StorageManager (MMBase 1.9-SNAPSHOT

All Known Implementing Classes:

DatabaseStorageManager, InformixStorageManager, PostgresqlLargeObjectStorageManager, RelationalDatabaseStorageManager, ViewDatabaseStorageManager
```
public interface StorageManager<SMF extends StorageManagerFactory>
```
The StorageManager interface defines how to access a storage device. It contains methods that can be used to query the storage, insert, update, or remove objects, or to change object definitions (adding fields, etc.).

Since:

MMBase-1.7

Version:

$Id$

Author:

Pierre van Rooden

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`beginTransaction()` Starts a transaction on this StorageManager instance.
`void`	`change(CoreField field)` Changes a field to the storage of this builder.
`void`	`change(MMObjectBuilder builder)` Changes the storage of a builder to match its new configuration.
`void`	`change(MMObjectNode node)` Commit this node to the specified builder.
`void`	`commit()` Closes any transaction that was started and commits all changes.
`void`	`create()` Create the basic elements for this storage
`void`	`create(CoreField field)` Creates a field and adds it to the storage of this builder.
`void`	`create(MMObjectBuilder builder)` Create a storage element to store the specified builder's objects.
`int`	`create(MMObjectNode node)` This method creates a new object in the storage, and registers the change.
`int`	`createKey()` Gives an unique number for a new node, to be inserted in the storage.
`void`	`delete(CoreField field)` Deletes a field from the storage of this builder.
`void`	`delete(MMObjectBuilder builder)` Drops the storage of this builder.
`void`	`delete(MMObjectNode node)` Delete a node
`boolean`	`exists()` Determine if the basic storage elements exist Basic storage elements include the 'object' storage (where all objects and their types are registered).
`boolean`	`exists(MMObjectBuilder builder)` Determine if a storage element exists for storing the given builder's objects
`byte[]`	`getBinaryValue(MMObjectNode node, CoreField field)` Retrieve a large binary object (byte array) for a specified object field.
`InputStream`	`getInputStreamValue(MMObjectNode node, CoreField field)`
`MMObjectNode`	`getNode(MMObjectBuilder builder, int number)` Select a node from a specified builder
`int`	`getNodeType(int number)` Returns the nodetype for a specified nodereference
`String`	`getStringValue(MMObjectNode node, CoreField field)` Retrieve a large text for a specified object field.
`double`	`getVersion()` Returns the version of this factory implementation.
`void`	`init(SMF factory)` Initializes the manager.
`boolean`	`isNull(MMObjectNode node, CoreField field)` Checks for null values for a field from the storage of this builder.
`boolean`	`rollback()` Cancels any transaction that was started and rollback changes if possible.
`int`	`setNodeType(MMObjectNode node, MMObjectBuilder builder)`
`int`	`size()` Return the total number of objects in the storage
`int`	`size(MMObjectBuilder builder)` Return the number of objects of a builder in the storage

- Method Detail
  - getVersion
```
double getVersion()
```
    Returns the version of this factory implementation. The factory uses this number to verify whether it can handle storage configuration files that list version requirements.
    
    Returns:
    
    the version as an integer
  - init
```
void init(SMF factory)
   throws StorageException
```
    Initializes the manager. Called by a StorageManagerFactory when instantiating the manager with the getStorageManager() method.
    
    Parameters:
    
    factory - the StorageManagerFactory instance that created this storage manager.
    
    Throws:
    
    StorageConfigurationException - if the initialization failed
    
    StorageException
  - beginTransaction
```
void beginTransaction()
               throws StorageException
```
    Starts a transaction on this StorageManager instance. All commands passed to the instance will be treated as being in this transaction. If transactions are not supported by the storage, no actual storage transaction is started, but the code continues as if it has.
    
    Throws:
    
    StorageException - if the transaction could not be created
  - commit
```
void commit()
     throws StorageException
```
    Closes any transaction that was started and commits all changes. If transactions are not supported by the storage, nothing really happens (as changes are allready committed), but the code continues as if it has.
    
    Throws:
    
    StorageException - if a transaction is not currently active, or an error occurred while committing
  - rollback
```
boolean rollback()
          throws StorageException
```
    Cancels any transaction that was started and rollback changes if possible. If transactions are not supported by the storage, nothing really happens (as changes are allready committed), but the code continues as if it has (through in that case it will return false).
    
    Returns:
    
    true if changes were rolled back, false if the transaction was canceled but the storage does not support rollback
    
    Throws:
    
    StorageException - if a transaction is not currently active, or an error occurred during rollback
  - createKey
```
int createKey()
       throws StorageException
```
    Gives an unique number for a new node, to be inserted in the storage. This method should work with multiple mmbases
    
    Returns:
    
    unique number
    
    Throws:
    
    StorageException
  - getStringValue
```
String getStringValue(MMObjectNode node,
                      CoreField field)
               throws StorageException
```
    Retrieve a large text for a specified object field. Implement this method to allow for optimization of storing and retrieving large texts.
    
    Parameters:
    
    node - the node to retrieve the text from
    
    field - the Type of the field to retrieve
    
    Returns:
    
    the retrieved text
    
    Throws:
    
    StorageException - if an error occurred while retrieving the text value
  - getBinaryValue
```
byte[] getBinaryValue(MMObjectNode node,
                      CoreField field)
               throws StorageException
```
    Retrieve a large binary object (byte array) for a specified object field. Implement this method to allow for optimization of storing and retrieving binary objects.
    
