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<?php
/*
* Copyright 2016 Google LLC
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
namespace Google\ApiCore;
use Generator;
use Google\Protobuf\Internal\Message;
use Google\Protobuf\Internal\MapField;
use IteratorAggregate;
/**
* A Page object wraps an API list method response and provides methods
* to retrieve additional pages using the page token.
*/
class Page implements IteratorAggregate
{
const FINAL_PAGE_TOKEN = "";
private $call;
private $callable;
private $options;
private $pageStreamingDescriptor;
private $pageToken;
private $response;
/**
* Page constructor.
*
* @param Call $call
* @param array $options
* @param callable $callable
* @param PageStreamingDescriptor $pageStreamingDescriptor
* @param Message $response
*/
public function __construct(
Call $call,
array $options,
callable $callable,
PageStreamingDescriptor $pageStreamingDescriptor,
Message $response
) {
$this->call = $call;
$this->options = $options;
$this->callable = $callable;
$this->pageStreamingDescriptor = $pageStreamingDescriptor;
$this->response = $response;
$requestPageTokenGetMethod = $this->pageStreamingDescriptor->getRequestPageTokenGetMethod();
$this->pageToken = $this->call->getMessage()->$requestPageTokenGetMethod();
}
/**
* Returns true if there are more pages that can be retrieved from the
* API.
*
* @return bool
*/
public function hasNextPage()
{
return strcmp($this->getNextPageToken(), Page::FINAL_PAGE_TOKEN) != 0;
}
/**
* Returns the next page token from the response.
*
* @return string
*/
public function getNextPageToken()
{
$responsePageTokenGetMethod = $this->pageStreamingDescriptor->getResponsePageTokenGetMethod();
return $this->getResponseObject()->$responsePageTokenGetMethod();
}
/**
* Retrieves the next Page object using the next page token.
*
* @param int|null $pageSize
* @throws ValidationException if there are no pages remaining, or if pageSize is supplied but
* is not supported by the API
* @throws ApiException if the call to fetch the next page fails.
* @return Page
*/
public function getNextPage($pageSize = null)
{
if (!$this->hasNextPage()) {
throw new ValidationException(
'Could not complete getNextPage operation: ' .
'there are no more pages to retrieve.'
);
}
$oldRequest = $this->getRequestObject();
$requestClass = get_class($oldRequest);
$newRequest = new $requestClass();
$newRequest->mergeFrom($oldRequest);
$requestPageTokenSetMethod = $this->pageStreamingDescriptor->getRequestPageTokenSetMethod();
$newRequest->$requestPageTokenSetMethod($this->getNextPageToken());
if (isset($pageSize)) {
if (!$this->pageStreamingDescriptor->requestHasPageSizeField()) {
throw new ValidationException(
'pageSize argument was defined, but the method does not ' .
'support a page size parameter in the optional array argument'
);
}
$requestPageSizeSetMethod = $this->pageStreamingDescriptor->getRequestPageSizeSetMethod();
$newRequest->$requestPageSizeSetMethod($pageSize);
}
$this->call = $this->call->withMessage($newRequest);
$callable = $this->callable;
$response = $callable(
$this->call,
$this->options
)->wait();
return new Page(
$this->call,
$this->options,
$this->callable,
$this->pageStreamingDescriptor,
$response
);
}
/**
* Return the number of elements in the response.
*
* @return int
*/
public function getPageElementCount()
{
$resourcesGetMethod = $this->pageStreamingDescriptor->getResourcesGetMethod();
return count($this->getResponseObject()->$resourcesGetMethod());
}
/**
* Return an iterator over the elements in the response.
*
* @return Generator
*/
public function getIterator()
{
$resourcesGetMethod = $this->pageStreamingDescriptor->getResourcesGetMethod();
$items = $this->getResponseObject()->$resourcesGetMethod();
foreach ($items as $key => $element) {
if ($items instanceof MapField) {
yield $key => $element;
} else {
yield $element;
}
}
}
/**
* Return an iterator over Page objects, beginning with this object.
* Additional Page objects are retrieved lazily via API calls until
* all elements have been retrieved.
*
* @return Generator|Page[]
* @throws ValidationException
* @throws ApiException
*/
public function iteratePages()
{
$currentPage = $this;
yield $this;
while ($currentPage->hasNextPage()) {
$currentPage = $currentPage->getNextPage();
yield $currentPage;
}
}
/**
* Gets the request object used to generate the Page.
*
* @return mixed|Message
*/
public function getRequestObject()
{
return $this->call->getMessage();
}
/**
* Gets the API response object.
*
* @return mixed|Message
*/
public function getResponseObject()
{
return $this->response;
}
/**
* Returns a collection of elements with a fixed size set by
* the collectionSize parameter. The collection will only contain
* fewer than collectionSize elements if there are no more
* pages to be retrieved from the server.
*
* NOTE: it is an error to call this method if an optional parameter
* to set the page size is not supported or has not been set in the
* API call that was used to create this page. It is also an error
* if the collectionSize parameter is less than the page size that
* has been set.
*
* @param $collectionSize int
* @throws ValidationException if a FixedSizeCollection of the specified size cannot be constructed
* @return FixedSizeCollection
*/
public function expandToFixedSizeCollection($collectionSize)
{
if (!$this->pageStreamingDescriptor->requestHasPageSizeField()) {
throw new ValidationException(
"FixedSizeCollection is not supported for this method, because " .
"the method does not support an optional argument to set the " .
"page size."
);
}
$request = $this->getRequestObject();
$pageSizeGetMethod = $this->pageStreamingDescriptor->getRequestPageSizeGetMethod();
$pageSize = $request->$pageSizeGetMethod();
if (is_null($pageSize)) {
throw new ValidationException(
"Error while expanding Page to FixedSizeCollection: No page size " .
"parameter found. The page size parameter must be set in the API " .
"optional arguments array, and must be less than the collectionSize " .
"parameter, in order to create a FixedSizeCollection object."
);
}
if ($pageSize > $collectionSize) {
throw new ValidationException(
"Error while expanding Page to FixedSizeCollection: collectionSize " .
"parameter is less than the page size optional argument specified in " .
"the API call. collectionSize: $collectionSize, page size: $pageSize"
);
}
return new FixedSizeCollection($this, $collectionSize);
}
}
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