[sis] 02/02: Allow to fetch statistics in last resort if min/max are not specified in a netCDF file. This is disabled by default, because this operation is potentially costly.

[desruisseaux]

This is an automated email from the ASF dual-hosted git repository.

desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git

commit ac6a4fdb0219c1ecceba890a50e81e4caea8161c
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Tue Aug 2 16:28:06 2022 +0200

    Allow to fetch statistics in last resort if min/max are not specified in a 
netCDF file.
    This is disabled by default, because this operation is potentially costly.
---
 .../main/java/org/apache/sis/internal/netcdf/Variable.java  | 10 +++++++++-
 .../org/apache/sis/internal/storage/StoreUtilities.java     | 13 ++++++++++++-
 .../java/org/apache/sis/internal/storage/package-info.java  |  2 +-
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git 
a/storage/sis-netcdf/src/main/java/org/apache/sis/internal/netcdf/Variable.java 
b/storage/sis-netcdf/src/main/java/org/apache/sis/internal/netcdf/Variable.java
index 6bbb896069..4305b22bfa 100644
--- 
a/storage/sis-netcdf/src/main/java/org/apache/sis/internal/netcdf/Variable.java
+++ 
b/storage/sis-netcdf/src/main/java/org/apache/sis/internal/netcdf/Variable.java
@@ -48,13 +48,15 @@ import org.apache.sis.util.resources.Errors;
 import ucar.nc2.constants.CDM;                      // We use only String 
constants.
 import ucar.nc2.constants.CF;
 
+import static 
org.apache.sis.internal.storage.StoreUtilities.ALLOW_LAST_RESORT_STATISTICS;
+
 
 /**
  * A netCDF variable created by {@link Decoder}.
  *
  * @author  Martin Desruisseaux (Geomatys)
  * @author  Johann Sorel (Geomatys)
- * @version 1.1
+ * @version 1.3
  * @since   0.3
  * @module
  */
@@ -851,6 +853,12 @@ public abstract class Variable extends Node {
         NumberRange<?> range = decoder.convention().validRange(this);
         if (range == null) {
             range = getRangeFallback();
+            if (ALLOW_LAST_RESORT_STATISTICS && range == null) try {
+                range = read().range();
+            } catch (DataStoreException | IOException e) {
+                // It should be a fatal error, but maybe the user wants only 
metadata.
+                error(Variable.class, "getValidRange", e, 
Errors.Keys.CanNotRead_1, getName());
+            }
         }
         return range;
     }
diff --git 
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/StoreUtilities.java
 
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/StoreUtilities.java
index cd8fd65d9a..eaeb355bab 100644
--- 
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/StoreUtilities.java
+++ 
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/StoreUtilities.java
@@ -62,11 +62,22 @@ import org.opengis.feature.Feature;
  * Some methods may also move in public API if we feel confident enough.
  *
  * @author  Martin Desruisseaux (Geomatys)
- * @version 1.2
+ * @version 1.3
  * @since   1.0
  * @module
  */
 public final class StoreUtilities extends Static {
+    /**
+     * Whether to allow computation of statistics when no minimum/maximum 
values can be determined.
+     * This is a costly operation because it requires loading all data, so any 
code enabled by this
+     * flag should be executed in last resort only.
+     *
+     * <p>This flag can be set to {@code true} for exploring data that we can 
not visualize otherwise.
+     * But it should generally stay to {@code false}, because otherwise 
browsing resource metadata can
+     * become as costly (slow and high memory usage) as visualizing the full 
raster.</p>
+     */
+    public static final boolean ALLOW_LAST_RESORT_STATISTICS = false;
+
     /**
      * Logger for the {@value Modules#STORAGE} module. This is used when no 
more specific logger is available,
      * or if the more specific logger is not appropriate (e.g. because the log 
message come from base class).
diff --git 
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/package-info.java
 
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/package-info.java
index d07eeacb65..a110dc7d1f 100644
--- 
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/package-info.java
+++ 
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/package-info.java
@@ -25,7 +25,7 @@
  *
  * @author  Martin Desruisseaux (Geomatys)
  * @author  Johann Sorel (Geomatys)
- * @version 1.2
+ * @version 1.3
  * @since   0.4
  * @module
  */