support min function. (#4072)

* support min function.

* fix logical bug and update test case.

* the same here.

oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/metrics/MinDoubleMetrics.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.server.core.analysis.metrics;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.Entrance;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.MetricsFunction;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.SourceFrom;
+import org.apache.skywalking.oap.server.core.storage.annotation.Column;
+
+/**
+ * @author jian.tan
+ */
+
+@MetricsFunction(functionName = "minDouble")
+public abstract class MinDoubleMetrics extends Metrics implements DoubleValueHolder {
+
+    protected static final String VALUE = "value";
+
+    @Getter @Setter @Column(columnName = VALUE, isValue = true) private double value = Double.MAX_VALUE;
+
+    @Entrance
+    public final void combine(@SourceFrom double count) {
+        if (count < this.value) {
+            this.value = count;
+        }
+    }
+
+    @Override public final void combine(Metrics metrics) {
+        MinDoubleMetrics minDoubleMetrics = (MinDoubleMetrics)metrics;
+        combine(minDoubleMetrics.value);
+    }
+
+    @Override public void calculate() {
+    }
+}

oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/metrics/MinLongMetrics.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.server.core.analysis.metrics;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.Entrance;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.MetricsFunction;
+import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.SourceFrom;
+import org.apache.skywalking.oap.server.core.storage.annotation.Column;
+
+/**
+ * @author jian.tan
+ */
+
+@MetricsFunction(functionName = "min")
+public abstract class MinLongMetrics extends Metrics implements LongValueHolder {
+
+    protected static final String VALUE = "value";
+
+    @Getter @Setter @Column(columnName = VALUE, isValue = true) private long value = Long.MAX_VALUE;
+
+    @Entrance
+    public final void combine(@SourceFrom long count) {
+        if (count < this.value) {
+            this.value = count;
+        }
+    }
+
+    @Override public final void combine(Metrics metrics) {
+        MinLongMetrics minLongMetrics = (MinLongMetrics)metrics;
+        combine(minLongMetrics.value);
+    }
+
+    @Override public void calculate() {
+    }
+}

oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/analysis/metrics/MaxLongMetricsTest.java

@@ -44,8 +44,8 @@ public class MaxLongMetricsTest {
         impl.combine(5);
 
         MaxLongMetricsImpl impl2 = new MaxLongMetricsImpl();
-        impl.combine(2);
-        impl.combine(6);
+        impl2.combine(2);
+        impl2.combine(6);
 
         impl.combine(impl2);
         Assert.assertEquals(10, impl.getValue());

oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/analysis/metrics/MinLongMetricsTest.java

@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.server.core.analysis.metrics;
+
+import org.apache.skywalking.oap.server.core.remote.grpc.proto.RemoteData;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author jian.tan
+ */
+
+public class MinLongMetricsTest {
+
+    @Test
+    public void testEntranceCombine() {
+        MinLongMetricsImpl impl = new MinLongMetricsImpl();
+        impl.combine(10);
+        impl.combine(5);
+        impl.combine(20);
+        impl.calculate();
+        Assert.assertEquals(5, impl.getValue());
+
+        MinLongMetricsImpl impl2 = new MinLongMetricsImpl();
+        impl2.combine(10);
+        impl2.combine(0);
+        impl2.combine(10000);
+        impl2.calculate();
+
+        Assert.assertEquals(0, impl2.getValue());
+    }
+
+    @Test
+    public void testSelfCombine() {
+        MinLongMetricsImpl impl = new MinLongMetricsImpl();
+        impl.combine(10);
+        impl.combine(5);
+
+        MinLongMetricsImpl impl2 = new MinLongMetricsImpl();
+        impl2.combine(2);
+        impl2.combine(6);
+
+        impl.combine(impl2);
+        Assert.assertEquals(2, impl.getValue());
+    }
+
+    public class MinLongMetricsImpl extends MinLongMetrics {
+
+        @Override public String id() {
+            return null;
+        }
+
+        @Override public Metrics toHour() {
+            return null;
+        }
+
+        @Override public Metrics toDay() {
+            return null;
+        }
+
+        @Override public Metrics toMonth() {
+            return null;
+        }
+
+        @Override public int remoteHashCode() {
+            return 0;
+        }
+
+        @Override public void deserialize(RemoteData remoteData) {
+
+        }
+
+        @Override public RemoteData.Builder serialize() {
+            return null;
+        }
+    }
+}