@LcdService(priority=20000) public class TLcdMSSQLModelDecoder extends Object implements ILcdModelDecoder
| File | Required | Entry point | Description |
|---|---|---|---|
| *.mss | x | Java properties file containing all the necessary properties to access the spatial data |
Properties object can be constructed
programmatically and passed to the model decoder.
The common properties needed to establish a connection are:
driver (default = com.microsoft.sqlserver.jdbc.SQLServerDriver):
the JDBC driver that will be used to connect to the database.
url: the database URL, absolute or relative to the location of the properties
file.
table: the name of the table containing the geometries. The
table name may be qualified by prepending the database schema. It may
be followed by one or more spaces and an alias, which can be used instead
of the original name to disambiguate columns in the other properties.
spatialColumn: the column containing the geometries.
spatialQueryColumn: an optional column containing the
geometries that should be used in spatial queries. By default, this
column is equal to the spatialColumn. It should not be
changed for most typical applications.
featureNames.0, ...: the column names that should be retrieved
as object features in the model. For read-only models, more complex SQL
expressions, or columns from selection tables (see below) are accepted too.
featureDisplayNames.0, ...: optional display names
corresponding to the feature names.
primaryFeatureIndex (default = 0): the index of the feature
that serves as a primary key.
primaryFeatureAutoGenerated (default = false):
specifies whether the database automatically generates the primary key
whenever a geometry is inserted into the spatial table. The primary
feature on the java side will then be updated with this generated value.
selectionTables (default = null): an optional
comma-separated list of tables required to constrain the geometries of the
model. These tables will be added after the main table in the FROM parts
of SELECT queries. A name may be followed by one or more spaces and an
alias, which can be used instead of the original name to disambiguate
columns in the other properties.
selectionFilter (default = null): an optional
SQL select query to constrain the geometries of the model. This query
will be added after the spatial query in the WHERE parts of SELECT
queries.
TLcdDatabaseModel
or TLcdDatabaseReadOnlyModel, depending on whether this
decoder creates
read-only models or not.ILcd2DBoundsIndexedModel.TLcdMSSQLModelDescriptor.sourceName (default = the source name that is passed to the
model decoder): the source name of the model descriptor.
typeName (default = the display name of the model decoder):
the type name of the model descriptor. The type name is also used when
composing the name of the data model.
displayName (default = the spatial table name): the display
name of the model descriptor. The display name is also used when
composing the name of the data model and the name of the data type.
setDefaultModelReference(com.luciad.model.ILcdModelReference)).
ILcdShape objects,
decoded from the Well-Known Binary representation that Microsoft SQL provides:
FROMWKB GEOMETRY | TOILcdShape |
|---|---|
POINT | ILcdShapeList
with an ILcd2DEditablePoint object |
LINESTRING | ILcdShapeList
with an ILcd2DEditablePolyline object |
POLYGON | ILcdShapeList
with an ILcdComplexPolygon object |
MULTIPOINT | ILcdShapeList
with an ILcd2DEditablePolypoint object |
MULTILINESTRING | ILcdShapeList
with ILcd2DEditablePolyline objects |
MULTIPOLYGON | ILcdShapeList
with ILcdComplexPolygon objects |
GEOMETRYCOLLECTION | ILcdShapeList
with objects from this table (also recursive) |
ILcdDataObject interface,
providing access to their features.ILcdShape that provides access to the M coordinate value.
For example, an POINT will be decoded as an TLcdLonLatMPoint
TLcdLonLatHeightMPoint, TLcdXYMPoint
or TLcdXYZMPoint that has a TLcdXYZMPoint.getM() method to access the M coordinate value.readOnly can be set to specify
whether the model will be used as a read-only model.
ILcdModelDecoder decoder = new TLcdMSSQLModelDecoder(true);
ILcdModel model = decoder.decode("world.mss");
world.mss could for instance contain the following
properties:
# The basic database connection properties.
driver = com.microsoft.sqlserver.jdbc.SQLServerDriver
url = jdbc:sqlserver://server:1433
user = user
password = password
# The data of interest.
table = world
spatialColumn = GEOM
# The feature columns to be decoded.
featureNames.0 = ID
featureNames.1 = COUNTRY
featureNames.2 = CAPITAL
featureNames.3 = POP_1994
# The index of the feature that can be used as primary key.
primaryFeatureIndex = 0
# Optional extra tables and SQL condition to restrict the database elements.
# Note that the above feature names also have to be prefixed with the table
# name if the column names are ambiguous, like the ID column below.
#selectionTables = POP_1994
#selectionFilter = world.ID = POPULATION.ID AND POPULATION.VALUE > 1e7
# Optional maximum cache size (expressed as number of objects, default is 100).
maxCacheSize = 500
# Optionally close the database connection after each query.
#alwaysCloseConnection = false
alwaysCloseConnection (default = false): an
optional boolean to specify that the database connection should be closed
after each query.maxCacheSize (default = 100, or the value set on the
decoder): the maximum number of objects in the cache. Using a cache will
improve performance if transferring and decoding geometries and their
features is relatively expensive compared to performing the original
SQL queries. The current implementation of the decoder will then perform
queries in two passes, first retrieving the relevant primary keys and
then retrieving and decoding the actual geometries and features that
are not in the cache. On the other hand, setting the cache size to 0 may
be better if performing SQL queries is relatively expensive. The current
implementation of the decoder will then perform queries in a single
pass, retrieving and decoding the relevant geometries every time.| Modifier and Type | Field and Description |
|---|---|
static String |
DISPLAY_NAME |
| Constructor and Description |
|---|
TLcdMSSQLModelDecoder()
Creates a new, read-write Microsoft SQL model decoder.
