[MNG-7486] Create a multiline message helper for boxed log messages

This closes #746

maven-core/src/main/java/org/apache/maven/internal/MultilineMessageHelper.java

@@ -0,0 +1,91 @@
+package org.apache.maven.internal;
+
+/*
+ * 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 java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper class to format multiline messages to the console
+ */
+public class MultilineMessageHelper
+{
+
+    private static final int DEFAULT_MAX_SIZE = 65;
+    private static final char BOX_CHAR = '*';
+
+    public static String separatorLine()
+    {
+        StringBuilder sb = new StringBuilder( DEFAULT_MAX_SIZE );
+        repeat( sb, '*', DEFAULT_MAX_SIZE );
+        return sb.toString();
+    }
+
+    public static List<String> format( String... lines )
+    {
+        int size = DEFAULT_MAX_SIZE;
+        int remainder = size - 4; // 4 chars = 2 box_char + 2 spaces
+        List<String> result = new ArrayList<>();
+        StringBuilder sb = new StringBuilder( size );
+        // first line
+        sb.setLength( 0 );
+        repeat( sb, BOX_CHAR, size );
+        result.add( sb.toString() );
+        // lines
+        for ( String line : lines )
+        {
+            sb.setLength( 0 );
+            String[] words = line.split( "\\s+" );
+            for ( String word : words )
+            {
+                if ( sb.length() >= remainder - word.length() - ( sb.length() > 0 ? 1 : 0 ) )
+                {
+                    repeat( sb, ' ', remainder - sb.length() );
+                    result.add( BOX_CHAR + " " + sb + " " + BOX_CHAR );
+                    sb.setLength( 0 );
+                }
+                if ( sb.length() > 0 )
+                {
+                    sb.append( ' ' );
+                }
+                sb.append( word );
+            }
+
+            while ( sb.length() < remainder )
+            {
+                sb.append( ' ' );
+            }
+            result.add( BOX_CHAR + " " + sb + " " + BOX_CHAR );
+        }
+        // last line
+        sb.setLength( 0 );
+        repeat( sb, BOX_CHAR, size );
+        result.add( sb.toString() );
+        return result;
+    }
+
+    private static void repeat( StringBuilder sb, char c, int nb )
+    {
+        for ( int i = 0; i < nb; i++ )
+        {
+            sb.append( c );
+        }
+    }
+}

maven-core/src/main/java/org/apache/maven/lifecycle/internal/builder/BuilderCommon.java

