org.apache.nifi.controller.repository

Interface ContentRepository

public interface ContentRepository

Defines the capabilities of a content repository. Append options are not available on the methods but a merge capability is provided which between that and creating new claims a merge is available.

Method Summary

Modifier and Type	Method and Description
void	cleanup() Performs any cleanup actions that may need to be taken upon system restart.
ContentClaim	clone(ContentClaim original, boolean lossTolerant) Clones the content for the given content claim and returns content claim of the new object
ContentClaim	create(boolean lossTolerant) Creates a new content claim
int	decrementClaimantCount(ContentClaim claim) Reduces the number of claimants for the given claim.
long	exportTo(ContentClaim claim, OutputStream destination) Exports the content of the given claim to the given destination.
long	exportTo(ContentClaim claim, OutputStream destination, long offset, long length) Exports a subset of the content of the given claim, starting at offset and copying length bytes, to the given destination.
long	exportTo(ContentClaim claim, Path destination, boolean append) Exports the content of the given claim to the given destination.
long	exportTo(ContentClaim claim, Path destination, boolean append, long offset, long length) Exports the content of the given claim to the given destination.
int	getClaimantCount(ContentClaim claim) Obtains the current number of claimants for the given claim
long	getContainerCapacity(String containerName)
Set<String>	getContainerNames()
long	getContainerUsableSpace(String containerName)
long	importFrom(InputStream content, ContentClaim claim) Imports content from the given stream creating a new content object and claim within the repository.
long	importFrom(Path content, ContentClaim claim) Imports content from the given path creating a new content object and claim within the repository.
int	incrementClaimaintCount(ContentClaim claim) Increments the number of claimants for the given claim
void	initialize(ResourceClaimManager claimManager) Initializes the Content Repository, providing to it the ContentClaimManager that is to be used for interacting with Content Claims
boolean	isAccessible(ContentClaim contentClaim)
long	merge(Collection<ContentClaim> claims, ContentClaim destination, byte[] header, byte[] footer, byte[] demarcator) Creates a new content item that is the merger in iteration order of all content for the given claims
void	purge() Purges the contents of the repository, as if the repository were newly created.
InputStream	read(ContentClaim claim) Provides access to the input stream for the given claim
boolean	remove(ContentClaim claim) Removes the content indicated by the given claim
void	shutdown() Shuts down the Content Repository, freeing any resources that may be held.
long	size(ContentClaim claim)
OutputStream	write(ContentClaim claim) Obtains an OutputStream to the content for the given claim.

Method Detail

initialize

void initialize(ResourceClaimManager claimManager)
         throws IOException

Initializes the Content Repository, providing to it the ContentClaimManager that is to be used for interacting with Content Claims

Parameters:

claimManager - to handle claims

Throws:

IOException - if unable to init

shutdown

void shutdown()

Shuts down the Content Repository, freeing any resources that may be held. This is called when an administrator shuts down NiFi.

getContainerNames

Set<String> getContainerNames()

Returns:

the names of all Containers that exist for this Content Repository

getContainerCapacity

long getContainerCapacity(String containerName)
                   throws IOException

Parameters:

containerName - name of container to check capacity on

Returns:

the maximum number of bytes that can be stored in the storage mechanism that backs the container with the given name

Throws:

IOException - if unable to check capacity

IllegalArgumentException - if no container exists with the given name

getContainerUsableSpace

long getContainerUsableSpace(String containerName)
                      throws IOException

Parameters:

containerName - to check space on

Returns:

the number of bytes available to be used used by the storage mechanism that backs the container with the given name

Throws:

IOException - if unable to check space

IllegalArgumentException - if no container exists with the given name

create

ContentClaim create(boolean lossTolerant)
             throws IOException

Creates a new content claim

Parameters:

lossTolerant - indicates whether the content for the new claim is loss tolerant. If true the repository might choose more volatile storage options which could increase performance for a tradeoff with reliability

Returns:

newly created claim

Throws:

IOException - if unable to create claim

incrementClaimaintCount

int incrementClaimaintCount(ContentClaim claim)

Increments the number of claimants for the given claim

Parameters:

claim - to increment

Returns:

the number of claimants after incrementing

getClaimantCount

int getClaimantCount(ContentClaim claim)

Obtains the current number of claimants for the given claim

Parameters:

claim - to get count of

Returns:

the number of claimants

decrementClaimantCount

int decrementClaimantCount(ContentClaim claim)

Reduces the number of claimants for the given claim. Even if the given claim is null or content cannot be found or removed no exception will be thrown.

