从flink复制部分代码

docs/dev-guide/stream/windowing.md

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+# 窗口函数
+
+## WindowOperator
+
+1. 先为元素分配一组窗口
+2. 针对每个窗口，检查trigger是否触发，并修改timer状态
+3. timer触发时，同样是检查trigger是否触发
+
+```javascript
+void processElement(StreamRecord<IN> element){
+   const elementWindows = windowAssigner.assignWindows(
+                        element.getValue(), element.getTimestamp(), windowAssignerContext);
+   for (const window of elementWindows) {
+        TriggerResult triggerResult = triggerContext.onElement(element);
+
+        if (triggerResult.isFire()) {
+            ACC contents = windowState.get();
+            if (contents != null) {
+                emitWindowContents(actualWindow, contents);
+            }
+        }
+
+        if (triggerResult.isPurge()) {
+            windowState.clear();
+        }
+        registerCleanupTimer(actualWindow);
+   }
+}
+
+void onEventTime(InternalTimer<K, W> timer) {
+    triggerContext.key = timer.getKey();
+    triggerContext.window = timer.getNamespace();
+
+    MergingWindowSet<W> mergingWindows;
+
+    if (windowAssigner instanceof MergingWindowAssigner) {
+        mergingWindows = getMergingWindowSet();
+        W stateWindow = mergingWindows.getStateWindow(triggerContext.window);
+        if (stateWindow == null) {
+            // Timer firing for non-existent window, this can only happen if a
+            // trigger did not clean up timers. We have already cleared the merging
+            // window and therefore the Trigger state, however, so nothing to do.
+            return;
+        } else {
+            windowState.setCurrentNamespace(stateWindow);
+        }
+    } else {
+        windowState.setCurrentNamespace(triggerContext.window);
+        mergingWindows = null;
+    }
+
+    TriggerResult triggerResult = triggerContext.onEventTime(timer.getTimestamp());
+
+    if (triggerResult.isFire()) {
+        ACC contents = windowState.get();
+        if (contents != null) {
+            emitWindowContents(triggerContext.window, contents);
+        }
+    }
+
+    if (triggerResult.isPurge()) {
+        windowState.clear();
+    }
+
+    if (windowAssigner.isEventTime()
+            && isCleanupTime(triggerContext.window, timer.getTimestamp())) {
+        clearAllState(triggerContext.window, windowState, mergingWindows);
+    }
+
+    if (mergingWindows != null) {
+        // need to make sure to update the merging state in state
+        mergingWindows.persist();
+    }
+}
+```
+
+EvictorWindowOperator和WindowOperator的区别仅在于emit的时候是否调用evictor来删除窗口。

nop-cluster/nop-cluster-core/src/main/java/io/nop/cluster/resources/CPUResource.java

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+/*
+ * 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 io.nop.cluster.resources;
+
+import java.math.BigDecimal;
+
+import static java.math.BigDecimal.ROUND_HALF_UP;
+
+/**
+ * Represents CPU resource.
+ */
+public class CPUResource extends Resource<CPUResource> {
+
+    private static final long serialVersionUID = 7228645888210984393L;
+
+    public static final String NAME = "CPU";
+
+    public CPUResource(double value) {
+        super(NAME, value);
+    }
+
+    private CPUResource(BigDecimal value) {
+        super(NAME, value);
+    }
+
+    @Override
+    public CPUResource create(BigDecimal value) {
+        return new CPUResource(value);
+    }
+
+    public String toHumanReadableString() {
+        return String.format(
+                "%.2f cores", getValue().setScale(2, ROUND_HALF_UP).stripTrailingZeros());
+    }
+}

nop-cluster/nop-cluster-core/src/main/java/io/nop/cluster/resources/ExternalResource.java

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+/*
+ * 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 io.nop.cluster.resources;
+
+import java.math.BigDecimal;
+
+/**
+ * An external resource.
+ */
+public class ExternalResource extends Resource<ExternalResource> {
+    private static final long serialVersionUID = 1L;
+
+    public ExternalResource(String name, double value) {
+        super(name, value);
+    }
+
+    private ExternalResource(String name, BigDecimal value) {
+        super(name, value);
+    }
+
+    @Override
+    protected ExternalResource create(BigDecimal value) {
+        return new ExternalResource(getName(), value);
+    }
+}