Introduce JarEntries, tests and io.smallrye.common.io.jar package

io/pom.xml

@@ -13,6 +13,36 @@
     <artifactId>smallrye-common-io</artifactId>
     <name>SmallRye Common: IO</name>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.jboss.shrinkwrap</groupId>
+            <artifactId>shrinkwrap-depchain</artifactId>
+            <type>pom</type>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-failsafe-plugin</artifactId>
+                <version>3.0.0-M5</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>integration-test</goal>
+                            <goal>verify</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
     <profiles>
         <profile>
             <id>coverage</id>

io/src/main/java/io/smallrye/common/io/jar/JarEntries.java

@@ -0,0 +1,13 @@
+package io.smallrye.common.io.jar;
+
+import java.util.jar.JarEntry;
+
+public class JarEntries {
+    /**
+     * Returns the real name of this {@link JarEntry}. On Java 8, it returns the {@link JarEntry#getName()}
+     * On Java 10+, a getRealName() method was added
+     */
+    public static String getRealName(JarEntry jarEntry) {
+        return jarEntry.getName();
+    }
+}

io/src/main/java/io/smallrye/common/io/JarFiles.java → io/src/main/java/io/smallrye/common/io/jar/JarFiles.java

@@ -1,8 +1,10 @@
-package io.smallrye.common.io;
+package io.smallrye.common.io.jar;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.util.jar.JarFile;
+import java.util.jar.Manifest;
 
 /**
  * Java 8 variant of a JDK-specific class for working with {@code JarFile}s.
@@ -39,4 +41,21 @@ public static JarFile create(File file) throws IOException {
     public static JarFile create(File file, boolean verify) throws IOException {
         return new JarFile(file, verify);
     }
+
+    /**
+     * Returns true if this {@link JarFile} is a multi-release jar. On Java 8 this is done by browsing the manifest.
+     * On Java 9+, there is a isMultiRelease method
+     */
+    public static boolean isMultiRelease(JarFile jarFile) {
+        String value = null;
+        try {
+            Manifest manifest = jarFile.getManifest();
+            if (manifest != null) {
+                value = manifest.getMainAttributes().getValue("Multi-Release");
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException("Cannot read manifest attributes", e);
+        }
+        return Boolean.parseBoolean(value);
+    }
 }

io/src/main/java10/io/smallrye/common/io/jar/JarEntries.java

@@ -0,0 +1,13 @@
+package io.smallrye.common.io.jar;
+
+import java.util.jar.JarEntry;
+
+public class JarEntries {
+    /**
+     * Returns the real name of this {@link JarEntry}. On Java 8, it returns the {@link JarEntry#getName()}
+     * On Java 10+, a getRealName() method was added
+     */
+    public static String getRealName(JarEntry jarEntry) {
+        return jarEntry.getRealName();
+    }
+}

io/src/main/java9/io/smallrye/common/io/jar/JarEntries.java

@@ -0,0 +1,36 @@
+package io.smallrye.common.io.jar;
+
+import java.lang.reflect.Method;
+import java.util.jar.JarEntry;
+
+public class JarEntries {
+
+    private static final Method REAL_NAME_METHOD;
+
+    static {
+        Method method;
+        try {
+            method = Class.forName("java.util.jar.JarFile$JarFileEntry").getDeclaredMethod("realName");
+            method.setAccessible(true);
+        } catch (NoSuchMethodException | ClassNotFoundException e) {
+            method = null;
+        }
+        REAL_NAME_METHOD = method;
+    }
+
+    /**
+     * Returns the real name of this {@link JarEntry}. On Java 8, it returns the {@link JarEntry#getName()}
+     * On Java 10+, a getRealName() method was added
+     */
+    public static String getRealName(JarEntry jarEntry) {
+        if (REAL_NAME_METHOD != null) {
+            try {
+                return REAL_NAME_METHOD.invoke(jarEntry).toString();
+            } catch (Exception e) {
+                // This should never happen
+            }
+        }
+        // As a safe net, fallback to the original value
+        return jarEntry.getName();
+    }
+}

io/src/main/java9/io/smallrye/common/io/JarFiles.java → io/src/main/java9/io/smallrye/common/io/jar/JarFiles.java

