Package org.opencms.db.generic

Class CmsDbStorage

java.lang.Object

org.opencms.db.generic.CmsDbStorage

All Implemented Interfaces:

AutoCloseable, I_CmsDbStorage, I_CmsStorage

Direct Known Subclasses:

CmsDbStorage, CmsDbStorage, CmsDbStorage, CmsDbStorage, CmsDbStorage, CmsDbStorage, CmsDbStorage

public class CmsDbStorage
extends Object
implements I_CmsDbStorage

Database backend for the OpenCms deduplicating media storage engine (DMSE).

This implementation stores binary content in a specialized table (CMS_STORAGE), using a unique hash for deduplication. It ensures that identical files are only stored once physically.

See Also:

• CmsStorageManager

Field Summary

Fields

Modifier and Type	Field	Description
protected final CmsSqlManager	m_sqlManager	The SQL manager to execute database queries.

Fields inherited from interface org.opencms.db.storage.I_CmsDbStorage

STORAGE_TYPE

Constructor Summary

Constructors

Constructor	Description
CmsDbStorage(CmsSqlManager sqlManager)	Public constructor.

Method Summary

Modifier and Type	Method	Description
void	deleteContent(CmsDbContext dbc, String hash)	Deletes the content from the storage if applicable.
String	getStorageIdentifier()	Returns the stable storage identifier stored in the VFS content tables.
byte[]	loadContent(CmsDbContext dbc, String hash)	Loads the actual binary content.
void	loadContentFrom(CmsDbContext dbc, String hash, I_CmsFileContentStreamHandler handler)	Loads the actual binary content and passes it to the given input stream handler.
void	loadContentTo(CmsDbContext dbc, String hash, OutputStream out)	Loads the actual binary content into the given output stream.
void	storeContent(CmsDbContext dbc, String hash, byte[] content)	Stores the given content.
void	validateAvailable(CmsDbContext dbc)	Validates that the storage backend is available for read and write operations.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.opencms.db.storage.I_CmsStorage

close

Field Details

m_sqlManager

protected final CmsSqlManager m_sqlManager

The SQL manager to execute database queries.

Constructor Details

CmsDbStorage

public CmsDbStorage(CmsSqlManager sqlManager)

Public constructor.

Parameters:

sqlManager - the SQL manager to use

Method Details

deleteContent

public void deleteContent(CmsDbContext dbc,
 String hash)
                   throws Exception

Description copied from interface: I_CmsStorage

Deletes the content from the storage if applicable.

Specified by:

deleteContent in interface I_CmsStorage

Parameters:

dbc - the database context

hash - the SHA-512 content hash

Throws:

Exception - if the deletion in the external storage fails

See Also:

• I_CmsStorage.deleteContent(org.opencms.db.CmsDbContext, java.lang.String)

getStorageIdentifier

public String getStorageIdentifier()

Description copied from interface: I_CmsStorage

Returns the stable storage identifier stored in the VFS content tables.

The identifier is the configured backend id, for example media or archive. The database storage uses the reserved backend id db. The identifier must not depend on mutable connection details such as paths, endpoints, or bucket names.

Specified by:

getStorageIdentifier in interface I_CmsStorage

Returns:

the stable storage identifier

See Also:

• I_CmsStorage.getStorageIdentifier()

loadContent

public byte[] loadContent(CmsDbContext dbc,
 String hash)
                   throws Exception

Description copied from interface: I_CmsStorage

Loads the actual binary content.

Specified by:

loadContent in interface I_CmsStorage

Parameters:

dbc - the database context

hash - the SHA-512 content hash

Returns:

the actual binary file content

Throws:

Exception - if the content cannot be retrieved

See Also:

• I_CmsStorage.loadContent(org.opencms.db.CmsDbContext, java.lang.String)

loadContentFrom

public void loadContentFrom(CmsDbContext dbc,
 String hash,
 I_CmsFileContentStreamHandler handler)
                     throws Exception

Description copied from interface: I_CmsStorage

Loads the actual binary content and passes it to the given input stream handler.

This default implementation keeps custom storage implementations source compatible by falling back to I_CmsStorage.loadContent(CmsDbContext, String).

Specified by:

loadContentFrom in interface I_CmsStorage

Parameters:

dbc - the database context

hash - the SHA-512 content hash

handler - the stream handler

Throws:

Exception - if the content cannot be retrieved or handled

See Also:

• I_CmsStorage.loadContentFrom(CmsDbContext, String, I_CmsFileContentStreamHandler)

loadContentTo

public void loadContentTo(CmsDbContext dbc,
 String hash,
 OutputStream out)
                   throws Exception

Description copied from interface: I_CmsStorage

Loads the actual binary content into the given output stream.

This default implementation keeps custom storage implementations source compatible by falling back to I_CmsStorage.loadContent(CmsDbContext, String).

Specified by:

loadContentTo in interface I_CmsStorage

Parameters:

dbc - the database context

hash - the SHA-512 content hash

out - the output stream to write to

Throws:

Exception - if the content cannot be retrieved or written

See Also:

• I_CmsStorage.loadContentTo(CmsDbContext, String, OutputStream)

storeContent

public void storeContent(CmsDbContext dbc,
 String hash,
 byte[] content)
                  throws Exception

Description copied from interface: I_CmsStorage

Stores the given content.

Specified by:

storeContent in interface I_CmsStorage

Parameters:

dbc - the database context

hash - the SHA-512 content hash

content - the actual binary data to store

Throws:

Exception - if the storage operation fails

See Also:

• I_CmsStorage.storeContent(org.opencms.db.CmsDbContext, java.lang.String, byte[])

validateAvailable

public void validateAvailable(CmsDbContext dbc)
                       throws Exception

Description copied from interface: I_CmsStorage

Validates that the storage backend is available for read and write operations.

This method is called during startup for configured storage backends. Implementations should perform a lightweight roundtrip which verifies the required prerequisites for storing content.

Specified by:

validateAvailable in interface I_CmsStorage

Parameters:

dbc - the database context

Throws:

Exception - if the storage backend is not available

See Also:

• I_CmsStorage.validateAvailable(org.opencms.db.CmsDbContext)