[MJAVADOC-592] detectJavaApiLink should also respect maven.compiler.s…

…ource property

src/it/projects/MJAVADOC-592_detectApiLink/invoker.properties

@@ -0,0 +1,17 @@
+# 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.goals=javadoc:javadoc

src/it/projects/MJAVADOC-592_detectApiLink/pom.xml

@@ -0,0 +1,54 @@
+<?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 xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.plugins.javadoc.it</groupId>
+  <artifactId>mjavadoc592</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <url>https://issues.apache.org/jira/browse/MJAVADOC-592</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>7</maven.compiler.source>
+    <maven.compiler.target>7</maven.compiler.target>
+  </properties>
+
+  <build>
+    <pluginManagement>
+      <plugins>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.1</version>
+        </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-javadoc-plugin</artifactId>
+          <version>@project.version@</version>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+  </build>
+
+</project>

src/it/projects/MJAVADOC-592_detectApiLink/src/main/java/foo/Bar.java

@@ -0,0 +1,30 @@
+package foo;
+
+/*
+ * 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.io.IOException;
+
+public class Bar {
+
+    public static void main( String[] args )
+    {
+        System.out.println( "Hello Bar" );
+    }
+}

src/it/projects/MJAVADOC-592_detectApiLink/verify.groovy

@@ -0,0 +1,21 @@
+/*
+ * 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.
+ */
+
+def options = new File(basedir,'target/site/apidocs/options')
+assert options.readLines().dropWhile{it!='-linkoffline'}.get(1).startsWith("'https://docs.oracle.com/javase/7/docs/api'")

src/main/java/org/apache/maven/plugins/javadoc/AbstractJavadocMojo.java

@@ -869,7 +869,7 @@ public abstract class AbstractJavadocMojo
      * Since <a href="https://docs.oracle.com/javase/7/docs/technotes/guides/javadoc/whatsnew-1.4.html#summary">Java
      * 1.4</a>.
      */
-    @Parameter( property = "source" )
+    @Parameter( property = "source", defaultValue = "${maven.compiler.source}" )
     private String source;
 
     /**
@@ -2317,6 +2317,20 @@ protected Map<Path, Collection<String>> getFiles( Collection<Path> sourcePaths )
         if ( StringUtils.isEmpty( subpackages ) )
         {
             Collection<String> excludedPackages = getExcludedPackages();
+
+            final boolean autoExclude;
+            if ( release != null )
+            {
+                autoExclude = JavaVersion.parse( release ).isBefore( "9" );
+            }
+            else if ( source != null )
+            {
+                autoExclude = JavaVersion.parse( source ).isBefore( "9" );
+            }
+            else
+            {
+                autoExclude = false;
+            }
 
             for ( Path sourcePath : sourcePaths )
             {
@@ -2325,8 +2339,7 @@ protected Map<Path, Collection<String>> getFiles( Collection<Path> sourcePaths )
                         sourceFileIncludes, sourceFileExcludes,
                         excludedPackages ) );
 
-                if ( source != null && JavaVersion.parse( source ).isBefore( "9" )
-                    && files.remove( "module-info.java" ) )
+                if ( autoExclude && files.remove( "module-info.java" ) )
                 {
                     getLog().debug( "Auto exclude module-info.java due to source value" );
                 }
@@ -5107,9 +5120,16 @@ private void addJavadocOptions( File javadocOutputDirectory,
 
         Map<String, JavaModuleDescriptor> allModuleDescriptors = new HashMap<>();
 
-        boolean supportModulePath = javadocRuntimeVersion.isAtLeast( "9" )
-            && ( source == null || JavaVersion.parse( source ).isAtLeast( "9" ) )
-            && ( release == null || JavaVersion.parse( release ).isAtLeast( "9" ) );
+
+        boolean supportModulePath = javadocRuntimeVersion.isAtLeast( "9" );
+        if ( release != null ) 
+        {
+            supportModulePath &= JavaVersion.parse( release ).isAtLeast( "9" );
+        }
+        else if ( source != null )
+        {
+            supportModulePath &= JavaVersion.parse( source ).isAtLeast( "9" );
+        }
 
         if ( supportModulePath )
         {
@@ -6511,6 +6531,10 @@ protected final OfflineLink getDefaultJavadocApiLink()
         {
             javaApiversion = JavaVersion.parse( release );
         }
+        else if ( source != null && !source.isEmpty() )
+        {
+            javaApiversion = JavaVersion.parse( source );
+        }
         else
         {
             final String pluginId = "org.apache.maven.plugins:maven-compiler-plugin";