[MENFORCER-422] Added descriptors rule

.gitignore

@@ -6,4 +6,4 @@ target
 .svn
 *.iml
 .checkstyle
-
+.DS_Store

enforcer-rules/src/main/java/org/apache/maven/plugins/enforcer/Descriptors.java

@@ -0,0 +1,148 @@
+package org.apache.maven.plugins.enforcer;
+
+/*
+ * 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
+ *
+ *  http://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.
+ */
+
+import org.apache.maven.enforcer.rule.api.EnforcerRule;
+import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
+import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
+import org.apache.maven.plugin.MojoExecution;
+import org.codehaus.plexus.classworlds.realm.ClassRealm;
+import org.codehaus.plexus.component.configurator.ComponentConfigurator;
+import org.codehaus.plexus.configuration.PlexusConfiguration;
+import org.codehaus.plexus.configuration.xml.XmlPlexusConfiguration;
+import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
+import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+
+/**
+ * An enforcer rule that will invoke rules from an external resource
+ *
+ * @author <a href="mailto:[email protected]">George Gastaldi</a>
+ */
+public class Descriptors extends AbstractNonCacheableEnforcerRule
+{
+    String descriptorRef;
+
+    String descriptor;
+
+    @Override
+    public void execute( EnforcerRuleHelper helper ) throws EnforcerRuleException
+    {
+        // Find descriptor
+        EnforcerDescriptor enforcerDescriptor = getEnforcerDescriptor( helper );
+        for ( EnforcerRule rule : enforcerDescriptor.getRules() )
+        {
+            rule.execute( helper );
+        }
+    }
+
+    /**
+     * Resolve the {@link EnforcerDescriptor} based on the provided {@link #descriptor} or {@link #descriptorRef}
+     *
+     * @param helper used to build the {@link EnforcerDescriptor}
+     * @return an {@link EnforcerDescriptor} for this rule
+     * @throws EnforcerRuleException if any failure happens while reading the descriptor
+     */
+    EnforcerDescriptor getEnforcerDescriptor( EnforcerRuleHelper helper )
+            throws EnforcerRuleException
+    {
+        try ( InputStream descriptorStream = resolveDescriptor( helper ) )
+        {
+            EnforcerDescriptor descriptor = new EnforcerDescriptor();
+            // To get configuration from the enforcer-plugin mojo do:
+            //helper.evaluate(helper.getComponent(MojoExecution.class).getConfiguration().getChild("fail").getValue())
+            // Get the enforcer plugin's class resolver
+            ClassRealm realm = helper.getComponent( MojoExecution.class ).getMojoDescriptor().getRealm();
+            ComponentConfigurator configurator = helper.getComponent( ComponentConfigurator.class, "basic" );
+            // Configure EnforcerDescriptor from the XML
+            configurator.configureComponent( descriptor, toPlexusConfiguration( descriptorStream ), helper, realm );
+            return descriptor;
+        }
+        catch ( EnforcerRuleException e )
+        {
+            throw e;
+        }
+        catch ( Exception e )
+        {
+            throw new EnforcerRuleException( "Error while enforcing rules", e );
+        }
+    }
+
+    private InputStream resolveDescriptor( EnforcerRuleHelper helper ) throws EnforcerRuleException
+    {
+        InputStream descriptorStream;
+        if ( descriptorRef != null )
+        {
+            descriptorStream = Thread.currentThread().getContextClassLoader()
+                    .getResourceAsStream( "enforcer-rules/" + descriptorRef + ".xml" );
+            if ( descriptorStream == null )
+            {
+                throw new EnforcerRuleException( "Descriptor Ref '" + descriptorRef + "' not found" );
+            }
+        }
+        else if ( descriptor != null )
+        {
+            File descriptorFile = helper.alignToBaseDirectory( new File( descriptor ) );
+            try
+            {
+                descriptorStream = Files.newInputStream( descriptorFile.toPath() );
+            }
+            catch ( IOException e )
+            {
+                throw new EnforcerRuleException( "Could not read descriptor in " + descriptorFile, e );
+            }
+        }
+        else
+        {
+            throw new EnforcerRuleException( "No descriptorRef or descriptor provided" );
+        }
+        return descriptorStream;
+    }
+
+    private static PlexusConfiguration toPlexusConfiguration( InputStream descriptorStream )
+            throws XmlPullParserException, IOException
+    {
+        return new XmlPlexusConfiguration( Xpp3DomBuilder.build( descriptorStream, "UTF-8" ) );
+    }
+
+    public void setDescriptorRef( String descriptorRef )
+    {
+        this.descriptorRef = descriptorRef;
+    }
+
+    public String getDescriptorRef()
+    {
+        return descriptorRef;
+    }
+
+    public void setDescriptor( String descriptor )
+    {
+        this.descriptor = descriptor;
+    }
+
+    public String getDescriptor()
+    {
+        return descriptor;
+    }
+}

