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Cassandra support for Spring Data
/*
* Copyright 2017-2021 the original 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
*
* https://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.springframework.data.cassandra.core.query;
import java.nio.ByteBuffer;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Cassandra-specific {@link PageRequest} implementation providing access to {@link ByteBuffer paging state}. This class
* allows creation of the first page request and represents through Cassandra paging is based on the progress of fetched
* pages and allows forward-only navigation. Accessing a particular page requires fetching of all pages until the
* desired page is reached.
*
* The fetching progress is represented as {@link ByteBuffer paging state}. Query results are associated with a
* {@link com.datastax.oss.driver.api.core.cql.ExecutionInfo#getPagingState paging state} that is used on the next query
* as input parameter to continue page fetching.
*
* @author Mark Paluch
* @since 2.0
*/
public class CassandraPageRequest extends PageRequest {
private final @Nullable ByteBuffer pagingState;
private final boolean nextAllowed;
private CassandraPageRequest(int page, int size, Sort sort, @Nullable ByteBuffer pagingState, boolean nextAllowed) {
super(page, size, sort);
this.pagingState = pagingState;
this.nextAllowed = nextAllowed;
}
/**
* Creates a new unsorted {@link PageRequest}.
*
* @param page zero-based page index.
* @param size the size of the page to be returned.
* @throws IllegalArgumentException for page requests other than the first page.
*/
public static CassandraPageRequest of(int page, int size) {
Assert.isTrue(page == 0,
"Cannot create a Cassandra page request for an indexed page other than the first page (0).");
return of(page, size, Sort.unsorted());
}
/**
* Creates a new {@link PageRequest} with sort parameters applied.
*
* @param page zero-based page index.
* @param size the size of the page to be returned.
* @param sort must not be {@literal null}.
* @throws IllegalArgumentException for page requests other than the first page.
*/
public static CassandraPageRequest of(int page, int size, Sort sort) {
Assert.isTrue(page == 0,
"Cannot create a Cassandra page request for an indexed page other than the first page (0).");
return new CassandraPageRequest(page, size, sort, null, false);
}
/**
* Creates a new {@link PageRequest} with sort direction and properties applied.
*
* @param page zero-based page index.
* @param size the size of the page to be returned.
* @param direction must not be {@literal null}.
* @param properties must not be {@literal null}.
* @throws IllegalArgumentException for page requests other than the first page.
*/
public static CassandraPageRequest of(int page, int size, Direction direction, String... properties) {
Assert.isTrue(page == 0,
"Cannot create a Cassandra page request for an indexed page other than the first page (0).");
return of(page, size, Sort.by(direction, properties));
}
/**
* Creates a a {@link PageRequest} with sort direction and properties applied.
*
* @param current the current {@link Pageable}, must not be {@literal null}.
* @param pagingState the paging state associated with the current {@link Pageable}. Can be {@literal null} if there
* is no paging state associated.
*/
public static CassandraPageRequest of(Pageable current, @Nullable ByteBuffer pagingState) {
return new CassandraPageRequest(current.getPageNumber(), current.getPageSize(), current.getSort(), pagingState,
pagingState != null);
}
/**
* Creates a new unsorted {@link PageRequest} for the first page.
*
* @param size the size of the page to be returned.
*/
public static CassandraPageRequest first(int size) {
return of(0, size, Sort.unsorted());
}
/**
* Creates a new {@link PageRequest} with sort parameters applied for the first page.
*
* @param size the size of the page to be returned.
* @param sort must not be {@literal null}.
*/
public static CassandraPageRequest first(int size, Sort sort) {
return new CassandraPageRequest(0, size, sort, null, false);
}
/**
* Creates a new {@link PageRequest} with sort direction and properties applied for the first page.
*
* @param size the size of the page to be returned.
* @param direction must not be {@literal null}.
* @param properties must not be {@literal null}.
*/
public static CassandraPageRequest first(int size, Direction direction, String... properties) {
return first(size, Sort.by(direction, properties));
}
/**
* Validate the {@link Pageable} whether it can be used for querying. Valid pageables are either:
*
* - Unpaged
* - Request the first page
* - {@link CassandraPageRequest} with a {@link ByteBuffer paging state}
*
*
* @param pageable
* @throws IllegalArgumentException if the {@link Pageable} is not valid.
*/
public static void validatePageable(Pageable pageable) {
if (pageable.isUnpaged() || pageable.getPageNumber() == 0) {
return;
}
if (pageable instanceof CassandraPageRequest) {
CassandraPageRequest pageRequest = (CassandraPageRequest) pageable;
if (pageRequest.getPagingState() != null) {
return;
}
}
throw new IllegalArgumentException(
"Paging queries for pages other than the first one require a CassandraPageRequest with a valid paging state");
}
/**
* @return the {@link ByteBuffer paging state} for the current {@link CassandraPageRequest} or {@literal null} if the
* current {@link Pageable} represents the last page.
*/
@Nullable
public ByteBuffer getPagingState() {
if (this.pagingState == null) {
return null;
}
return this.pagingState.asReadOnlyBuffer();
}
/**
* Returns whether there's a next {@link Pageable} we can access from the current one. Will return {@literal false} in
* case the current {@link Pageable} already refers to the next page.
*
* @return {@literal true } if there's a next {@link Pageable} we can access from the current one.
*/
public boolean hasNext() {
return (getPagingState() != null && this.nextAllowed);
}
/* (non-Javadoc)
* @see org.springframework.data.domain.PageRequest#next()
*/
@Override
public CassandraPageRequest next() {
Assert.state(hasNext(), "Cannot create a next page request without a PagingState");
return new CassandraPageRequest(getPageNumber() + 1, getPageSize(), getSort(), getPagingState(), false);
}
/**
* Create a new {@link CassandraPageRequest} associated with {@link Sort} sort order.
*
* @param sort must not be {@literal null}.
* @return a new {@link CassandraPageRequest} associated with the given {@link Sort}.
* @since 2.1.13
*/
public CassandraPageRequest withSort(Sort sort) {
Assert.notNull(sort, "Sort must not be null");
return new CassandraPageRequest(this.getPageNumber(), this.getPageSize(), sort, getPagingState(), this.nextAllowed);
}
/* (non-Javadoc)
* @see org.springframework.data.domain.PageRequest#previous()
*/
@Override
public PageRequest previous() {
Assert.state(getPageNumber() < 2, "Cannot navigate to an intermediate page");
return super.previous();
}
/* (non-Javadoc)
* @see org.springframework.data.domain.PageRequest#equals(java.lang.Object)
*/
@Override
public boolean equals(@Nullable Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof CassandraPageRequest)) {
return false;
}
if (!super.equals(obj)) {
return false;
}
CassandraPageRequest that = (CassandraPageRequest) obj;
if (nextAllowed != that.nextAllowed) {
return false;
}
return (pagingState != null ? pagingState.equals(that.pagingState) : that.pagingState == null);
}
/* (non-Javadoc)
* @see org.springframework.data.domain.PageRequest#hashCode()
*/
@Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + (pagingState != null ? pagingState.hashCode() : 0);
result = 31 * result + (nextAllowed ? 1 : 0);
return result;
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return String.format("Cassandra page request [number: %d, size %d, sort: %s, paging state: %s]", getPageNumber(),
getPageSize(), getSort(), getPagingState());
}
}