/* * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.yangtools.yang.data.api.schema.xpath; import com.google.common.annotations.Beta; import com.google.common.util.concurrent.ListenableFuture; import java.util.Optional; import java.util.concurrent.Future; import javax.annotation.Nonnull; import javax.xml.xpath.XPathExpressionException; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier; /** * Asynchronous interface to evaluation. It is functionally the same as an XPathExpression, but allows for asynchronous * execution of evaluation of the expression. * *
* FIXME: Whether or not the resulting XPathResult can perform blocking calls is up for grabs, but implementations are * definitely allowed to perform things like on-demand data transformation from foreign object and data models. * * @deprecated PREVIEW API. DO NOT IMPLEMENT YET AS THIS NEEDS TO BE VALIDATED FOR USE IN CLIENT APPLICATIONS. * APPLICATIONS WILLING TO USE THIS API PLEASE CONTACT * yangtools-dev. */ @Deprecated @Beta public interface LazyXPathExpression { /** * Evaluate this expression at the specified path in a document. If evaluation succeeds, it will return an * {@link XPathResult} at some point it the future. If it fails to match anything, it {@link Future#get()} will * return {@link Optional#empty()}. * *
* FIXME: The amount of overhead an implementation can incur on the user as data from the resulting
* {@link XPathResult} is being accessed is left UNDEFINED.
* Specifically, the user is expected to store each result returned directly or indirectly in a local
* variable instead of repeated calls to the result's methods, as these may incur CPU processing overhead.
* Furthermore all method invocations can throw {@link LazyXPathExpressionException}, which the users are
* expected to handle gracefully. RESILIENT USERS ARE EXPECTED TO CATCH {@link LazyXPathExpressionException}
* AND RECOVER IN THE SAME MANNER THEY WOULD IF AN {@link XPathExpressionException} WOULD HAVE BEEN THROWN.
* [ FIXME: would it be appropriate to allow implementations to SneakyThrow {@link XPathExpressionException}
* and not introduce a RuntimeExpcetion ? ]
*
* @param document {@link XPathDocument} on which evaluation should take place
* @param path Path to the node on which to evaluate the expression
* @return An optional {@link XPathResult}
* @throws NullPointerException if any of the arguments are null
* @throws IllegalArgumentException if the path does not match the path at which this expression was compiled
*/
ListenableFuture