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 4984b31e9c617a63b3a5bdf9a31f539064dea6c3
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Sat Jun 10 12:42:31 2023 +0200
Replace reflection by `ServiceLoader` uses in the `OptionalDependency`
class.
This is needed because reflection no longer works after module
encapsulation.
---
.../sis/internal/metadata/ReferencingServices.java | 17 ++++----
.../org.apache.sis.internal.util.MetadataServices | 1 +
...pache.sis.internal.metadata.ReferencingServices | 1 +
.../sis/internal/system/OptionalDependency.java | 50 ++++++----------------
.../apache/sis/internal/util/MetadataServices.java | 12 +++---
5 files changed, 30 insertions(+), 51 deletions(-)
diff --git
a/core/sis-metadata/src/main/java/org/apache/sis/internal/metadata/ReferencingServices.java
b/core/sis-metadata/src/main/java/org/apache/sis/internal/metadata/ReferencingServices.java
index 8e297de80f..7ab7d3e8a7 100644
---
a/core/sis-metadata/src/main/java/org/apache/sis/internal/metadata/ReferencingServices.java
+++
b/core/sis-metadata/src/main/java/org/apache/sis/internal/metadata/ReferencingServices.java
@@ -18,6 +18,7 @@ package org.apache.sis.internal.metadata;
import java.util.Locale;
import java.util.TimeZone;
+import java.util.ServiceLoader;
import java.text.Format;
import org.opengis.geometry.Envelope;
import org.opengis.geometry.DirectPosition;
@@ -37,11 +38,8 @@ import org.apache.sis.internal.system.Modules;
/**
* Provides access to services defined in the {@code "sis-referencing"} module.
- * This class searches for the {@link
org.apache.sis.internal.referencing.ServicesForMetadata}
- * implementation using Java reflection.
- *
- * <p>This class also opportunistically defines some methods and constants
related to
- * <cite>"referencing by coordinates"</cite> but needed by metadata.</p>
+ * This class also opportunistically defines some methods and constants related
+ * to <cite>"referencing by coordinates"</cite> but needed by metadata.
*
* @author Martin Desruisseaux (Geomatys)
* @version 1.4
@@ -62,6 +60,9 @@ public class ReferencingServices extends OptionalDependency {
/**
* The services, fetched when first needed.
+ * Guaranteed non-null after the search was done, even if the service
implementation was not found.
+ *
+ * @see #getInstance()
*/
private static volatile ReferencingServices instance;
@@ -82,7 +83,6 @@ public class ReferencingServices extends OptionalDependency {
@Override
protected final void classpathChanged() {
synchronized (ReferencingServices.class) {
- super.classpathChanged();
instance = null;
}
}
@@ -100,12 +100,11 @@ public class ReferencingServices extends
OptionalDependency {
c = instance;
if (c == null) {
/*
- * Double-checked locking: okay since Java 5 provided that
the 'instance' field is volatile.
+ * Double-checked locking: okay since Java 5 provided that
the `instance` field is volatile.
* In the particular case of this class, the intent is to
ensure that SystemListener.add(…)
* is invoked only once.
*/
- c = getInstance(ReferencingServices.class,
Modules.METADATA, "sis-referencing",
-
"org.apache.sis.internal.referencing.ServicesForMetadata");
+ c = getInstance(ReferencingServices.class,
ServiceLoader.load(ReferencingServices.class), "sis-referencing");
if (c == null) {
c = new ReferencingServices();
}
diff --git
a/core/sis-metadata/src/main/resources/META-INF/services/org.apache.sis.internal.util.MetadataServices
b/core/sis-metadata/src/main/resources/META-INF/services/org.apache.sis.internal.util.MetadataServices
new file mode 100644
index 0000000000..ebf1b0244f
--- /dev/null
+++
b/core/sis-metadata/src/main/resources/META-INF/services/org.apache.sis.internal.util.MetadataServices
@@ -0,0 +1 @@
+org.apache.sis.internal.metadata.ServicesForUtility
diff --git
a/core/sis-referencing/src/main/resources/META-INF/services/org.apache.sis.internal.metadata.ReferencingServices
b/core/sis-referencing/src/main/resources/META-INF/services/org.apache.sis.internal.metadata.ReferencingServices
new file mode 100644
index 0000000000..8398b4e88f
--- /dev/null
+++
b/core/sis-referencing/src/main/resources/META-INF/services/org.apache.sis.internal.metadata.ReferencingServices
@@ -0,0 +1 @@
+org.apache.sis.internal.referencing.ServicesForMetadata
diff --git
a/core/sis-utility/src/main/java/org/apache/sis/internal/system/OptionalDependency.java
b/core/sis-utility/src/main/java/org/apache/sis/internal/system/OptionalDependency.java
index bc7c9964ba..f60d74d809 100644
---
a/core/sis-utility/src/main/java/org/apache/sis/internal/system/OptionalDependency.java
+++
b/core/sis-utility/src/main/java/org/apache/sis/internal/system/OptionalDependency.java
@@ -16,6 +16,7 @@
*/
package org.apache.sis.internal.system;
+import java.util.ServiceLoader;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import org.apache.sis.util.logging.Logging;
@@ -29,7 +30,7 @@ import org.apache.sis.util.resources.Messages;
* services of the {@code "sis-referencing"} module if the latter is present
on the classpath.
