<artifactId>aid</artifactId>
  <groupId>gid</groupId>
  <version>0.1</version>

  <dependencies>
    <dependency>
      <groupId>test</groupId>
      <artifactId>a</artifactId>
      <version>0.2</version>
      <scope>system</scope>
      <systemPath>${basedir}/lib/a.jar</systemPath>
    </dependency>
    <dependency>
      <groupId>test</groupId>
      <artifactId>b</artifactId>

    }

    @Override
    public Object get(String groupId, String artifactId, String version, String tag) {
        return cache.get(session, new Key(groupId, artifactId, version, tag));
    }

    @Override
    public void put(String groupId, String artifactId, String version, String tag, Object data) {
        cache.put(session, new Key(groupId, artifactId, version, tag), data);
    }

    static class Key {

    <modelVersion>4.0.0</modelVersion>

    <groupId>org.junit</groupId>
    <artifactId>bom</artifactId>
    <version>0.1</version>
    <packaging>pom</packaging>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.junit</groupId>
                <artifactId>junit</artifactId>
                <version>0.1</version>

     */
    public String getGroupId() {
        return (groupId != null) ? groupId : "";
    }

    /**
     * Sets the effective group identifier of the model.
     *
     * @param groupId The effective group identifier of the model, may be {@code null}.
     */
    public void setGroupId(String groupId) {
        this.groupId = groupId;
    }

    /**

  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>ut.simple</groupId>
    <artifactId>parent</artifactId>
    <version>1.0</version>
  </parent>

  <artifactId>artifact</artifactId>

  <name>Simple Unit Test Artifact</name>

  <dependencies>
    <dependency>
      <groupId>ut.simple</groupId>
      <artifactId>dependency</artifactId>
    </dependency>
    <dependency>

-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>aid</artifactId>
  <groupId>gid</groupId>
  <version>0.1</version>

  <dependencies>
    <dependency>
      <groupId>test</groupId>
      <artifactId>a</artifactId>
      <version>0.2</version>
    </dependency>
    <dependency>
      <groupId>test</groupId>
      <artifactId>b</artifactId>
      <version>${missing.property}</version>
    </dependency>

    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-xml</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.modello</groupId>
        <artifactId>modello-maven-plugin</artifactId>
        <configuration>
          <version>4.2.0</version>

    }

    public static String versionlessKey(String groupId, String artifactId) {
        notBlank(groupId, "groupId can neither be null, empty nor blank");
        notBlank(artifactId, "artifactId can neither be null, empty nor blank");

        return groupId + ":" + artifactId;
    }

    public static String key(Artifact artifact) {

  <groupId>maven-test</groupId>
  <artifactId>t06-b</artifactId>
  <packaging>jar</packaging>
  <version>1.0</version>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t06-c</artifactId>
      <version>1.0</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>maven-test</groupId>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <artifactId>artifactId</artifactId>
        <groupId>groupId</groupId>
      </dependency>
    </dependencies>
  </dependencyManagement>