Parameters:

claim - to decrement

Returns:

new claimant count for the given claim

remove

boolean remove(ContentClaim claim)

Removes the content indicated by the given claim

Parameters:

claim - to remove

Returns:

a boolean indicating whether or not the destruction of the claim was successful

clone

ContentClaim clone(ContentClaim original,
                   boolean lossTolerant)
            throws IOException

Clones the content for the given content claim and returns content claim of the new object

Parameters:

original - to clone

lossTolerant - if can be place in a loss tolerant repository

Returns:

new claim

Throws:

IOException - if an IO error occurs. Any content written to the new destination prior to the error will be destroyed

merge

long merge(Collection<ContentClaim> claims,
           ContentClaim destination,
           byte[] header,
           byte[] footer,
           byte[] demarcator)
    throws IOException

Creates a new content item that is the merger in iteration order of all content for the given claims

Parameters:

claims - the claims to merge which will be combined in order of collection iteration

destination - the claim to write the merged content to

header - if supplied will be prepended to the output

footer - if supplied will be appended to the output

demarcator - if supplied will be placed in between each merged object

Returns:

the size of the destination

Throws:

IOException - if unable to merge

IllegalArgumentException - if the given destination is included in the given claims

importFrom

long importFrom(Path content,
                ContentClaim claim)
         throws IOException

Imports content from the given path creating a new content object and claim within the repository.

Parameters:

content - to import from

claim - the claim to write imported content to

Returns:

the size of the claim

Throws:

IOException - if failure to read given content

importFrom

long importFrom(InputStream content,
                ContentClaim claim)
         throws IOException

Imports content from the given stream creating a new content object and claim within the repository.

Parameters:

content - to import from

claim - the claim to write imported content to

Returns:

the size of the claim

Throws:

IOException - if unable to read content

exportTo

long exportTo(ContentClaim claim,
              Path destination,
              boolean append)
       throws IOException

Exports the content of the given claim to the given destination.

Parameters:

claim - to export from

destination - where to export data

append - if true appends to the destination; false overwrites

Returns:

the size of the destination or the claim

Throws:

IOException - if an IO error occurs. The state of the content for the given destination is unknown and callers should consider whether they should clean up any partially created paths

exportTo

long exportTo(ContentClaim claim,
              Path destination,
              boolean append,
              long offset,
              long length)
       throws IOException

Exports the content of the given claim to the given destination.

Parameters:

claim - to export from

destination - where to export data

append - if true appends to the destination; false overwrites

offset - the offset at which the claim should start being copied

length - the number of bytes to copy

Returns:

the size of the destination or the claim

Throws:

IOException - if an IO error occurs. The state of the content for the given destination is unknown and callers should consider whether they should clean up any partially created paths

exportTo

long exportTo(ContentClaim claim,
              OutputStream destination)
       throws IOException

Exports the content of the given claim to the given destination.

Parameters:

claim - to export from

destination - where to export data

Returns:

the size of the claim

Throws:

IOException - if an IO error occurs.

exportTo

long exportTo(ContentClaim claim,
              OutputStream destination,
              long offset,
              long length)
       throws IOException

Exports a subset of the content of the given claim, starting at offset and copying length bytes, to the given destination.

Parameters:

claim - to export from

destination - where to export data

offset - the offset into the claim at which the copy should begin

length - the number of bytes to copy

Returns:

the number of bytes copied

Throws:

IOException - if an IO error occurs.

size

long size(ContentClaim claim)
   throws IOException

Parameters:

claim - to get size of

Returns:

size in bytes of content for given claim

Throws:

IOException - if size check failed

read

InputStream read(ContentClaim claim)
          throws IOException

Provides access to the input stream for the given claim

Parameters:

claim - to read from

Returns:

InputStream over the content of the given claim

Throws:

IOException - if unable to read

write

OutputStream write(ContentClaim claim)
            throws IOException

Obtains an OutputStream to the content for the given claim.

Parameters:

claim - to write to

Returns:

the stream to write to

Throws:

IOException - if unable to obtain stream

purge

void purge()

Purges the contents of the repository, as if the repository were newly created.

cleanup

void cleanup()

Performs any cleanup actions that may need to be taken upon system restart. For example, if content was partially written to the repository before the restart, the repository is given a chance to handle this data

isAccessible

boolean isAccessible(ContentClaim contentClaim)
              throws IOException

Parameters:

contentClaim - the Content Claim to check

Returns:

Returns a boolean indicating whether or not the content specified by the given claim can be read, regardless of whether the content has been archived or not. If the ContentRepository does not implement archiving capabilities, this method will return false

Throws:

IOException - if unable to determine accessibility