Package org.eclipse.aether.internal.impl.synccontext.named

Class HashingNameMapper

java.lang.Object

org.eclipse.aether.internal.impl.synccontext.named.HashingNameMapper

All Implemented Interfaces:

NameMapper

public class HashingNameMapper
extends Object
implements NameMapper

Wrapping NameMapper, that wraps another NameMapper and hashes resulting strings. It makes use of fact that (proper) Hash will create unique fixed length string for each different input string (so injection still stands). This mapper produces file system friendly names. Supports different "depths" (0-4 inclusive) where the name will contain 0 to 4 level deep directories.

This mapper is usable in any scenario, but intent was to produce more "compact" name mapper for file locking.

Since:

1.9.0

Constructor Summary

Constructors

Constructor	Description
HashingNameMapper(NameMapper delegate)

Method Summary

Modifier and Type	Method	Description
boolean	isFileSystemFriendly()	Returns true if lock names returned by this lock name mapper are file system friendly, can be used as file names and paths.
Collection<String>	nameLocks(org.eclipse.aether.RepositorySystemSession session, Collection<? extends org.eclipse.aether.artifact.Artifact> artifacts, Collection<? extends org.eclipse.aether.metadata.Metadata> metadatas)	Creates (opaque) names for passed in artifacts and metadata.

Methods inherited from class java.lang.Object

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

Constructor Details

HashingNameMapper

public HashingNameMapper(NameMapper delegate)

Method Details

isFileSystemFriendly

public boolean isFileSystemFriendly()

Description copied from interface: NameMapper

Returns true if lock names returned by this lock name mapper are file system friendly, can be used as file names and paths.

Specified by:

isFileSystemFriendly in interface NameMapper

nameLocks

public Collection<String> nameLocks(org.eclipse.aether.RepositorySystemSession session,
 Collection<? extends org.eclipse.aether.artifact.Artifact> artifacts,
 Collection<? extends org.eclipse.aether.metadata.Metadata> metadatas)

Description copied from interface: NameMapper

Creates (opaque) names for passed in artifacts and metadata. Returned collection has max size of sum of the passed in artifacts and metadata collections, or less. If an empty collection is returned, there will be no locking happening. Never returns null. The resulting collection MUST BE "stable" (always sorted by same criteria) to avoid deadlocks by acquiring locks in same order, essentially disregarding the order of the input collections.

There is no requirement of any kind of "parity" between input element count (sum of two collections, that is) and output collection size, just the returned upper size limit is defined (sum of the passed in two collections size). If returned collection is empty, no locking will happen, if single element, one lock will be used, if two then two named locks will be used etc.

Note: name mapper must not use same string for artifacts and metadata, so even the simplest possible implementation like StaticNameMapper uses two different static strings.

Specified by:

nameLocks in interface NameMapper