Github user ottobackwards commented on a diff in the pull request:
https://github.com/apache/metron/pull/867#discussion_r156790508
--- Diff:
metron-analytics/metron-statistics/src/main/java/org/apache/metron/statistics/sampling/SamplingInitFunctions.java
---
@@ -0,0 +1,89 @@
+/*
+ *
+ * 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.metron.statistics.sampling;
+
+import org.apache.metron.stellar.common.utils.ConversionUtils;
+import org.apache.metron.stellar.dsl.Context;
+import org.apache.metron.stellar.dsl.ParseException;
+import org.apache.metron.stellar.dsl.Stellar;
+import org.apache.metron.stellar.dsl.StellarFunction;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class SamplingInitFunctions {
+
+ @Stellar(namespace="SAMPLE"
+ ,name="INIT"
+ ,description="Create a uniform reservoir sampler of a specific
size or, if unspecified, size " + Sampler.DEFAULT_SIZE
+ ,params = {
+ "size? - The size of the reservoir sampler. If unspecified,
the size is " + Sampler.DEFAULT_SIZE
+ }
+ ,returns="The sampler object."
+ )
+
+ public static class UniformSamplerInit implements StellarFunction {
+ @Override
+ public Object apply(List<Object> args, Context context) throws
ParseException {
+ if(args.size() == 0) {
+ return new UniformSampler();
+ }
+ else {
+ Optional<Integer> sizeArg = get(args, 0, "Size", Integer.class);
+ if(sizeArg.isPresent() && sizeArg.get() <= 0) {
+ throw new IllegalStateException("Size must be a positive
integer");
+ }
+ else {
+ return new UniformSampler(sizeArg.orElse(Sampler.DEFAULT_SIZE));
+ }
+ }
+ }
+
+ @Override
+ public void initialize(Context context) {
+ }
+
+ @Override
+ public boolean isInitialized() {
+ return true;
+ }
+ }
+
+
+ public static <T> Optional<T> get(List<Object> args, int offset, String
argName, Class<T> expectedClazz) {
+ Object obj = args.get(offset);
+ T ret = ConversionUtils.convert(obj, expectedClazz);
--- End diff --
Couldn't this be simplified to :
```java
if(ret == null ) {
if(obj != null) {
throw new IllegalStateException(argName + "argument(" + obj
+ " is expected to be an " +
expectedClazz.getName()
+ ", but was " + obj
);
}
}
return Optional.ofNullable(ret);
}
```
---
