#3 thread safety

pom.xml

@@ -90,12 +90,12 @@ SOFTWARE.
     <dependency>
       <groupId>org.cactoos</groupId>
       <artifactId>cactoos</artifactId>
-      <version>0.25.3</version>
+      <version>0.42</version>
     </dependency>
     <dependency>
       <groupId>com.jcabi</groupId>
       <artifactId>jcabi-xml</artifactId>
-      <version>0.17.2</version>
+      <version>0.22.1</version>
     </dependency>
     <dependency>
       <groupId>javax.xml.bind</groupId>
@@ -105,6 +105,7 @@ SOFTWARE.
     <dependency>
       <groupId>com.jcabi</groupId>
       <artifactId>jcabi-log</artifactId>
+      <version>0.18.1</version>
     </dependency>
     <dependency>
       <groupId>com.jcabi</groupId>

src/main/java/com/yegor256/rpm/Pkg.java

@@ -31,8 +31,8 @@
 import java.nio.file.Path;
 import java.util.logging.Level;
 import org.cactoos.Scalar;
-import org.cactoos.scalar.StickyScalar;
-import org.cactoos.scalar.UncheckedScalar;
+import org.cactoos.scalar.Sticky;
+import org.cactoos.scalar.Unchecked;
 import org.redline_rpm.ReadableChannelWrapper;
 import org.redline_rpm.Scanner;
 import org.redline_rpm.header.AbstractHeader;
@@ -56,16 +56,16 @@ final class Pkg {
     /**
      * The header.
      */
-    private final UncheckedScalar<Header> hdr;
+    private final Unchecked<Header> hdr;
 
     /**
      * Ctor.
      * @param path The path
      */
     Pkg(final Path path) {
         this.file = path;
-        this.hdr = new UncheckedScalar<>(
-            new StickyScalar<>(
+        this.hdr = new Unchecked<>(
+            new Sticky<>(
                 new Scalar<Header>() {
                     @Override
                     public Header value() throws Exception {

src/main/java/com/yegor256/rpm/Rpm.java

@@ -70,22 +70,24 @@ public Rpm(final Storage stg) {
      * @throws IOException If fails
      */
     public void update(final String key) throws IOException {
-        final Path temp = Files.createTempFile("rpm", ".rpm");
-        this.storage.load(key, temp);
-        final Pkg pkg = new Pkg(temp);
-        final Repomd repomd = new Repomd(this.storage);
-        repomd.update(
-            "primary",
-            file -> new Primary(file).update(key, pkg)
-        );
-        repomd.update(
-            "filelists",
-            file -> new Filelists(file).update(pkg)
-        );
-        repomd.update(
-            "other",
-            file -> new Other(file).update(pkg)
-        );
+        synchronized (this.storage) {
+            final Path temp = Files.createTempFile("rpm", ".rpm");
+            this.storage.load(key, temp);
+            final Pkg pkg = new Pkg(temp);
+            final Repomd repomd = new Repomd(this.storage);
+            repomd.update(
+                "primary",
+                file -> new Primary(file).update(key, pkg)
+            );
+            repomd.update(
+                "filelists",
+                file -> new Filelists(file).update(pkg)
+            );
+            repomd.update(
+                "other",
+                file -> new Other(file).update(pkg)
+            );
+        }
     }
 
 }

src/test/java/com/yegor256/rpm/RpmTest.java

@@ -0,0 +1,102 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.yegor256.rpm;
+
+import com.jcabi.matchers.XhtmlMatchers;
+import com.jcabi.xml.XMLDocument;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import org.cactoos.Scalar;
+import org.cactoos.experimental.Threads;
+import org.cactoos.iterable.Repeated;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+/**
+ * Test case for {@link Rpm}.
+ *
+ * @author Yegor Bugayenko ([email protected])
+ * @version $Id$
+ * @since 0.0.3
+ */
+public final class RpmTest {
+
+    /**
+     * Temp folder for all tests.
+     */
+    @Rule
+    @SuppressWarnings("PMD.BeanMembersShouldSerialize")
+    public TemporaryFolder folder = new TemporaryFolder();
+
+    /**
+     * Rpm storage works, in many threads.
+     * @throws Exception If some problem inside
+     */
+    @Test
+    @SuppressWarnings("unchecked")
+    public void addsSingleRpm() throws Exception {
+        final Storage storage = new Storage.Simple(
+            this.folder.newFolder().toPath()
+        );
+        final Path bin = this.folder.newFile("x.rpm").toPath();
+        final String key = "nginx-module-xslt-1.16.1-1.el7.ngx.x86_64.rpm";
+        Files.copy(
+            RpmITCase.class.getResourceAsStream(
+                String.format("/%s", key)
+            ),
+            bin,
+            StandardCopyOption.REPLACE_EXISTING
+        );
+        storage.save(key, bin);
+        final Rpm rpm = new Rpm(storage);
+        final int threads = 10;
+        MatcherAssert.assertThat(
+            new Threads<>(
+                threads,
+                new Repeated<Scalar<Boolean>>(
+                    threads,
+                    () -> {
+                        rpm.update(key);
+                        return true;
+                    }
+                )
+            ),
+            Matchers.iterableWithSize(threads)
+        );
+        final Path primary = this.folder.newFile("primary.xml").toPath();
+        storage.load("repodata/primary.xml", primary);
+        MatcherAssert.assertThat(
+            new XMLDocument(new String(Files.readAllBytes(primary))),
+            XhtmlMatchers.hasXPath(
+                "/ns1:metadata/ns1:package[ns1:name='nginx-module-xslt']",
+                "http://linux.duke.edu/metadata/common"
+            )
+        );
+    }
+
+}