Refined caching of AntPathStringMatcher per pattern

Introduced a "setCachePatterns(boolean)" method for explicit configuration, a default turnoff threshold at 65536 entries (at which point we're deciding that caching isn't worthwhile because patterns are unlikely to be reoccurring often enough), and an "AntPathStringMatcher getStringMatcher(String pattern)" template method.

Issue: SPR-10803

spring-core/src/test/java/org/springframework/util/AntPathMatcherTests.java

@@ -23,10 +23,11 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-import static org.junit.Assert.*;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.*;
+
 /**
  * @author Alef Arendsen
  * @author Seth Ladd
@@ -382,9 +383,10 @@ public class AntPathMatcherTests {
 		try {
 			pathMatcher.extractUriTemplateVariables("/web/{id:foo(bar)?}", "/web/foobar");
 			fail("Expected exception");
-		} catch (IllegalArgumentException e) {
+		}
+		catch (IllegalArgumentException ex) {
 			assertTrue("Expected helpful message on the use of capturing groups",
-					e.getMessage().contains("The number of capturing groups in the pattern"));
+					ex.getMessage().contains("The number of capturing groups in the pattern"));
 		}
 	}
 
@@ -560,4 +562,36 @@ public class AntPathMatcherTests {
 		assertTrue(pathMatcher.match("/group/{groupName}/members", "/group/  sales/members"));
 	}
 
+	@Test
+	public void testDefaultCacheSetting() {
+		match();
+		assertTrue(pathMatcher.stringMatcherCache.size() > 20);
+
+		for (int i = 0; i < 65536; i++) {
+			pathMatcher.match("test" + i, "test");
+		}
+		// Cache turned off because it went beyond the threshold
+		assertTrue(pathMatcher.stringMatcherCache.isEmpty());
+	}
+
+	@Test
+	public void testCacheSetToTrue() {
+		pathMatcher.setCachePatterns(true);
+		match();
+		assertTrue(pathMatcher.stringMatcherCache.size() > 20);
+
+		for (int i = 0; i < 65536; i++) {
+			pathMatcher.match("test" + i, "test");
+		}
+		// Cache keeps being alive due to the explicit cache setting
+		assertTrue(pathMatcher.stringMatcherCache.size() > 65536);
+	}
+
+	@Test
+	public void testCacheSetToFalse() {
+		pathMatcher.setCachePatterns(false);
+		match();
+		assertTrue(pathMatcher.stringMatcherCache.isEmpty());
+	}
+
 }