Package org.eclipse.emf.spi.cdo

Class DefaultCDOMerger

java.lang.Object
org.eclipse.emf.spi.cdo.DefaultCDOMerger
All Implemented Interfaces:
CDOMerger, CDOMergerBaseAware
Direct Known Subclasses:
DefaultCDOMerger.PerFeature
public class DefaultCDOMerger extends Object implements CDOMergerBaseAware
Default three-way merger for CDO change sets.

The first (target) change set describes the current branch or transaction into which the result will be applied. In CDOMergingConflictResolver this is the local transaction history. The second (source) change set describes the branch or repository history being merged.

Ordinary conflict-resolution histories share one start state. Automatic branch remerge can instead select different source and target bases. The branch transaction path therefore supplies both original base providers plus the actual result base. The semantic many-valued merger preserves that causal asymmetry so occurrences absent from one side's base are treated as unobserved rather than synthesized as removals. The richer branch/remerge entry point also normalizes every returned NEW, CHANGED, and DETACHED goal to the selected result base; CDOTransactionImpl.applyChangeSet() subsequently reconciles that goal with the actual target state.

CDO's internal producers retain the revision providers needed by the semantic many-valued merger. That richer call-local context provides full base values to distinguish equal list occurrences and the base set-state of unsettable features without storing repository/session state on this reusable merger instance.

Since:
3.0
Author:
Eike Stepper

  • Constructor Details

  • Method Details

    • getResolutionPreference

      public final DefaultCDOMerger.ResolutionPreference getResolutionPreference()
      Since:
      4.2

    • getListOrdering

      public CDOCommonRepository.ListOrdering getListOrdering()
      Since:
      4.6

    • getResult

      public CDOChangeSetData getResult()

    • getConflicts

      public Map<CDOID,DefaultCDOMerger.Conflict> getConflicts()

    • merge

      public CDOChangeSetData merge(CDOChangeSet target, CDOChangeSet source) throws CDOMerger.ConflictException
      Description copied from interface: CDOMerger
      Calculates the changes between a source change set and a target change set and returns the result relative to their common ancestor.
      Specified by:
      merge in interface CDOMerger
      Throws:
      CDOMerger.ConflictException

    • merge

      public CDOChangeSetData merge(CDOChangeSet target, CDOChangeSet source, CDORevisionProvider targetBaseProvider, CDORevisionProvider sourceBaseProvider, CDORevisionProvider resultBaseProvider) throws CDOMerger.ConflictException
      Merges branch/remerge change sets while preserving their independently selected source and target bases.

      Automatic remerge can legitimately produce list histories with different origin sizes because each history starts at the base that side actually observed. Reconstructing endpoint snapshots relative to the result base would turn an occurrence that one side never observed into a synthetic REMOVE. Instead the original executable histories are retained and the three base providers are propagated to the semantic many-valued merger.

      The ordinary two-argument merge(CDOChangeSet, CDOChangeSet) contract is retained for callers whose two change sets already share their merge base.

      Specified by:
      merge in interface CDOMergerBaseAware
      Parameters:
      target - the target change set selected by the branch merge calculation.
      source - the source change set selected by the branch merge calculation.
      targetBaseProvider - the revision state from which target starts.
      sourceBaseProvider - the revision state from which source starts.
      resultBaseProvider - the revision state relative to which every returned NEW, CHANGED, or DETACHED goal is defined.
      Returns:
      the merged change-set data relative to resultBaseProvider.
      Throws:
      CDOMerger.ConflictException - if the configured merger semantics cannot resolve all conflicts.
      Since:
      4.30

    • merge

      protected boolean merge(Object targetData, Object sourceData)

    • merge

      protected boolean merge(Object targetData, Object sourceData, CDORevision ancestorRevision)
      Merges the data for one object with the full common-ancestor revision when the producing call path retained it. The extra revision is an internal execution context; it does not widen the public CDOMerger contract.
      Since:
      4.30

    • merge

      protected boolean merge(Object targetData, Object sourceData, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision sourceBaseRevision)
      Merges one object's data with the result, target, and source base revisions needed by asymmetric branch remerge. Existing extenders remain on the common-ancestor overload unless they explicitly consume the richer context.
      Since:
      4.30

