New HDFSContextClassLoaderFactory

modules/classloaders/hdfs-class-loader/pom.xml

@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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
+
+      https://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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.apache.accumulo</groupId>
+    <artifactId>classloader-extras</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <relativePath>../../../pom.xml</relativePath>
+  </parent>
+  <artifactId>hdfs-class-loader</artifactId>
+  <properties>
+    <eclipseFormatterStyle>../../../src/build/eclipse-codestyle.xml</eclipseFormatterStyle>
+    <maven.test.redirectTestOutputToFile>true</maven.test.redirectTestOutputToFile>
+  </properties>
+  <dependencies>
+    <dependency>
+      <!-- needed for build checks, but not for runtime -->
+      <groupId>com.github.spotbugs</groupId>
+      <artifactId>spotbugs-annotations</artifactId>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>commons-io</groupId>
+      <artifactId>commons-io</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>org.apache.accumulo</groupId>
+      <artifactId>accumulo-core</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-client-api</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <!-- provided by accumulo -->
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-client-minicluster</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-slf4j2-impl</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>build-test-jars</id>
+            <goals>
+              <goal>exec</goal>
+            </goals>
+            <phase>process-test-classes</phase>
+            <configuration>
+              <executable>../jar-creation/shell/makeTestJars.sh</executable>
+            </configuration>
+          </execution>
+          <execution>
+            <id>build-helloworld-jars</id>
+            <goals>
+              <goal>exec</goal>
+            </goals>
+            <phase>process-test-classes</phase>
+            <configuration>
+              <executable>../jar-creation/shell/makeHelloWorldJars.sh</executable>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

modules/classloaders/hdfs-class-loader/src/main/java/org/apache/accumulo/classloader/hdfs/ClassLoaderStore.java

@@ -0,0 +1,62 @@
+/*
+ * 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
+ *
+ *   https://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.accumulo.classloader.hdfs;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.function.BiFunction;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+public class ClassLoaderStore<K,V> {
+  private final ConcurrentMap<K,V> store = new ConcurrentHashMap<>();
+  private final Consumer<Map.Entry<K,V>> onRemove;
+
+  public ClassLoaderStore(Consumer<Map.Entry<K,V>> onRemove) {
+    this.onRemove = onRemove;
+  }
+
+  public V get(K key) {
+    return store.get(key);
+  }
+
+  public boolean isEmpty() {
+    return store.isEmpty();
+  }
+
+  public V computeIfPresent(K key, BiFunction<? super K,? super V,? extends V> remappingFunction) {
+    return store.computeIfPresent(key, remappingFunction);
+  }
+
+  public V computeIfAbsent(K key, Function<? super K,? extends V> mappingFunction) {
+    return store.computeIfAbsent(key, mappingFunction);
+  }
+
+  public void removeIf(Predicate<Map.Entry<K,V>> predicate) {
+    store.entrySet().removeIf(entry -> {
+      if (predicate.test(entry)) {
+        onRemove.accept(entry);
+        return true;
+      }
+      return false;
+    });
+  }
+}