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83 lines
2.5 KiB
Java
83 lines
2.5 KiB
Java
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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package org.mozilla.gecko.sync.repositories;
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import java.util.Iterator;
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/**
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* Our hacky version of transactional semantics. The goal is to prevent
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* the following situation:
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*
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* * AAA is not modified locally.
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* * A modified AAA is downloaded during the storing phase. Its local
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* timestamp is advanced.
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* * The direction of syncing changes, and AAA is now uploaded to the server.
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*
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* The following situation should still be supported:
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*
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* * AAA is not modified locally.
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* * A modified AAA is downloaded and merged with the local AAA.
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* * The merged AAA is uploaded to the server.
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*
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* As should:
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*
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* * AAA is modified locally.
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* * A modified AAA is downloaded, and discarded or merged.
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* * The current version of AAA is uploaded to the server.
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*
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* We achieve this by tracking GUIDs during the storing phase. If we
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* apply a record such that the local copy is substantially the same
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* as the record we just downloaded, we add it to a list of records
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* to avoid uploading. The definition of "substantially the same"
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* depends on the particular repository. The only consideration is "do we
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* want to upload this record in this sync?".
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*
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* Note that items are removed from this list when a fetch that
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* considers them for upload completes successfully. The entire list
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* is discarded when the session is completed.
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*
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* This interface exposes methods to:
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*
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* * During a store, recording that a record has been stored, and should
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* thus not be returned in subsequent fetches;
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* * During a fetch, checking whether a record should be returned.
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*
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* In the future this might also grow self-persistence.
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*
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* See also RepositorySession.trackRecord.
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*
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* @author rnewman
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*
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*/
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public interface StoreTracker {
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/**
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* @param guid
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* The GUID of the item to track.
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* @return
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* Whether the GUID was a newly tracked value.
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*/
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public boolean trackRecordForExclusion(String guid);
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/**
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* @param guid
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* The GUID of the item to check.
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* @return
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* true if the item is already tracked.
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*/
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public boolean isTrackedForExclusion(String guid);
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/**
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*
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* @param guid
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* @return true if the specified GUID was removed from the tracked set.
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*/
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public boolean untrackStoredForExclusion(String guid);
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public RecordFilter getFilter();
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public Iterator<String> recordsTrackedForExclusion();
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}
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