    • merge

      protected boolean merge(Object targetData, Object sourceData, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision sourceBaseRevision, CDORevision targetEndRevision, CDORevision sourceEndRevision)
      Merges one object's data while keeping every returned goal relative to resultBaseRevision. NEW and DETACHED classifications are first normalized to that base. CHANGED histories keep their own causal bases so semantic list merging does not lose unobserved-occurrence information.
      Since:
      4.30

    • addedInTarget

      protected Object addedInTarget(CDORevision revision)

    • addedInSource

      protected Object addedInSource(CDORevision revision)

    • addedInSourceAndTarget

      protected Object addedInSourceAndTarget(CDORevision targetRevision, CDORevision sourceRevision)

    • changedInTarget

      protected Object changedInTarget(CDORevisionDelta delta)

    • detachedInTarget

      protected Object detachedInTarget(CDOID id)

    • changedInTarget

      protected Object changedInTarget(CDORevisionDelta delta, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision sourceBaseRevision, CDORevision targetEndRevision)
      Resolves a one-sided target change as a goal relative to the actual result base.

      The base implementation treats the selected target endpoint as the complete object-level goal. DefaultCDOMerger.PerFeature refines this behavior so unchanged features stay unobserved and many-valued changes retain occurrence semantics.

      Since:
      4.30

    • changedInSource

      protected Object changedInSource(CDORevisionDelta delta)

    • changedInSource

      protected Object changedInSource(CDORevisionDelta delta, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision sourceBaseRevision, CDORevision sourceEndRevision)
      Resolves a one-sided source change as a goal relative to the actual result base.

      The base implementation treats the selected source endpoint as the complete object-level goal. DefaultCDOMerger.PerFeature refines this behavior so unchanged features stay unobserved and many-valued changes retain occurrence semantics.

      Since:
      4.30

    • detachedInSource

      protected Object detachedInSource(CDOID id)

    • detachedInSourceAndTarget

      protected Object detachedInSourceAndTarget(CDOID id)

    • changedInSourceAndTarget

      protected Object changedInSourceAndTarget(CDORevisionDelta targetDelta, CDORevisionDelta sourceDelta)

    • changedInSourceAndTarget

      protected Object changedInSourceAndTarget(CDORevisionDelta targetDelta, CDORevisionDelta sourceDelta, CDORevision ancestorRevision)
      Resolves concurrent revision changes with an optional full common-ancestor revision. Subclasses that need only deltas retain the established two-argument hook; semantic many-valued merging overrides this overload.
      Since:
      4.30

    • changedInSourceAndTarget

      protected Object changedInSourceAndTarget(CDORevisionDelta targetDelta, CDORevisionDelta sourceDelta, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision sourceBaseRevision)
      Resolves concurrent revision changes with explicit asymmetric branch/remerge base revisions.
      Since:
      4.30

    • changedInSourceAndDetachedInTarget

      protected Object changedInSourceAndDetachedInTarget(CDORevisionDelta sourceDelta)

    • changedInTargetAndDetachedInSource

      protected Object changedInTargetAndDetachedInSource(CDORevisionDelta targetDelta)

    • changedInSourceAndDetachedInTarget

      protected Object changedInSourceAndDetachedInTarget(CDORevisionDelta sourceDelta, CDORevision resultBaseRevision, CDORevision sourceBaseRevision, CDORevision sourceEndRevision)
      Resolves source-change versus target-detach as a result-base-relative goal.
      Since:
      4.30

    • changedInTargetAndDetachedInSource

      protected Object changedInTargetAndDetachedInSource(CDORevisionDelta targetDelta, CDORevision resultBaseRevision, CDORevision targetBaseRevision, CDORevision targetEndRevision)
      Resolves target-change versus source-detach as a result-base-relative goal.
      Since:
      4.30

    • getTargetMap

      protected Map<CDOID,Object> getTargetMap()

    • getSourceMap

      protected Map<CDOID,Object> getSourceMap()