69 lines
2.1 KiB
Java
69 lines
2.1 KiB
Java
package it.cavallium.dbengine.database.collections;
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import it.cavallium.dbengine.client.CompositeSnapshot;
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import it.cavallium.dbengine.database.LLDictionary;
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import it.cavallium.dbengine.database.LLDictionaryResultType;
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import it.cavallium.dbengine.database.LLRange;
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import it.cavallium.dbengine.database.LLSnapshot;
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import it.cavallium.dbengine.database.serialization.Serializer;
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import org.jetbrains.annotations.Nullable;
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import reactor.core.publisher.Mono;
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public class DatabaseSingle<U> implements DatabaseStageEntry<U> {
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private final LLDictionary dictionary;
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private final byte[] key;
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private final Serializer<U, byte[]> serializer;
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public DatabaseSingle(LLDictionary dictionary, byte[] key, Serializer<U, byte[]> serializer) {
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this.dictionary = dictionary;
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this.key = key;
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this.serializer = serializer;
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}
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private LLSnapshot resolveSnapshot(@Nullable CompositeSnapshot snapshot) {
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if (snapshot == null) {
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return null;
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} else {
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return snapshot.getSnapshot(dictionary);
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}
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}
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@Override
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public Mono<U> get(@Nullable CompositeSnapshot snapshot) {
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return dictionary.get(resolveSnapshot(snapshot), key).map(this::deserialize);
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}
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@Override
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public Mono<U> setAndGetPrevious(U value) {
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return dictionary.put(key, serialize(value), LLDictionaryResultType.PREVIOUS_VALUE).map(this::deserialize);
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}
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@Override
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public Mono<U> clearAndGetPrevious() {
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return dictionary.remove(key, LLDictionaryResultType.PREVIOUS_VALUE).map(this::deserialize);
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}
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@Override
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public Mono<Long> size(@Nullable CompositeSnapshot snapshot, boolean fast) {
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return dictionary
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.isRangeEmpty(resolveSnapshot(snapshot), LLRange.single(key))
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.map(empty -> empty ? 0L : 1L);
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}
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@Override
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public Mono<Boolean> isEmpty(@Nullable CompositeSnapshot snapshot) {
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return dictionary
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.isRangeEmpty(resolveSnapshot(snapshot), LLRange.single(key));
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}
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//todo: temporary wrapper. convert the whole class to buffers
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private U deserialize(byte[] bytes) {
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return serializer.deserialize(bytes);
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}
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//todo: temporary wrapper. convert the whole class to buffers
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private byte[] serialize(U bytes) {
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return serializer.serialize(bytes);
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}
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} |