@@ -24,6 +24,7 @@ import org.apache.maven.execution.BuildFailure;
 import org.apache.maven.execution.ExecutionEvent;
 import org.apache.maven.execution.MavenExecutionRequest;
 import org.apache.maven.execution.MavenSession;
+import org.apache.maven.internal.MultilineMessageHelper;
 import org.apache.maven.lifecycle.LifecycleExecutionException;
 import org.apache.maven.lifecycle.LifecycleNotFoundException;
 import org.apache.maven.lifecycle.LifecyclePhaseNotFoundException;
@@ -103,34 +104,35 @@ public class BuilderCommon
             final Set<Plugin> unsafePlugins = executionPlan.getNonThreadSafePlugins();
             if ( !unsafePlugins.isEmpty() )
             {
-                logger.warn( "*****************************************************************" );
+                for ( String s : MultilineMessageHelper.format(
-                logger.warn( "* Your build is requesting parallel execution, but project      *" );
+                        "Your build is requesting parallel execution, but this project contains the following "
-                logger.warn( "* contains the following plugin(s) that have goals not marked   *" );
+                                + "plugin(s) that have goals not marked as thread-safe to support parallel execution.",
-                logger.warn( "* as @threadSafe to support parallel building.                  *" );
+                        "While this /may/ work fine, please look for plugin updates and/or "
-                logger.warn( "* While this /may/ work fine, please look for plugin updates    *" );
+                                + "request plugins be made thread-safe.",
-                logger.warn( "* and/or request plugins be made thread-safe.                   *" );
+                        "If reporting an issue, report it against the plugin in question, not against Apache Maven." ) )
-                logger.warn( "* If reporting an issue, report it against the plugin in        *" );
+                {
-                logger.warn( "* question, not against maven-core                              *" );
+                    logger.warn( s );
-                logger.warn( "*****************************************************************" );
+                }
                 if ( logger.isDebugEnabled() )
                 {
                     final Set<MojoDescriptor> unsafeGoals = executionPlan.getNonThreadSafeMojos();
-                    logger.warn( "The following goals are not marked @threadSafe in " + project.getName() + ":" );
+                    logger.warn( "The following goals are not marked as thread-safe in " + project.getName() + ":" );
                     for ( MojoDescriptor unsafeGoal : unsafeGoals )
                     {
-                        logger.warn( unsafeGoal.getId() );
+                        logger.warn( "  " + unsafeGoal.getId() );
                     }
                 }
                 else
                 {
-                    logger.warn( "The following plugins are not marked @threadSafe in " + project.getName() + ":" );
+                    logger.warn( "The following plugins are not marked as thread-safe in " + project.getName() + ":" );
                     for ( Plugin unsafePlugin : unsafePlugins )
                     {
-                        logger.warn( unsafePlugin.getId() );
+                        logger.warn( "  " + unsafePlugin.getId() );
                     }
-                    logger.warn( "Enable debug to see more precisely which goals are not marked @threadSafe." );
+                    logger.warn( "" );
+                    logger.warn( "Enable debug to see precisely which goals are not marked as thread-safe." );
                 }
-                logger.warn( "*****************************************************************" );
+                logger.warn( MultilineMessageHelper.separatorLine() );
             }
         }
 

maven-core/src/test/java/org/apache/maven/internal/MultilineMessageHelperTest.java

@@ -0,0 +1,71 @@
+package org.apache.maven.internal;
+
+/*
+ * 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 java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class MultilineMessageHelperTest
+{
+
+    @Test
+    public void testBuilderCommon()
+    {
+        List<String> msgs = new ArrayList<>();
+        msgs.add( "*****************************************************************" );
+        msgs.add( "* Your build is requesting parallel execution, but project      *" );
+        msgs.add( "* contains the following plugin(s) that have goals not marked   *" );
+        msgs.add( "* as @threadSafe to support parallel building.                  *" );
+        msgs.add( "* While this /may/ work fine, please look for plugin updates    *" );
+        msgs.add( "* and/or request plugins be made thread-safe.                   *" );
+        msgs.add( "* If reporting an issue, report it against the plugin in        *" );
+        msgs.add( "* question, not against maven-core                              *" );
+        msgs.add( "*****************************************************************" );
+
+        assertEquals( msgs, MultilineMessageHelper.format(
+                "Your build is requesting parallel execution, but project contains the following "
+                        + "plugin(s) that have goals not marked as @threadSafe to support parallel building.",
+                "While this /may/ work fine, please look for plugin updates and/or "
+                        + "request plugins be made thread-safe.",
+                "If reporting an issue, report it against the plugin in question, not against maven-core"
+        ) );
+    }
+
+    @Test
+    public void testMojoExecutor()
+    {
+        List<String> msgs = new ArrayList<>();
+        msgs.add( "*****************************************************************" );
+        msgs.add( "* An aggregator Mojo is already executing in parallel build,    *" );
+        msgs.add( "* but aggregator Mojos require exclusive access to reactor to   *" );
+        msgs.add( "* prevent race conditions. This mojo execution will be blocked  *" );
+        msgs.add( "* until the aggregator work is done.                            *" );
+        msgs.add( "*****************************************************************" );
+
+        assertEquals( msgs, MultilineMessageHelper.format(
+                "An aggregator Mojo is already executing in parallel build, but aggregator "
+                        + "Mojos require exclusive access to reactor to prevent race conditions. This "
+                        + "mojo execution will be blocked until the aggregator work is done." ) );
+    }
+}