@LcdService(service=ILcdModelDecoder.class, priority=20000) public class TLcdPostGISModelDecoder extends Object implements ILcdModelDecoder
| File | Required | Entry point | Description |
|---|---|---|---|
| *.pgs | x | Java properties file containing all the necessary properties to access the spatial data |
Alternatively, a Properties object can be constructed
programmatically and passed to the model decoder.
The common properties needed to establish a connection are:
driver (default = org.postgresql.Driver):
the JDBC driver that will be used to connect to the database.
url: the database URL.
user: the database user name.
password: the user's password.
The properties that identify the tables, columns, rows, etc. within the database are:
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.
dimensions (default = 2):
specifies the coordinate dimension of the geometries stored in the table.
When working with 3D geometry this should be set to 3. This parameter is only
used when a new table needs to be created, otherwise the dimensions are read from
the database.
If a schema name, table name, or spatial column name is surrounded by double quotes (") then the quotes are stripped and the remaining string is passed unmodified to PostgreSQL. If a name is not quoted, then it is converted to lower case before being passed on to the database. See the PostgreSQL documentation for a more detailed explanation. A schema name may be quoted separately from the actual table name.
ILcd2DBoundsIndexedModel.TLcdPostGISModelDescriptor.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 PostGIS provides:
FROMWKB GEOMETRY | TOILcdShape |
|---|---|
POINT | ILcdShapeList with an ILcd2DEditablePoint or ILcd3DEditablePoint object |
LINESTRING | ILcdShapeList with an ILcd2DEditablePolyline or ILcd3DEditablePolyline object |
POLYGON | ILcdShapeList with an ILcdComplexPolygon object |
MULTIPOINT | ILcdShapeList with an ILcd2DEditablePolypoint or ILcd3DEditablePolypoint object |
MULTILINESTRING | ILcdShapeList with ILcd2DEditablePolyline or ILcd3DEditablePolyline objects |
MULTIPOLYGON | ILcdShapeList with ILcdComplexPolygon objects |
GEOMETRYCOLLECTION | ILcdShapeList with objects from this table (also recursive) |
ILcdFeatured interface and the
ILcdDataObject interface, providing access to their features.ILcdShape that provides access to the M coordinate value.
For example, an POINTZM will be decoded as an TLcdLonLatHeightMPoint
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 TLcdPostGISModelDecoder(true);
ILcdModel model = decoder.decode("countries.pgs");
The file countries.pgs could for instance contain the following
properties:
# The basic database connection properties.
driver = org.postgresql.Driver
url = jdbc:postgresql://server:5432/database
user = user
password = password
# The data of interest.
table = MY_SCHEMA.COUNTRIES
spatialColumn = GEOM
# The feature columns to be decoded.
featureNames.0 = ID
# 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 = POPULATION
#selectionFilter = COUNTRIES.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.
# Only advisable when using a connection pooling database driver.
#alwaysCloseConnection = false
alwaysCloseConnection (default = false): an
optional boolean to specify that the database connection should be closed
after each query. Setting this flag can be useful for database drivers
that pool connections, so the connections are reused instead of really
being closed.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.| Constructor and Description |
|---|
TLcdPostGISModelDecoder()
Creates a new, read-write PostgreSQL PostGIS model decoder.
|
TLcdPostGISModelDecoder(boolean aReadOnly)
Creates a new PostgreSQL PostGIS 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 given 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() |
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 TLcdPostGISModelDecoder()
public TLcdPostGISModelDecoder(boolean aReadOnly)
aReadOnly - specifies the type of models the decoder should construct.setReadOnly(boolean)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()
setReadOnly()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
decode in interface ILcdModelDecoderaSourceName - the data source to be decoded; typically a file name or a URL.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
IOException