/*
* Copyright 2014-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.dynamodbv2.document.internal;
import static com.amazonaws.services.dynamodbv2.document.internal.InternalUtils.toItemList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.Page;
import com.amazonaws.services.dynamodbv2.document.QueryOutcome;
import com.amazonaws.services.dynamodbv2.document.spec.QuerySpec;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.QueryRequest;
import com.amazonaws.services.dynamodbv2.model.QueryResult;
class QueryPage extends Page<Item, QueryOutcome> {
private final AmazonDynamoDB client;
private final QuerySpec spec;
private final QueryRequest request;
private final int index;
private final Map<String, AttributeValue> lastEvaluatedKey;
public QueryPage(
AmazonDynamoDB client,
QuerySpec spec,
QueryRequest request,
int index,
QueryOutcome outcome) {
super(Collections.unmodifiableList(
toItemList(outcome.getQueryResult().getItems())),
outcome);
this.client = client;
this.spec = spec;
this.request = request;
this.index = index;
final Integer max = spec.getMaxResultSize();
final QueryResult result = outcome.getQueryResult();
final List<?> ilist = result.getItems();
final int size = ilist == null ? 0 : ilist.size();
if (max != null && (index + size) > max) {
this.lastEvaluatedKey = null;
} else {
this.lastEvaluatedKey = result.getLastEvaluatedKey();
}
}
@Override
public boolean hasNextPage() {
if (lastEvaluatedKey == null)
return false;
Integer max = spec.getMaxResultSize();
if (max == null)
return true;
return nextRequestLimit(max.intValue()) > 0;
}
private int nextRequestLimit(int max) {
int nextIndex = index + this.size();
return InternalUtils.minimum(
max - nextIndex,
spec.getMaxPageSize());
}
@Override
public Page<Item,QueryOutcome> nextPage() {
if (lastEvaluatedKey == null) {
throw new NoSuchElementException("No more pages");
}
final Integer max = spec.getMaxResultSize();
if (max != null) {
int nextLimit = nextRequestLimit(max.intValue());
if (nextLimit == 0)
throw new NoSuchElementException("No more pages");
request.setLimit(nextLimit);
}
request.setExclusiveStartKey(lastEvaluatedKey);
QueryResult result = client.query(request);
final int nextIndex = index + this.size();
return new QueryPage(client, spec, request, nextIndex,
new QueryOutcome(result));
}
}