PR #9 'ApplyLimitOffset' from mjohns-databricks/databricks-geotools-p…

…lugin#9
a0x8o · Mar 6, 2023 · 5a29d84 · 5a29d84
1 parent 98911bc
commit 5a29d84
Show file tree

Hide file tree

Showing 3 changed files with 37 additions and 6 deletions.
diff --git a/geotools-plugin/README.md b/geotools-plugin/README.md
@@ -31,8 +31,8 @@ Additionally, for data engineering, you may want to install the following useful
 - sedona (PyPI)
 - shapely (PyPI)
 - apache-sedona\[spark\] (PyPI)
-- h3 (PyPI) (provided by Mosaic, JAR by DBR)
-- geospark (PyPI) (provided by DBR)
+- h3 (PyPI) (Optional)
+- geospark (PyPI) (Optional)
 - geopandas (PyPI) (Optional)
 
 For instructions on how to install libraries on your cluster, see the [documentation here](https://docs.databricks.com/libraries/index.html).

diff --git a/geotools-plugin/pom.xml b/geotools-plugin/pom.xml
@@ -5,10 +5,10 @@
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>com.databricks.geotools</groupId>
-  <artifactId>databricks-gt_0.0.2</artifactId>
-  <version>0.0.2-SNAPSHOT</version>
+  <artifactId>databricks-gt_0.0.5</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
 
-  <name>databricks-gt_0.0.2</name>
+  <name>databricks-gt_0.0.5</name>
   <url>http://www.databricks.com</url>
 
   <properties>

diff --git a/geotools-plugin/src/main/java/com/databricks/geotools/DatabricksSQLDialect.java b/geotools-plugin/src/main/java/com/databricks/geotools/DatabricksSQLDialect.java
@@ -34,11 +34,16 @@ public void setMetadataTableName(String tableName) {
 
 	public DatabricksSQLDialect(JDBCDataStore dataStore, Integer refreshPeriod) {
 		super(dataStore);
+
+		LOGGER.fine("Creating DatabricksSQLDialect");
+
 		this.wktReader = new WKTReader(new GeometryFactory(new PrecisionModel(PrecisionModel.FLOATING), 4326));
     	this.wkbReader = ThreadLocal.withInitial(() -> new WKBReader(new GeometryFactory(new PrecisionModel(PrecisionModel.FLOATING), 4326)));
     	this.metadataTableName = GT_PK_METADATA;
     	this.refreshPeriod = refreshPeriod;
     	this.layersList = new LayersList();
+
+		LOGGER.fine("DatabricksSQLDialect creation complete");
 	}
 
 	@Override
@@ -48,9 +53,35 @@ public boolean includeTable(String schemaName, String tableName, Connection cx)
 		if (mtn == null) mtn = GT_PK_METADATA;
 
 		return layersList.includeTable(schemaName, tableName, mtn, dataStore, cx, refreshPeriod);
-
     }
 
 	public LayersList getLayersList() {return layersList;}
+
+	@Override
+    public boolean isLimitOffsetSupported() {
+		LOGGER.fine("In DatabricksSQLDialect.isLimitOffsetSupported");
+
+		return true;
+    }
+
+    @Override
+    public void applyLimitOffset(StringBuffer sql, int limit, int offset) {
+		LOGGER.fine("In DatabricksSQLDialect.applyLimitOffset...");
+		LOGGER.fine("Value of of sql BEFORE limit is applied: " + sql);
+		LOGGER.fine("Value of of limit: " + limit);
+		LOGGER.fine("Value of of offset: " + offset);
+
+        if (limit >= 0 && limit < Integer.MAX_VALUE) {
+            sql.append(" LIMIT " + limit);
+            if (offset > 0) {
+                sql.append(" OFFSET " + offset);
+            }
+        } else if (offset > 0) {
+            sql.append(" LIMIT " + Integer.MAX_VALUE);
+            sql.append(" OFFSET " + offset);
+        }
+		LOGGER.fine("Value of of sql AFTER limit is applied: " + sql);
+
+    }
 
 }