveMillis(now)
TimeToLiveSecondsCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/key/TimeToLiveSecondsCommand.java
@Command("ttl")@ParamLength(1)public class TimeToLiveSecondsCommand extends TimeToLiveCommand { @Override protected int timeToLive(DatabaseValue value, Instant now) { return value.timeToLiveSeconds(now); }}- TimeToLiveSecondsCommand实现了TimeToLiveCommand接口，其timeToLive办法返回value.timeToLiveSeconds(now)
小结
claudb keys相干的command有KeysCommand、DeleteCommand、ExistsCommand、TypeCommand、RenameCommand、ExpireCommand、PersistCommand、TimeToLiveMillisCommand、TimeToLiveSecondsCommand
doc
- KeysCommand