Implements an ArrowRootAllocationProvider spi

pom.xml

@@ -51,6 +51,7 @@
     <EMISSARY_VERSION>${project.version}</EMISSARY_VERSION>
     <argLine />
     <checkstyleFormatter>${project.basedir}/contrib/checkstyle.xml</checkstyleFormatter>
+    <dep.arrow.version>16.1.0</dep.arrow.version>
     <dep.commons-codec.version>1.16.0</dep.commons-codec.version>
     <dep.commons-collections.version>4.4</dep.commons-collections.version>
     <dep.commons-compress.version>1.27.1</dep.commons-compress.version>
@@ -197,6 +198,16 @@
         <artifactId>spymemcached</artifactId>
         <version>${dep.spymemcached.version}</version>
       </dependency>
+      <dependency>
+        <groupId>org.apache.arrow</groupId>
+        <artifactId>arrow-memory-core</artifactId>
+        <version>${dep.arrow.version}</version>
+      </dependency>
+      <dependency>
+        <groupId>org.apache.arrow</groupId>
+        <artifactId>arrow-memory-netty</artifactId>
+        <version>${dep.arrow.version}</version>
+      </dependency>
       <dependency>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-collections4</artifactId>
@@ -401,6 +412,17 @@
       <groupId>net.spy</groupId>
       <artifactId>spymemcached</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.arrow</groupId>
+      <artifactId>arrow-memory-core</artifactId>
+      <exclusions>
+        <!-- conflicts with guava's dependency, which is an older version of the checker framework -->
+        <exclusion>
+          <groupId>org.checkerframework</groupId>
+          <artifactId>checker-qual</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
     <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-collections4</artifactId>
@@ -523,6 +545,13 @@
       <artifactId>error_prone_annotations</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.arrow</groupId>
+      <artifactId>arrow-memory-netty</artifactId>
+      <scope>test</scope>
+      <!-- consumers of emissary can use either arrow-memory-netty or arrow-memory-unsafe to provide an allocator -->
+      <optional>true</optional>
+    </dependency>
     <dependency>
       <groupId>org.glassfish.jersey.test-framework.providers</groupId>
       <artifactId>jersey-test-framework-provider-jetty</artifactId>
@@ -1018,6 +1047,10 @@
                 </resources>
               </exception>
             </exceptions>
+            <ignoredResourcePatterns>
+              <!-- arrow puts this in every jar -->
+              <ignoredResourcePattern>arrow-git.properties</ignoredResourcePattern>
+            </ignoredResourcePatterns>
             <printEqualFiles>false</printEqualFiles>
             <failBuildInCaseOfDifferentContentConflict>true</failBuildInCaseOfDifferentContentConflict>
             <failBuildInCaseOfEqualContentConflict>true</failBuildInCaseOfEqualContentConflict>

src/main/java/emissary/spi/ArrowRootAllocatorProvider.java

@@ -0,0 +1,38 @@
+package emissary.spi;
+
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.RootAllocator;
+
+public class ArrowRootAllocatorProvider implements InitializationProvider {
+
+    private static final Object initalizationLock = new Object();
+    private static BufferAllocator arrowRootAllocator = null;
+
+    @Override
+    public void initialize() {
+        synchronized (initalizationLock) {
+            arrowRootAllocator = new RootAllocator();
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        synchronized (initalizationLock) {
+            arrowRootAllocator.close();
+            arrowRootAllocator = null;
+        }
+        InitializationProvider.super.shutdown();
+    }
+
+    public static BufferAllocator getArrowRootAllocator() {
+        synchronized (initalizationLock) {
+            if (arrowRootAllocator == null) {
+                throw new IllegalStateException("Arrow Root Allocator has not been initalized by the " +
+                        "ArrowRootAllocatorProvider or is already shutdown, is emissary.spi.ArrowRootAllocatorProver " +
+                        "listed in META-INF/services/emissary.spi.InitalizationProvider?");
+            } else {
+                return arrowRootAllocator;
+            }
+        }
+    }
+}

src/main/resources/META-INF/services/emissary.spi.InitializationProvider

@@ -1,2 +1,3 @@
 emissary.spi.JavaCharSetInitializationProvider
 emissary.spi.ClassLocationVerificationProvider
+emissary.spi.ArrowRootAllocatorProvider

src/test/java/emissary/spi/ArrowRootAllocatorProviderTest.java

@@ -0,0 +1,30 @@
+package emissary.spi;
+
+import emissary.test.core.junit5.UnitTest;
+
+import org.apache.arrow.memory.BufferAllocator;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class ArrowRootAllocatorProviderTest extends UnitTest {
+    @Test
+    public void testArrowRootAllocatorProvider() {
+        ArrowRootAllocatorProvider provider = new ArrowRootAllocatorProvider();
+        provider.initialize();
+        BufferAllocator allocator = ArrowRootAllocatorProvider.getArrowRootAllocator();
+        assertNotNull(allocator);
+    }
+
+    @Test()
+    public void testArrowRootAllocatorProviderAfterShutdown() {
+        ArrowRootAllocatorProvider provider = new ArrowRootAllocatorProvider();
+        provider.initialize();
+        BufferAllocator allocatorOne = ArrowRootAllocatorProvider.getArrowRootAllocator();
+        assertNotNull(allocatorOne);
+        provider.shutdown();
+        assertThrows(IllegalStateException.class, ArrowRootAllocatorProvider::getArrowRootAllocator, "expected IllegalStateException");
+    }
+}
+