tgz: Implemented ColumnSnapshotGenerator to handle numeric boolean de…

…fault values in snapshots (#191)

* tgz: Implemented ColumnSnapshotGenerator to handle numeric boolean default values in snapshots

* ColumnSnapshotGeneratorHana, improved priority evaluation, restricting to HanaDatabase

src/main/java/liquibase/ext/hana/snapshot/ColumnSnapshotGeneratorHana.java

@@ -0,0 +1,47 @@
+package liquibase.ext.hana.snapshot;
+
+import liquibase.database.Database;
+import liquibase.ext.hana.HanaDatabase;
+import liquibase.snapshot.CachedRow;
+import liquibase.snapshot.SnapshotGenerator;
+import liquibase.snapshot.jvm.ColumnSnapshotGenerator;
+import liquibase.statement.DatabaseFunction;
+import liquibase.structure.DatabaseObject;
+import liquibase.structure.core.Column;
+
+public class ColumnSnapshotGeneratorHana extends ColumnSnapshotGenerator {
+
+    @Override
+    public int getPriority(Class<? extends DatabaseObject> objectType, Database database) {
+        if (!(database instanceof HanaDatabase)) {
+            return PRIORITY_NONE;
+        }
+        int priority = super.getPriority(objectType, database);
+        if (priority > PRIORITY_NONE) {
+            priority += PRIORITY_DATABASE;
+        }
+        return priority;
+    }
+
+    @Override
+    public Class<? extends SnapshotGenerator>[] replaces() {
+        return new Class[]{ColumnSnapshotGenerator.class};
+    }
+
+    @Override
+    protected Object readDefaultValue(CachedRow columnMetadataResultSet, Column columnInfo, Database database) {
+        Object defaultValue = super.readDefaultValue(columnMetadataResultSet, columnInfo, database);
+        String typeName = columnMetadataResultSet.getString("TYPE_NAME").toUpperCase();
+        if ("BOOLEAN".equals(typeName)) {
+            if (defaultValue instanceof DatabaseFunction) {
+                String defaultAsString = ((DatabaseFunction) defaultValue).getValue();
+                if ("0".equals(defaultAsString)) {
+                    return "FALSE";
+                } else if ("1".equals(defaultAsString)) {
+                    return "TRUE";
+                }
+            }
+        }
+        return defaultValue;
+    }
+}

src/main/resources/META-INF/services/liquibase.snapshot.SnapshotGenerator

@@ -1,2 +1,3 @@
 liquibase.ext.hana.snapshot.SequenceSnapshotGeneratorHana
 liquibase.ext.hana.snapshot.UniqueConstraintSnapshotGeneratorHana
+liquibase.ext.hana.snapshot.ColumnSnapshotGeneratorHana