    Parameters:
    
    node - the node to retrieve the byte array from
    
    field - the CoreField of the field to retrieve
    
    Returns:
    
    the retrieved byte array
    
    Throws:
    
    StorageException - if an error occurred while retrieving the binary value
  - getInputStreamValue
```
InputStream getInputStreamValue(MMObjectNode node,
                                CoreField field)
                         throws StorageException
```
    Throws:
    
    StorageException
    
    Since:
    
    MMBase-1.8
  - create
```
int create(MMObjectNode node)
    throws StorageException
```
    This method creates a new object in the storage, and registers the change. Only fields with states of DBSTATE_PERSISTENT or DBSTATE_SYSTEM are stored.
    
    Parameters:
    
    node - The node to insert
    
    Returns:
    
    The (new) number for this node, or -1 if an error occurs.
    
    Throws:
    
    StorageException - if an error occurred during insert
  - change
```
void change(MMObjectNode node)
     throws StorageException
```
    Commit this node to the specified builder.
    
    Parameters:
    
    node - The node to commit
    
    Throws:
    
    StorageException - if an error occurred during commit
  - delete
```
void delete(MMObjectNode node)
     throws StorageException
```
    Delete a node
    
    Parameters:
    
    node - The node to delete
    
    Throws:
    
    StorageException - if an error occurred during delete
  - setNodeType
```
int setNodeType(MMObjectNode node,
                MMObjectBuilder builder)
         throws StorageException
```
    Throws:
    
    StorageException
    
    Since:
    
    MMBase-1.9.1
  - getNode
```
MMObjectNode getNode(MMObjectBuilder builder,
                     int number)
              throws StorageException
```
    Select a node from a specified builder
    
    Parameters:
    
    builder - The builder to select from
    
    number - the number of the node
    
    Returns:
    
    the MMObjectNode that was found, or null f it doesn't exist
    
    Throws:
    
    StorageException - if an error occurred during the get
  - getNodeType
```
int getNodeType(int number)
         throws StorageException
```
    Returns the nodetype for a specified nodereference
    
    Parameters:
    
    number - the number of the node
    
    Returns:
    
    int the object type or -1 if not found
    
    Throws:
    
    StorageException - if an error occurred during selection
  - create
```
void create(MMObjectBuilder builder)
     throws StorageException
```
    Create a storage element to store the specified builder's objects.
    
    Parameters:
    
    builder - the builder to create the storage element for
    
    Throws:
    
    StorageException - if an error occurred during the creation of the storage element
  - create
```
void create()
     throws StorageException
```
    Create the basic elements for this storage
    
    Throws:
    
    StorageException - if an error occurred during the creation of the object storage
  - change
```
void change(MMObjectBuilder builder)
     throws StorageException
```
    Changes the storage of a builder to match its new configuration.
    
    Parameters:
    
    builder - the builder whose storage to change
    
    Throws:
    
    StorageException
  - delete
```
void delete(MMObjectBuilder builder)
     throws StorageException
```
    Drops the storage of this builder.
    
    Parameters:
    
    builder - the builder whose storage to drop
    
    Throws:
    
    StorageException
  - exists
```
boolean exists(MMObjectBuilder builder)
        throws StorageException
```
    Determine if a storage element exists for storing the given builder's objects
    
    Parameters:
    
    builder - the builder to check
    
    Returns:
    
    true if the storage element exists, false if it doesn't
    
    Throws:
    
    StorageException - if an error occurred while querying the storage
  - exists
```
boolean exists()
        throws StorageException
```
    Determine if the basic storage elements exist Basic storage elements include the 'object' storage (where all objects and their types are registered).
    
    Returns:
    
    true if basic storage elements exist
    
    Throws:
    
    StorageException - if an error occurred while querying the storage
  - size
```
int size(MMObjectBuilder builder)
  throws StorageException
```
    Return the number of objects of a builder in the storage
    
    Parameters:
    
    builder - the builder whose objects to count
    
    Returns:
    
    the number of objects the builder has
    
    Throws:
    
    StorageException - if the storage element for the builder does not exists
  - size
```
int size()
  throws StorageException
```
    Return the total number of objects in the storage
    
    Returns:
    
    the number of objects
    
    Throws:
    
    StorageException - if the basic storage elements do not exist
  - create
```
void create(CoreField field)
     throws StorageException
```
    Creates a field and adds it to the storage of this builder.
    
    Parameters:
    
    field - the CoreField of the field to add
    
    Throws:
    
    StorageException
  - change
```
void change(CoreField field)
     throws StorageException
```
    Changes a field to the storage of this builder.
    
    Parameters:
    
    field - the CoreField of the field to change
    
    Throws:
    
    StorageException
  - delete
```
void delete(CoreField field)
     throws StorageException
```
    Deletes a field from the storage of this builder.
    
    Parameters:
    
    field - the CoreField of the field to delete
    
    Throws:
    
    StorageException
  - isNull
```
boolean isNull(MMObjectNode node,
               CoreField field)
        throws StorageException
```
    Checks for null values for a field from the storage of this builder.
    
    Parameters:
    
    node - the node to check the value for
    
    field - the CoreField
    
    Returns:
    
    true when value is null in storage
    
    Throws:
    
    StorageException - if an error occurred during the get

Interface StorageManager<SMF extends StorageManagerFactory>

Method Summary

Method Detail

getVersion

init

beginTransaction

commit

rollback

createKey

getStringValue

getBinaryValue

getInputStreamValue

create

change

delete

setNodeType

getNode

getNodeType

create

create

change

delete

exists

exists

size

size

create

change

delete

isNull