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/*
* Copyright © 2016-2025 The LmdbJava Open Source Project
*
* 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.lmdbjava;
import static java.util.Objects.requireNonNull;
import static org.lmdbjava.KeyRangeType.BACKWARD_ALL;
import static org.lmdbjava.KeyRangeType.FORWARD_ALL;
/**
* Limits the range and direction of keys to iterate.
*
* <p>Immutable once created (although the buffers themselves may not be).
*
* @param <T> buffer type
*/
public final class KeyRange<T> {
private static final KeyRange<?> BK = new KeyRange<>(BACKWARD_ALL, null, null);
private static final KeyRange<?> FW = new KeyRange<>(FORWARD_ALL, null, null);
private final T start;
private final T stop;
private final KeyRangeType type;
/**
* Construct a key range.
*
* <p>End user code may find it more expressive to use one of the static methods provided on this
* class.
*
* @param type key type
* @param start start key (required if applicable for the passed range type)
* @param stop stop key (required if applicable for the passed range type)
*/
public KeyRange(final KeyRangeType type, final T start, final T stop) {
requireNonNull(type, "Key range type is required");
if (type.isStartKeyRequired()) {
requireNonNull(start, "Start key is required for this key range type");
}
if (type.isStopKeyRequired()) {
requireNonNull(stop, "Stop key is required for this key range type");
}
this.start = start;
this.stop = stop;
this.type = type;
}
/**
* Create a {@link KeyRangeType#FORWARD_ALL} range.
*
* @param <T> buffer type
* @return a key range (never null)
*/
public static <T> KeyRange<T> all() {
return (KeyRange<T>) FW;
}
/**
* Create a {@link KeyRangeType#BACKWARD_ALL} range.
*
* @param <T> buffer type
* @return a key range (never null)
*/
public static <T> KeyRange<T> allBackward() {
return (KeyRange<T>) BK;
}
/**
* Create a {@link KeyRangeType#FORWARD_AT_LEAST} range.
*
* @param <T> buffer type
* @param start start key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> atLeast(final T start) {
return new KeyRange<>(KeyRangeType.FORWARD_AT_LEAST, start, null);
}
/**
* Create a {@link KeyRangeType#BACKWARD_AT_LEAST} range.
*
* @param <T> buffer type
* @param start start key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> atLeastBackward(final T start) {
return new KeyRange<>(KeyRangeType.BACKWARD_AT_LEAST, start, null);
}
/**
* Create a {@link KeyRangeType#FORWARD_AT_MOST} range.
*
* @param <T> buffer type
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> atMost(final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_AT_MOST, null, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_AT_MOST} range.
*
* @param <T> buffer type
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> atMostBackward(final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_AT_MOST, null, stop);
}
/**
* Create a {@link KeyRangeType#FORWARD_CLOSED} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> closed(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_CLOSED, start, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_CLOSED} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> closedBackward(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_CLOSED, start, stop);
}
/**
* Create a {@link KeyRangeType#FORWARD_CLOSED_OPEN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> closedOpen(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_CLOSED_OPEN, start, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_CLOSED_OPEN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> closedOpenBackward(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_CLOSED_OPEN, start, stop);
}
/**
* Create a {@link KeyRangeType#FORWARD_GREATER_THAN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> greaterThan(final T start) {
return new KeyRange<>(KeyRangeType.FORWARD_GREATER_THAN, start, null);
}
/**
* Create a {@link KeyRangeType#BACKWARD_GREATER_THAN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> greaterThanBackward(final T start) {
return new KeyRange<>(KeyRangeType.BACKWARD_GREATER_THAN, start, null);
}
/**
* Create a {@link KeyRangeType#FORWARD_LESS_THAN} range.
*
* @param <T> buffer type
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> lessThan(final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_LESS_THAN, null, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_LESS_THAN} range.
*
* @param <T> buffer type
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> lessThanBackward(final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_LESS_THAN, null, stop);
}
/**
* Create a {@link KeyRangeType#FORWARD_OPEN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> open(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_OPEN, start, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_OPEN} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> openBackward(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_OPEN, start, stop);
}
/**
* Create a {@link KeyRangeType#FORWARD_OPEN_CLOSED} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> openClosed(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.FORWARD_OPEN_CLOSED, start, stop);
}
/**
* Create a {@link KeyRangeType#BACKWARD_OPEN_CLOSED} range.
*
* @param <T> buffer type
* @param start start key (required)
* @param stop stop key (required)
* @return a key range (never null)
*/
public static <T> KeyRange<T> openClosedBackward(final T start, final T stop) {
return new KeyRange<>(KeyRangeType.BACKWARD_OPEN_CLOSED, start, stop);
}
/**
* Start key.
*
* @return start key (may be null)
*/
public T getStart() {
return start;
}
/**
* Stop key.
*
* @return stop key (may be null)
*/
public T getStop() {
return stop;
}
/**
* Key range type.
*
* @return type (never null)
*/
public KeyRangeType getType() {
return type;
}
}