@@ -1,4 +1,4 @@
-package io.smallrye.common.io;
+package io.smallrye.common.io.jar;
 
 import java.io.File;
 import java.io.IOException;
@@ -40,4 +40,13 @@ public static JarFile create(File file) throws IOException {
     public static JarFile create(File file, boolean verify) throws IOException {
         return new JarFile(file, verify, ZipFile.OPEN_READ, JarFile.runtimeVersion());
     }
+
+    /**
+     * Returns true if this {@link JarFile} is a multi-release jar. On Java 8 this is done by browsing the manifest.
+     * On Java 9+, there is a isMultiRelease method
+     */
+    public static boolean isMultiRelease(JarFile jarFile) {
+        return jarFile.isMultiRelease();
+    }
+
 }

io/src/test/java/io/smallrye/common/io/jar/JarEntriesIT.java

@@ -0,0 +1,36 @@
+package io.smallrye.common.io.jar;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnJre;
+import org.junit.jupiter.api.condition.EnabledOnJre;
+import org.junit.jupiter.api.condition.JRE;
+
+// This needs to be run as an integration-test
+public class JarEntriesIT {
+
+    @Test
+    @DisabledOnJre(JRE.JAVA_8)
+    public void shouldUseMultiReleaseName() throws IOException {
+        File tmpFile = JarGenerator.generateMultiReleaseJar();
+        JarFile jarFile = JarFiles.create(tmpFile);
+        JarEntry jarEntry = jarFile.getJarEntry("foo.txt");
+        assertEquals("META-INF/versions/9/foo.txt", JarEntries.getRealName(jarEntry));
+    }
+
+    @Test
+    @EnabledOnJre(JRE.JAVA_8)
+    public void shouldUseName() throws IOException {
+        File tmpFile = JarGenerator.generateMultiReleaseJar();
+        JarFile jarFile = JarFiles.create(tmpFile);
+        JarEntry jarEntry = jarFile.getJarEntry("foo.txt");
+        assertEquals("foo.txt", JarEntries.getRealName(jarEntry));
+    }
+
+}

io/src/test/java/io/smallrye/common/io/jar/JarFilesTest.java

@@ -0,0 +1,28 @@
+package io.smallrye.common.io.jar;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.jar.JarFile;
+
+import org.junit.jupiter.api.Test;
+
+public class JarFilesTest {
+
+    @Test
+    public void shouldReadPlainJars() throws IOException {
+        File tmpFile = JarGenerator.generatePlainJar();
+        JarFile jarFile = JarFiles.create(tmpFile);
+        assertFalse(JarFiles.isMultiRelease(jarFile));
+    }
+
+    @Test
+    public void shouldReadMultiReleaseJars() throws IOException {
+        File tmpFile = JarGenerator.generateMultiReleaseJar();
+        JarFile jarFile = JarFiles.create(tmpFile);
+        assertTrue(JarFiles.isMultiRelease(jarFile));
+    }
+
+}

io/src/test/java/io/smallrye/common/io/jar/JarGenerator.java

@@ -0,0 +1,29 @@
+package io.smallrye.common.io.jar;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.jboss.shrinkwrap.api.exporter.ZipExporter;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+
+public class JarGenerator {
+    public static File generatePlainJar() throws IOException {
+        JavaArchive jar = ShrinkWrap.create(JavaArchive.class)
+                .addAsResource(new StringAsset("Original"), "foo.txt");
+        File tmpFile = File.createTempFile("tmp", ".tmp");
+        jar.as(ZipExporter.class).exportTo(tmpFile, true);
+        return tmpFile;
+    }
+
+    public static File generateMultiReleaseJar() throws IOException {
+        JavaArchive jar = ShrinkWrap.create(JavaArchive.class)
+                .addAsManifestResource(new StringAsset("Multi-Release: true\n"), "MANIFEST.MF")
+                .addAsResource(new StringAsset("Original"), "foo.txt")
+                .addAsManifestResource(new StringAsset("MultiRelease"), "versions/9/foo.txt");
+        File tmpFile = File.createTempFile("tmp", ".tmp");
+        jar.as(ZipExporter.class).exportTo(tmpFile, true);
+        return tmpFile;
+    }
+}

pom.xml

@@ -71,6 +71,13 @@
             </dependency>
 
             <!-- External test dependencies -->
+            <dependency>
+                <groupId>org.jboss.shrinkwrap</groupId>
+                <artifactId>shrinkwrap-bom</artifactId>
+                <version>1.2.6</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
 
 
             <!-- Internal module dependencies -->