|
TLcdMSSQLModelDecoder(boolean aReadOnly)
Creates a new Microsoft SQL model decoder.
|
| Modifier and Type | Method and Description |
|---|---|
boolean |
canDecodeSource(String aSourceAsString)
Checks whether this model decoder can decode the specified data source.
|
ILcdModel |
decode(Properties aProperties)
Decodes a new database model based on the properties.
|
ILcdModel |
decode(String aSourceName)
Decodes a new database model based on the properties specified in the given
file.
|
int |
getDefaultMaxCacheSize()
Return the default maximum size of the cache, expressed in number of
elements (rows|geometries).
|
ILcdModelReference |
getDefaultModelReference()
Returns the default model reference to be assigned to decoded models.
|
String |
getDisplayName()
Returns a short, displayable name for the format that is decoded by this
ILcdModelDecoder. |
boolean |
getReadOnly()
Indicates what kind of models will be created by this decoder.
|
void |
setDefaultMaxCacheSize(int aDefaultMaxCacheSize)
Sets the default maximum size of the cache.
|
void |
setDefaultModelReference(ILcdModelReference aDefaultModelReference)
Sets the default model reference to be assigned to decoded models if no model reference can be
created based on information from the database.
|
void |
setReadOnly(boolean aReadOnly)
Specifies whether the decoded models should be read-only or not.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitcanDecodeSource, decodeModelMetadata, decodeModelMetadata, decodeSource, discoverDataSourcespublic static final String DISPLAY_NAME
public TLcdMSSQLModelDecoder(boolean aReadOnly)
aReadOnly - specifies the type of models the decoder should construct, see setReadOnly(boolean).public TLcdMSSQLModelDecoder()
public void setDefaultModelReference(ILcdModelReference aDefaultModelReference)
aDefaultModelReference - the default model reference.getDefaultModelReference()public ILcdModelReference getDefaultModelReference()
setDefaultModelReference(com.luciad.model.ILcdModelReference)public void setDefaultMaxCacheSize(int aDefaultMaxCacheSize)
maxCacheSize property in the properties file.aDefaultMaxCacheSize - the default maximum number of objects in the cache.public int getDefaultMaxCacheSize()
public void setReadOnly(boolean aReadOnly)
aReadOnly - specifies the type of models the decoder should construct.
If true, the decoder will create
TLcdDatabaseReadOnlyModel objects. If
false, the decoder will create
TLcdDatabaseModel
objects.public boolean getReadOnly()
true if the decoded models should be read-only, false otherwise.setReadOnly(boolean)public String getDisplayName()
ILcdModelDecoderILcdModelDecoder.getDisplayName in interface ILcdModelDecoderILcdModelDecoder.public boolean canDecodeSource(String aSourceAsString)
ILcdModelDecodertrue for a source name while decode throws an exception for that same source name.
For performance reasons, we strongly recommend that this will only be a simple test. For example: check the file extension of a file, but not that the file exists or contains expected content.
canDecodeSource in interface ILcdModelDecoderaSourceAsString - the data source to be verified; typically a file name or a URL.true if this decoder can likely decode the data specified by the source name, false
otherwise.ILcdModelDecoder.decode(String),
ILcdModelDecoder.decodeModelMetadata(String)public ILcdModel decode(String aSourceName) throws IOException
TLcdMSSQLModelDecoder for more information about the
properties.decode in interface ILcdModelDecoderaSourceName - The filename of the properties file.null is allowed, implementors are advised to throw an error instead.IOException - for any exceptions caused by IO problems or invalid data. Since decoding invalid data almost
always results in RunTimeExceptions (NullPointerException, IndexOutOfBoundsException,
IllegalArgumentException, ...) on unexpected places, implementations are advised to catch
RuntimeExceptions in their decode() method, and wrap them into an IOException, as illustrated
in the code snippet below.
public ILcdModel decode( String aSourceName ) throws IOException {
try (InputStream input = fInputStreamFactory.createInputStream(aSourceName)) {
// Perform decoding ...
} catch (RuntimeException e) {
throw new IOException(e);
}
}
InterruptedIOException - When the thread on which this method is called is interrupted: it is recommended to stop the decoding
and throw an InterruptedIOException.
This same exception can also be used if the decoder shows UI to the user, and the user cancels the decoding
through the UI.ILcdModelDecoder.canDecodeSource(String)public ILcdModel decode(Properties aProperties) throws IOException
TLcdMSSQLModelDecoder for more information about the
properties.aProperties - The properties that contain the database connection details.IOException