[#11543] Remove unnecessary EnumerationFilter

agent-module/bootstraps/bootstrap-core/src/main/java/com/navercorp/pinpoint/bootstrap/context/Header.java

@@ -16,7 +16,7 @@
 
 package com.navercorp.pinpoint.bootstrap.context;
 
-import com.navercorp.pinpoint.common.util.DelegateEnumeration;
+import java.util.function.Predicate;
 
 /**
  * @author emeroad
@@ -54,9 +54,10 @@ public static boolean startWithPinpointHeader(final String name) {
         return name.regionMatches(true, 0, FILTER_PATTERN_PREFIX, 0, FILTER_PATTERN_PREFIX_LENGTH);
     }
 
-    public static DelegateEnumeration.Filter FILTER = new DelegateEnumeration.Filter() {
+    @SuppressWarnings("rawtypes")
+    public static Predicate FILTER = new Predicate() {
         @Override
-        public boolean filter(Object o) {
+        public boolean test(Object o) {
             if (o instanceof String) {
                 return startWithPinpointHeader((String) o);
             }

commons/src/main/java/com/navercorp/pinpoint/common/util/DelegateEnumeration.java

@@ -17,6 +17,7 @@
 package com.navercorp.pinpoint.common.util;
 
 import java.util.Enumeration;
+import java.util.function.Predicate;
 
 /**
  * @author emeroad
@@ -25,26 +26,17 @@ public class DelegateEnumeration<E> implements Enumeration<E> {
     private static final Object NULL_OBJECT = new Object();
 
     private final Enumeration<E> delegate;
-    private final Filter<E> filter;
+    private final Predicate<E> filter;
 
     private boolean hasMoreElements;
     private E nextElement;
     private Exception nextException;
 
-
-    private static final Filter SKIP_FILTER = new Filter() {
-        @Override
-        public boolean filter(Object o) {
-            return false;
-        }
-    };
-
-    @SuppressWarnings("unchecked")
     public DelegateEnumeration(Enumeration<E> delegate) {
-        this(delegate, SKIP_FILTER);
+        this(delegate, Predicates.isFalse());
     }
 
-    public DelegateEnumeration(Enumeration<E> delegate, Filter<E> filter) {
+    public DelegateEnumeration(Enumeration<E> delegate, Predicate<E> filter) {
         this.delegate = delegate;
         this.filter = filter;
     }
@@ -109,7 +101,7 @@ private void next(final boolean hasMoreElementMethod) {
                 break;
             }
 
-            if (filter.filter(nextElement)) {
+            if (filter.test(nextElement)) {
                 continue;
             }
 
@@ -130,7 +122,4 @@ Exception _getNextException() {
         return nextException;
     }
 
-    public interface Filter<E> {
-        boolean filter(E e);
-    }
 }

commons/src/main/java/com/navercorp/pinpoint/common/util/EmptyEnumeration.java

@@ -22,6 +22,7 @@
  * @author emeroad
  */
 public class EmptyEnumeration<E> implements Enumeration<E> {
+    @SuppressWarnings("rawtypes")
     private static final NextElementAction NULL_NEXT_ELEMENT_ACTION = new NullNextElementAction();
 
     private final NextElementAction<E> nextElementAction;

commons/src/main/java/com/navercorp/pinpoint/common/util/Predicates.java

@@ -0,0 +1,46 @@
+package com.navercorp.pinpoint.common.util;
+
+import java.util.function.Predicate;
+
+
+public final class Predicates {
+    private Predicates() {
+    }
+
+    @SuppressWarnings("rawtypes")
+    private static final Predicate IS_TRUE = new Predicate() {
+        @Override
+        public boolean test(Object o) {
+            return true;
+        }
+
+        @Override
+        public String toString() {
+            return "Predicates.isTrue()";
+        }
+    };
+
+    @SuppressWarnings("rawtypes")
+    private static final Predicate IS_FALSE = new Predicate() {
+        @Override
+        public boolean test(Object o) {
+            return false;
+        }
+
+        @Override
+        public String toString() {
+            return "Predicates.isFalse()";
+        }
+    };
+
+    @SuppressWarnings("unchecked")
+    public static <T> Predicate<T> isTrue() {
+        return (Predicate<T>) IS_TRUE;
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <T> Predicate<T> isFalse() {
+        return IS_FALSE;
+    }
+
+}

commons/src/test/java/com/navercorp/pinpoint/common/util/DelegateEnumerationTest.java

@@ -24,6 +24,7 @@
 import java.util.Hashtable;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.function.Predicate;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
@@ -104,13 +105,10 @@ public void testSkip() {
         List<String> valueList = new ArrayList<>(hashTable.values());
 
         Enumeration<String> enumeration = hashTable.elements();
-        DelegateEnumeration<String> delegateEnumeration = new DelegateEnumeration<>(enumeration, new DelegateEnumeration.Filter<String>() {
+        DelegateEnumeration<String> delegateEnumeration = new DelegateEnumeration<>(enumeration, new Predicate<String>() {
             @Override
-            public boolean filter(String s) {
-                if ("bb".equals(s)) {
-                    return true;
-                }
-                return false;
+            public boolean test(String s) {
+                return "bb".equals(s);
             }
         });
 

commons/src/test/java/com/navercorp/pinpoint/common/util/PredicatesTest.java

@@ -0,0 +1,27 @@
+package com.navercorp.pinpoint.common.util;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.function.Predicate;
+
+
+class PredicatesTest {
+
+    @Test
+    void isTrue() {
+        Predicate<String> predicate = Predicates.isTrue();
+        Assertions.assertTrue(predicate.test("test"));
+
+        Assertions.assertSame(predicate, Predicates.isTrue());
+    }
+
+    @Test
+    void isFalse() {
+        Predicate<String> predicate = Predicates.isFalse();
+        Assertions.assertFalse(predicate.test("test"));
+
+        Assertions.assertSame(predicate, Predicates.isFalse());
+    }
+
+}