*
* @author Martin Desruisseaux (Geomatys)
- * @version 0.6
+ * @version 1.4
* @since 0.6
*/
public abstract class OptionalDependency extends SystemListener {
@@ -52,51 +53,28 @@ public abstract class OptionalDependency extends
SystemListener {
SystemListener.add(this);
}
- /**
- * Invoked when the classpath is likely to have changed.
- * Subclasses must override like below:
- *
- * {@snippet lang="java" :
- * @Override
- * protected final void classpathChanged() {
- * synchronized (MyServices.class) {
- * super.classpathChanged();
- * instance = null;
- * }
- * }
- * }
- */
- @Override
- protected void classpathChanged() {
- SystemListener.remove(this);
- }
-
/**
* Returns the optional dependency, or {@code null} if not found.
* This is a helper method for implementation of {@code getInstance()}
static method in subclasses.
+ * The service loader needs to be created by the caller because of Java
module encapsulation rules.
*
- * @param <T> compile-time type of the {@code type} argument.
- * @param type the subclass type.
- * @param module same argument value than the one given to the
{@linkplain #OptionalDependency constructor}.
- * @param dependency same argument value than the one given to the
{@linkplain #OptionalDependency constructor}.
- * @param implementation the fully-qualified name of the class to
instantiate by reflection.
+ * @param <T> compile-time type of the {@code type} argument.
+ * @param type the service type, used only if a warning needs to
be logged.
+ * @param loader the service loader created in the module that needs
the service.
+ * @param dependency same argument value than the one given to the
{@linkplain #OptionalDependency constructor}.
* @return an instance of the {@code implementation} class, or {@code
null} if not found.
*/
protected static <T extends OptionalDependency> T getInstance(final
Class<T> type,
- final String module, final String dependency, final String
implementation)
+ final ServiceLoader<T> loader, final String
dependency)
{
- try {
- return type.cast(Class.forName(implementation).newInstance());
- } catch (ClassNotFoundException exception) {
- final LogRecord record =
Messages.getResources(null).getLogRecord(Level.CONFIG,
- Messages.Keys.OptionalModuleNotFound_1, dependency);
- record.setLoggerName(module);
+ final T first = loader.findFirst().orElse(null);
+ if (first == null) {
+ LogRecord record =
Messages.getResources(null).getLogRecord(Level.CONFIG,
+ Messages.Keys.OptionalModuleNotFound_1,
dependency);
+ record.setLoggerName(type.getModule().getName());
Logging.completeAndLog(null, type, "getInstance", record);
- return null;
- } catch (ReflectiveOperationException exception) {
- // Should never happen if we didn't broke our helper class.
- throw new AssertionError(exception);
}
+ return first;
}
/**
diff --git
a/core/sis-utility/src/main/java/org/apache/sis/internal/util/MetadataServices.java
b/core/sis-utility/src/main/java/org/apache/sis/internal/util/MetadataServices.java
index ff6a7f1f12..bbc43df887 100644
---
a/core/sis-utility/src/main/java/org/apache/sis/internal/util/MetadataServices.java
+++
b/core/sis-utility/src/main/java/org/apache/sis/internal/util/MetadataServices.java
@@ -19,6 +19,7 @@ package org.apache.sis.internal.util;
import java.text.Format;
import java.util.Locale;
import java.util.TimeZone;
+import java.util.ServiceLoader;
import java.util.MissingResourceException;
import java.util.function.Supplier;
import javax.sql.DataSource;
@@ -36,8 +37,6 @@ import org.opengis.util.ControlledVocabulary;
/**
* Provides access to services defined in the {@code "sis-metadata"} module.
- * This class searches for the {@link
org.apache.sis.internal.metadata.ServicesForUtility}
- * implementation using Java reflection.
*
* @author Martin Desruisseaux (Geomatys)
* @version 1.4
@@ -52,6 +51,9 @@ public class MetadataServices extends OptionalDependency {
/**
* The services, fetched when first needed.
+ * Guaranteed non-null after the search was done, even if the service
implementation was not found.
+ *
+ * @see #getInstance()
*/
private static volatile MetadataServices instance;
@@ -71,7 +73,6 @@ public class MetadataServices extends OptionalDependency {
@Override
protected final void classpathChanged() {
synchronized (MetadataServices.class) {
- super.classpathChanged();
instance = null;
}
}
@@ -89,12 +90,11 @@ public class MetadataServices extends OptionalDependency {
c = instance;
if (c == null) {
/*
- * Double-checked locking: okay since Java 5 provided that
the 'instance' field is volatile.
+ * Double-checked locking: okay since Java 5 provided that
the `instance` field is volatile.
* In the particular case of this class, the intent is to
ensure that SystemListener.add(…)
* is invoked only once.
*/
- c = getInstance(MetadataServices.class, Modules.UTILITIES,
"sis-metadata",
-
"org.apache.sis.internal.metadata.ServicesForUtility");
+ c = getInstance(MetadataServices.class,
ServiceLoader.load(MetadataServices.class), "sis-metadata");
if (c == null) {
c = new MetadataServices();
}
