Improve behavior of close in JDK versions where AutoCloseable is not available. In JDK 1.5 and 1.6, call ResultSet.close() or Closeable.close() if the underlying object is either of those types. In JDK 1.7 onwards, they are all AutoCloseable.
diff --git a/src/main/java/net/hydromatic/linq4j/Linq4j.java b/src/main/java/net/hydromatic/linq4j/Linq4j.java
index 28a1c6f..28963de 100644
--- a/src/main/java/net/hydromatic/linq4j/Linq4j.java
+++ b/src/main/java/net/hydromatic/linq4j/Linq4j.java
@@ -18,6 +18,9 @@
package net.hydromatic.linq4j;
import java.io.Closeable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.sql.ResultSet;
import java.util.*;
/**
@@ -26,6 +29,20 @@
public class Linq4j {
private static final Object DUMMY = new Object();
+ private static final Method AUTO_CLOSEABLE_CLOSE_METHOD =
+ getMethod("java.lang.AutoCloseable", "close");
+
+ private static Method getMethod(String className, String methodName,
+ Class... parameterTypes) {
+ try {
+ return Class.forName(className).getMethod(methodName, parameterTypes);
+ } catch (NoSuchMethodException e) {
+ return null;
+ } catch (ClassNotFoundException e) {
+ return null;
+ }
+ }
+
/**
* Query provider that simply executes a {@link Queryable} by calling its
* enumerator method; does not attempt optimization.
@@ -380,13 +397,39 @@
public void close() {
final Iterator<T> iterator = this.iterator;
this.iterator = null;
- if (iterator instanceof Closeable) {
- try {
- ((Closeable) iterator).close();
- } catch (RuntimeException e) {
- throw e;
- } catch (Exception e) {
- throw new RuntimeException(e);
+ if (AUTO_CLOSEABLE_CLOSE_METHOD != null) {
+ // JDK 1.7 or later
+ if (AUTO_CLOSEABLE_CLOSE_METHOD.getDeclaringClass()
+ .isInstance(iterator)) {
+ try {
+ AUTO_CLOSEABLE_CLOSE_METHOD.invoke(iterator);
+ } catch (IllegalAccessException e) {
+ throw new RuntimeException(e);
+ } catch (InvocationTargetException e) {
+ throw new RuntimeException(e.getCause());
+ }
+ }
+ } else {
+ // JDK 1.5 or 1.6. No AutoCloseable. Cover the two most common cases
+ // with a close().
+ if (iterator instanceof Closeable) {
+ try {
+ ((Closeable) iterator).close();
+ return;
+ } catch (RuntimeException e) {
+ throw e;
+ } catch (Exception e) {
+ throw new RuntimeException(e);
+ }
+ }
+ if (iterator instanceof ResultSet) {
+ try {
+ ((ResultSet) iterator).close();
+ } catch (RuntimeException e) {
+ throw e;
+ } catch (Exception e) {
+ throw new RuntimeException(e);
+ }
}
}
}