enforcer-rules/src/main/java/org/apache/maven/plugins/enforcer/EnforcerDescriptor.java

@@ -0,0 +1,42 @@
+package org.apache.maven.plugins.enforcer;
+
+/*
+ * 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
+ *
+ *  http://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.
+ */
+
+import org.apache.maven.enforcer.rule.api.EnforcerRule;
+
+/**
+ * An enforcer rules descriptor used by {@link Descriptors}
+ *
+ * @author <a href="mailto:[email protected]">George Gastaldi</a>
+ */
+public class EnforcerDescriptor
+{
+    EnforcerRule[] rules;
+
+    public EnforcerRule[] getRules()
+    {
+        return rules;
+    }
+
+    public void setRules( EnforcerRule[] rules )
+    {
+        this.rules = rules;
+    }
+}

enforcer-rules/src/test/java/org/apache/maven/plugins/enforcer/TestDescriptors.java

@@ -0,0 +1,58 @@
+package org.apache.maven.plugins.enforcer;
+
+/*
+ * 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
+ *
+ *  http://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.
+ */
+
+import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
+import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+public class TestDescriptors
+{
+    @Test
+    void shouldFailIfNoDescriptorIsSet()
+    {
+        Descriptors rule = new Descriptors();
+        EnforcerRuleHelper helper = EnforcerTestUtils.getHelper();
+        assertThatExceptionOfType( EnforcerRuleException.class ).isThrownBy( () -> rule.execute( helper ) )
+                .withMessage( "No descriptorRef or descriptor provided" );
+    }
+
+    @Test
+    void shouldFailIfRefIsNotFound()
+    {
+        Descriptors rule = new Descriptors();
+        rule.setDescriptorRef( "foo" );
+        EnforcerRuleHelper helper = EnforcerTestUtils.getHelper();
+        assertThatExceptionOfType( EnforcerRuleException.class ).isThrownBy( () -> rule.execute( helper ) )
+                .withMessage( "Descriptor Ref 'foo' not found" );
+    }
+
+    @Test
+    void shouldFailIfDescriptorIsNotFound()
+    {
+        Descriptors rule = new Descriptors();
+        rule.setDescriptor( "blah.xml" );
+        EnforcerRuleHelper helper = EnforcerTestUtils.getHelper();
+        assertThatExceptionOfType( EnforcerRuleException.class ).isThrownBy( () -> rule.execute( helper ) )
+                .withMessageMatching( "Could not read descriptor in .*blah.xml" );
+    }
+}

enforcer-rules/src/test/resources/enforcer-rules/pass.xml

@@ -0,0 +1,26 @@
+<?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
+
+  http://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.
+-->
+
+<enforcer>
+    <rules>
+        <AlwaysPass/>
+    </rules>
+</enforcer>

maven-enforcer-plugin/src/it/projects/descriptors-local-always-fail/enforcer-rules.xml

@@ -0,0 +1,26 @@
+<?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
+
+  http://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.
+-->
+
+<enforcer>
+    <rules>
+        <AlwaysFail/>
+    </rules>
+</enforcer>

maven-enforcer-plugin/src/it/projects/descriptors-local-always-fail/invoker.properties

@@ -0,0 +1,18 @@
+# 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
+#
+#  http://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.
+
+invoker.buildResult = failure

maven-enforcer-plugin/src/it/projects/descriptors-local-always-fail/pom.xml

@@ -0,0 +1,56 @@
+<?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
+
+  http://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>
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.its.enforcer</groupId>
+  <artifactId>test</artifactId>
+  <version>1.0</version>
+
+  <description>
+  </description>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <id>test</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <Descriptors>
+                  <descriptor>enforcer-rules.xml</descriptor>
+                </Descriptors>
+              </rules>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>