liquibase.snapshot

Interface SnapshotGenerator

All Known Implementing Classes:

CatalogSnapshotGenerator, ColumnSnapshotGenerator, ColumnSnapshotGeneratorH2, ColumnSnapshotGeneratorInformix, ColumnSnapshotGeneratorOracle, ColumnSnapshotGeneratorPostgres, DataSnapshotGenerator, ForeignKeySnapshotGenerator, IndexSnapshotGenerator, JdbcSnapshotGenerator, PrimaryKeySnapshotGenerator, SchemaSnapshotGenerator, SequenceSnapshotGenerator, TableSnapshotGenerator, UniqueConstraintSnapshotGenerator, ViewSnapshotGenerator

public interface SnapshotGenerator

Field Summary

Fields

Modifier and Type	Field and Description
static int	PRIORITY_ADDITIONAL
static int	PRIORITY_DATABASE
static int	PRIORITY_DEFAULT
static int	PRIORITY_NONE

Method Summary

Modifier and Type	Method and Description
Class<? extends DatabaseObject>[]	addsTo() When snapshotting a certain object type (e.g.
int	getPriority(Class<? extends DatabaseObject> objectType, Database database) Inquire if this SnapshotGenerator is capable of snapshotting objects of type objectType (e.g.
Class<? extends SnapshotGenerator>[]	replaces() Returns classes (and superclasses) that this SnapshotGenerator replaces.
<T extends DatabaseObject> T	snapshot(T example, DatabaseSnapshot snapshot, SnapshotGeneratorChain chain) Commands the SnapshotGenerator to create a snapshot (a representation of a database object in Java object form) of a specific database object.

Field Detail

PRIORITY_NONE

static final int PRIORITY_NONE

See Also:

Constant Field Values

PRIORITY_DEFAULT

static final int PRIORITY_DEFAULT

See Also:

Constant Field Values

PRIORITY_DATABASE

static final int PRIORITY_DATABASE

See Also:

Constant Field Values

PRIORITY_ADDITIONAL

static final int PRIORITY_ADDITIONAL

See Also:

Constant Field Values

Method Detail

getPriority

int getPriority(Class<? extends DatabaseObject> objectType,
                Database database)

Inquire if this SnapshotGenerator is capable of snapshotting objects of type objectType (e.g. Table, Index, View etc.) in the DBMS database (e.g. Oracle, Postgres, HyperSQL etc.) A return priority of > 0 will be interpreted as capable. The highest priority for an objectType-database combination wins.

Parameters:

objectType - The object type we are asked to snapshot

database - The DBMS for which the snapshotting should be done

Returns:

An integer of PRIORITY_... constants indicating our capability and willingness to snapshot

snapshot

<T extends DatabaseObject> T snapshot(T example,
                                      DatabaseSnapshot snapshot,
                                      SnapshotGeneratorChain chain)
                               throws DatabaseException,
                                      InvalidExampleException

Commands the SnapshotGenerator to create a snapshot (a representation of a database object in Java object form) of a specific database object.

Type Parameters:

T - The Java object type in which we are to return the snapshot result

Parameters:

example - The object we should try to snapshot

snapshot - The Snapshot object representating the result of the snapshot operations so far

chain - A list of other SnapshotGenerators that might be asked to try the same

Returns:

An object of type T if our snapshot attempt is successful

Throws:

DatabaseException - If an operation on the database fails

InvalidExampleException - If, for some reason, we cannot work on the example object (ambiguous naming etc.)

addsTo

Class<? extends DatabaseObject>[] addsTo()

When snapshotting a certain object type (e.g. a table), different types of objects might be discovered in the process. (TODO: Which ones? Needs a more precise description.)

Returns:

an array of classes that this SnapshotGenerator might return upon snapshotting a given DatabaseObject type.

replaces

Class<? extends SnapshotGenerator>[] replaces()

Returns classes (and superclasses) that this SnapshotGenerator replaces. Return null or empty array to not affect the SnapshotGeneratorChain.