com.almworks.jira.structure.api.forest.item

Class ManagerBackedItemForest

Object

ManagerBackedItemForest

All Implemented Interfaces:

ItemForest, RowRetriever

public class ManagerBackedItemForest
extends Object
implements ItemForest

Field Summary

Fields inherited from interface RowRetriever

IGNORE_MISSING_ROWS

Constructor Summary

Constructors

Constructor and Description
ManagerBackedItemForest(Forest forest, RowManager rowManager)
ManagerBackedItemForest(Forest forest, RowManager rowManager, ItemAccessMode defaultAccessMode)

Method Summary

Modifier and Type	Method and Description
Forest	getForest()
StructureRow	getRow(long rowId, ItemAccessMode access) Retrieves StructureRow with additional information about how the calling code is going to use method StructureRow.getItem(java.lang.Class<I>).
void	scanRows(LongIterable rows, boolean sorted, ItemAccessMode access, LongCollector missingCollector, Predicate<StructureRow> iteratee) Loads multiple rows by their IDs and calls iteratee with a StructureRow for each row ID in the input.
String	toString()

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface ItemForest

collectItemIds

Methods inherited from interface RowRetriever

collectIssueIds, collectIssueIds, getRow, reduceOverRows, scanAllExistingRows, scanAllExistingRows, scanAllExistingRows, scanAllRows, scanAllRows, scanAllRows, scanAllRows, scanRows, scanRows, scanRows

Constructor Detail

ManagerBackedItemForest

public ManagerBackedItemForest(@NotNull
                               Forest forest,
                               @NotNull
                               RowManager rowManager)

ManagerBackedItemForest

public ManagerBackedItemForest(@NotNull
                               Forest forest,
                               @NotNull
                               RowManager rowManager,
                               @Nullable
                               ItemAccessMode defaultAccessMode)

Method Detail

getForest

@NotNull
public Forest getForest()

Specified by:

getForest in interface ItemForest

getRow

@NotNull
public StructureRow getRow(long rowId,
                                    @NotNull
                                    ItemAccessMode access)
                             throws MissingRowException

Description copied from interface: RowRetriever

Retrieves StructureRow with additional information about how the calling code is going to use method StructureRow.getItem(java.lang.Class<I>). The implementation may be optimized according to the access parameter.

If row's item is invisible or does not exist, StructureRow is returned anyway, but StructureRow.getItem(java.lang.Class<I>) return null.

Specified by:

getRow in interface RowRetriever

Parameters:

rowId - row ID

access - defines how item object is going to be accessed

Returns:

row instance

Throws:

MissingRowException - if the specified row ID does not exist

See Also:

ItemAccessMode

scanRows

public void scanRows(@Nullable
                     LongIterable rows,
                     boolean sorted,
                     @NotNull
                     ItemAccessMode access,
                     @Nullable
                     LongCollector missingCollector,
                     @NotNull
                     Predicate<StructureRow> iteratee)
              throws MissingRowException

Description copied from interface: RowRetriever

Loads multiple rows by their IDs and calls iteratee with a StructureRow for each row ID in the input. Use this method whenever you need to read a potentially large amount of rows and the order of retrieval is not important.

For example, use scanRows to iterate through the whole forest to see if it has a generator row, or to process user input that has an array of row IDs.

The order in which iteratee is called is not guaranteed to be the same as the iteration order of rows. Likewise, missingCollector may receive row IDs out of order.

The implementation of iteratee must be reasonably fast and avoid taking locks or accessing long-running services. It's possible to call other RowRetriever methods inside iteratee.

It's possible to pass LongIterator as LongIterable - the iterator() method is guaranteed to be called only once.

Item access mode

You can choose an appropriate value for the access parameter based on what you're going to do with rows in the iteratee. This allows the provider of StructureRow instances to optimize how StructureRow.getItem(java.lang.Class<I>) method works.

Dealing with missing rows

If a row ID in the input stream does not correspond to an existing row, the behavior depends on whether the missingCollector parameter is set. If it's null, then the method will immediately throw a MissingRowException. If it's not null, the collector will be called with the missing row ID.

To simply ignore the missing rows, you can use RowRetriever.IGNORE_MISSING_ROWS collector or use one of the RowRetriever.scanAllExistingRows(com.almworks.integers.LongIterable, boolean, com.almworks.jira.structure.api.row.ItemAccessMode, java.util.function.Consumer<com.almworks.jira.structure.api.row.StructureRow>) methods.

Note that if the current user does not have access to a row, but the row itself exists, it's not considered missing.

Super-root

Note that normally a row retriever does not handle SuperRootRow in any special way, so it will be a case of a missing row. Some implementations may, however, support accessing the super-root.

Implementation notes

The default implementation is based on calling RowRetriever.getRow(long). Specific implementations should optimize this method for retrieving multiple rows at once.

Do not override other bulk scanning methods, unless that allows for additional optimization.

Specified by:

scanRows in interface RowRetriever

Parameters:

rows - row IDs of the rows to scan

sorted - if true, then the caller guarantees the row IDs to be sorted - this can be used for optimization

access - indicates how the getItem() method of the provided StructureRow is going to be used and allows to skip the access checking

missingCollector - a collector to receive non-existing row IDs, or null

iteratee - predicate to call for each resolved row; if it returns false, the iteration stops and the method returns

Throws:

MissingRowException - if a row was not found and missingCollector is null

See Also:

RowManager, ItemAccessMode

toString

public String toString()

Overrides:

toString in class Object