org.dizitart.no2.store.NitriteMap Maven / Gradle / Ivy
/*
* Copyright (c) 2017-2020. Nitrite 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
*
* http://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 org.dizitart.no2.store;
import org.dizitart.no2.common.meta.Attributes;
import org.dizitart.no2.common.meta.AttributesAware;
import org.dizitart.no2.common.RecordStream;
import org.dizitart.no2.common.tuples.Pair;
import static org.dizitart.no2.common.Constants.META_MAP_NAME;
import static org.dizitart.no2.common.util.StringUtils.isNullOrEmpty;
/**
* Represents a Nitrite key-value pair map. Every piece of
* data in a Nitrite database is stored in {@link NitriteMap}.
*
* @param the type of key
* @param the type of value
* @author Anindya Chatterjee.
* @since 1.0
*/
public interface NitriteMap extends AttributesAware, AutoCloseable {
/**
* Determines if the map contains a mapping for the
* specified key.
*
* @param key key whose presence in this map is to be tested
* @return `true` if this map contains a mapping for the specified key.
*/
boolean containsKey(Key key);
/**
* Gets the value mapped with the specified key or null otherwise.
*
* @param key the key
* @return the value, or null if the key not found.
*/
Value get(Key key);
/**
* Removes all entries in the map.
*/
void clear();
/**
* Indicates if the map already is closed.
*
* @return the boolean
*/
boolean isClosed();
/**
* Closes this {@link NitriteMap}.
* */
void close();
/**
* Gets a {@link RecordStream} view of the values contained in
* this map.
*
* @return the collection view of all values in this map.
*/
Iterable values();
/**
* Gets a {@link RecordStream} view of the keys contained in this map.
*
* @return a set view of the keys contained in this map.
*/
Iterable keys();
/**
* Removes the mapping for a key from this map if it is present.
*
* @param key the key whose mapping is to be removed from this map.
* @return the value that has been removed.
*/
Value remove(Key key);
/**
* Associates the specified value with the specified key in this map.
* If the map previously contained a mapping for
* the key, the old value is replaced by the specified value.
*
* @param key key with which the specified value is to be associated (may not be null).
* @param value value to be associated with the specified key (may not be null).
*/
void put(Key key, Value value);
/**
* Get the number of entries, as an integer. Integer.MAX_VALUE is returned if
* there are more than these entries.
*
* @return the number of entries, as an integer.
*/
long size();
/**
* Add a key-value pair if it does not yet exist.
*
* @param key the key (may not be null)
* @param value the new value
* @return the old value if the key existed, or `null` otherwise.
*/
Value putIfAbsent(Key key, Value value);
/**
* Get the first key in the map, or null if the map is empty.
*
* @return the result.
*/
Key firstKey();
/**
* Get the last key in the map, or null if the map is empty.
*
* @return the result.
*/
Key lastKey();
/**
* Get the lest key that is greater than the given key, or null if no
* such key exists.
*
* @param key the key
* @return the result.
*/
Key higherKey(Key key);
/**
* Get the least key that is greater than or equal to this key.
*
* @param key the key
* @return the result.
*/
Key ceilingKey(Key key);
/**
* Get the largest key that is smaller than the given key, or null if no
* such key exists.
*
* @param key the key
* @return the result.
*/
Key lowerKey(Key key);
/**
* Get the largest key that is smaller or equal to this key.
*
* @param key the key
* @return the result.
*/
Key floorKey(Key key);
/**
* Indicates whether the map is empty.
*
* @return `true` if the map is empty; `false` otherwise.
*/
boolean isEmpty();
/**
* Gets the parent {@link NitriteStore} where this map is stored.
*
* @return the store where this map is stored.
*/
NitriteStore getStore();
/**
* Gets name of this map.
*
* @return the name of this map.
*/
String getName();
/**
* Gets a {@link RecordStream} view of the mappings contained in this map.
*
* @return a set view of the mappings contained in this map.
*/
RecordStream> entries();
/**
* Gets a reversed {@link RecordStream} view of the mappings contained in this map.
*
* @return the record stream
*/
RecordStream> reversedEntries();
/**
* Deletes the map from the store.
*/
void drop();
/**
* Indicates if this map is dropped already.
*
* @return the boolean result
*/
boolean isDropped();
/**
* Gets the attributes of this map.
* */
default Attributes getAttributes() {
if (!isDropped()) {
NitriteMap metaMap = getStore().openMap(META_MAP_NAME, String.class, Attributes.class);
if (metaMap != null && !getName().contentEquals(META_MAP_NAME)) {
return metaMap.get(getName());
}
}
return null;
}
/**
* Sets the attributes for this map.
* */
default void setAttributes(Attributes attributes) {
if (!isDropped()) {
NitriteMap metaMap = getStore().openMap(META_MAP_NAME, String.class, Attributes.class);
if (metaMap != null && !getName().contentEquals(META_MAP_NAME)) {
metaMap.put(getName(), attributes);
}
}
}
/**
* Update last modified time of the map.
*/
default void updateLastModifiedTime() {
if (!isDropped()) {
if (isNullOrEmpty(getName())
|| META_MAP_NAME.equals(getName())) return;
NitriteMap metaMap = getStore().openMap(META_MAP_NAME, String.class, Attributes.class);
if (metaMap != null) {
Attributes attributes = metaMap.get(getName());
if (attributes == null) {
attributes = new Attributes(getName());
metaMap.put(getName(), attributes);
}
attributes.set(Attributes.LAST_MODIFIED_TIME, Long.toString(System.currentTimeMillis()));
}
}
}
}
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