THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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To achieve reverseRange and reverseAll, we can generate a new class like below, we can also reuse lots of code from RangeQuery, to simplify the code we choose reuse the RangeQuery Codecode.
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@Evolving
public final class ReverseRangeQuery<K, V> implements Query<KeyValueIterator<K, V>> {
private final Optional<K> lower;
private final Optional<K> upper;
private ReverseRangeQuery(final Optional<K> lower, final Optional<K> upper) {
this.lower = lower;
this.upper = upper;
}
/**
* Interactive range query using a lower and upper bound to filter the keys returned.
* @param lower The key that specifies the lower bound of the range
* @param upper The key that specifies the upper bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> ReverseRangeQuery<K, V> withRange(final K lower, final K upper) {
return new ReverseRangeQuery<>(Optional.ofNullable(lower), Optional.ofNullable(upper));
}
/**
* Interactive range query using an upper bound to filter the keys returned.
* If both <K,V> are null, RangQuery returns a full range scan.
* @param upper The key that specifies the upper bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> ReverseRangeQuery<K, V> withUpperBound(final K upper) {
return new ReverseRangeQuery<>(Optional.empty(), Optional.of(upper));
}
/**
* Interactive range query using a lower bound to filter the keys returned.
* @param lower The key that specifies the lower bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> ReverseRangeQuery<K, V> withLowerBound(final K lower) {
return new ReverseRangeQuery<>(Optional.of(lower), Optional.empty());
}
/**
* Interactive scan query that returns all records in the store.
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> ReverseRangeQuery<K, V> withNoBounds() {
return new ReverseRangeQuery<>(Optional.empty(), Optional.empty());
}
/**
* The lower bound of the query, if specified.
*/
public Optional<K> getLowerBound() {
return lower;
}
/**
* The upper bound of the query, if specified
*/
public Optional<K> getUpperBound() {
return upper;
}
}
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we We add a variable reverse in RangeQuery , the fault value is false, we want do reverseQuery reverseRange or reverseAll, we can set it to true.
so Then we generate two public methods:
The method, the first one is isReverse() , if this method return true, do reverseQuery otherwise do rangeQuery
the second method is setReverse() , if we want the query do reverseQuery, we can use this method to set the reverse to true, so this RangeQuery time, rangeQuery Stand for ReverseRangeQueryreverseQuery.
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/**
* Interactive query for issuing range queries and scans over KeyValue stores.
* <p>
* A range query retrieves a set of records, specified using an upper and/or lower bound on the keys.
* <p>
* A scan query retrieves all records contained in the store.
* <p>
* If the reverse is false, do RangeQuery. If the reverse is true do ReverseRangeQuery
*/
@Evolving
public final class RangeQuery<K, V> implements Query<KeyValueIterator<K, V>> {
private final Optional<K> lower;
private final Optional<K> upper;
private boolean reverse;
private RangeQuery(final Optional<K> lower, final Optional<K> upper) {
this.lower = lower;
this.upper = upper;
}
/**
* Interactive range query using a lower and upper bound to filter the keys returned.
* @param lower The key that specifies the lower bound of the range
* @param upper The key that specifies the upper bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> RangeQuery<K, V> withRange(final K lower, final K upper) {
return new RangeQuery<>(Optional.ofNullable(lower), Optional.ofNullable(upper));
}
/**
* Check whether the Query is ReverseRangeQuery.
*/
public boolean isReverse() {
return reverse;
}
/**
* Set the Query to ReverseRangeQuery.
*/
public void setReverse() {
this.reverse = true;
}
/**
* Interactive range query using an upper bound to filter the keys returned.
* If both <K,V> are null, RangQuery returns a full range scan.
* @param upper The key that specifies the upper bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> RangeQuery<K, V> withUpperBound(final K upper) {
return new RangeQuery<>(Optional.empty(), Optional.of(upper));
}
/**
* Interactive range query using a lower bound to filter the keys returned.
* @param lower The key that specifies the lower bound of the range
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> RangeQuery<K, V> withLowerBound(final K lower) {
return new RangeQuery<>(Optional.of(lower), Optional.empty());
}
/**
* Interactive scan query that returns all records in the store.
* @param <K> The key type
* @param <V> The value type
*/
public static <K, V> RangeQuery<K, V> withNoBounds() {
return new RangeQuery<>(Optional.empty(), Optional.empty());
}
/**
* The lower bound of the query, if specified.
*/
public Optional<K> getLowerBound() {
return lower;
}
/**
* The upper bound of the query, if specified
*/
public Optional<K> getUpperBound() {
return upper;
}
} |
Test Plan
Because this This time, we want aim to achieve implement reverseRange and reverseAll, if we want to better know whether the reverseRange and reverseAll result is correct or not, we have to do some change in IQv2StoreIntegrationTest. At before, we store the query result in a set, set cannot tell us the order of the result, so I use the list to store the query result, so we can know the different between the rangeQuery and reverseRangeQuery. To ensure the accuracy of the results for both, modifications to IQv2StoreIntegrationTest are necessary. Previously, we stored query results in a set, which doesn't retain order. I've since switched to using a list to store the query results. This allows us to discern the differences between rangeQuery and reverseQuery.
Compatibility, Deprecation, and Migration Plan
- Because we have already have
RangeQueryclass, so we can achieve the ReverseRangeQuery following RangeQueryupdate some code to achieve reverseRange and reverseAll. - Since nothing is deprecated in this KIP, users have no need to migrate unless they want to.
Rejected Alternatives
InitiallyAt first, we planned to implement ReverseRangeQuery from scratch. However, after discussions, we want decided to reuse some of the RangeQuery code in RangeQuery , but , allowing RangeQuery to possess the reverseQuery functionality. Therefore, in the end, we find reuse the code will lead some problem, so we rewrite some methods to achieve ReverseRangeQuery chose not to add a new ReverseRangeQuery class but instead to enhance the RangeQuery with new features.