Switch from Maven to a Gradle build.

Author: carlosame

.gitignore

@@ -7,7 +7,6 @@
 /javadoc.xml
 *.class
 /*.jardesc
-*.jar
 *.war
 *.ear
 /local.properties
@@ -17,5 +16,9 @@
 *.iml
 *.iws
 
-# Maven
+# Gradle
+**/.gradle
 /build/
+/buildSrc/build/
+
+/CHANGES.txt

README.md

@@ -1,7 +1,102 @@
 # css4j - dom4j module
 
-Subclasses several [dom4j](https://dom4j.github.io/) classes and provides CSS functionality to it. Licence is BSD 3-clause.
+Subclasses several [dom4j](https://dom4j.github.io/) classes and provides CSS functionality to it.
 
-Has an optional dependency on [XMLPull-XPP3](https://github.com/xmlpull-xpp3/xmlpull-xpp3) which is not in Maven Central, but the artifacts can be installed with the [install-xpp3.sh](https://raw.githubusercontent.com/css4j/css4j-dist/master/install-xpp3.sh) script.
+[License](LICENSE.txt) is BSD 3-clause.
 
-Please refer to the `css4j-dist` repository for build instructions.
+See the [latest Release Notes](RELEASE_NOTES.md).
+
+## Java™ Runtime Environment requirements
+All the classes in the binary package have been compiled with a [Java compiler](https://adoptium.net/)
+set to 1.7 compiler compliance level, except the `module-info.java` file.
+
+Building the library requires JDK 11 or higher.
+
+<br/>
+
+## Build from source
+To build css4j-dom4j from the code that is currently at the Git repository, Java
+11 or later is needed, although the resulting jar files can be run with a 1.7 JRE.
+
+You can run a variety of Gradle tasks with the Gradle wrapper (on Windows shells you can omit the `./`):
+
+- `./gradlew build` (normal build)
+- `./gradlew build publishToMavenLocal` (to install in local Maven repository)
+- `./gradlew copyJars` (to copy jar files into a top-level _jar_ directory)
+- `./gradlew lineEndingConversion` (to convert line endings of top-level text files to CRLF)
+- `./gradlew publish` (to deploy to a Maven repository, as described in the `publishing.repositories.maven` block of
+[build.gradle](https://github.com/css4j/css4j-dom4j/blob/1-stable/build.gradle))
+
+<br/>
+
+## Usage from a Gradle project
+If your Gradle project depends on css4j-dom4j, you can use this project's own Maven repository in a `repositories` section of
+your build file:
+```groovy
+repositories {
+    maven {
+        url "https://css4j.github.io/maven/"
+        mavenContent {
+            releasesOnly()
+        }
+        content {
+            includeGroup 'io.sf.carte'
+            includeGroup 'io.sf.jclf'
+            includeGroup 'xmlpull'
+            includeGroup 'xpp3'
+        }
+    }
+}
+```
+please use this repository **only** for the artifact groups listed in the `includeGroup` statements.
+
+Then, in your `build.gradle` file:
+```groovy
+dependencies {
+    api "io.sf.carte:css4j-dom4j:${css4jDom4jVersion}"
+}
+```
+where `css4jDom4jVersion` would be defined in a `gradle.properties` file.
+
+<br/>
+
+## Software dependencies
+
+In case that you do not use a Gradle or Maven build (which would manage the
+dependencies according to the relevant `.module` or `.pom` files), the required
+and optional library packages are the following:
+
+### Compile-time dependencies
+
+- The [css4j](https://github.com/css4j/css4j/releases) library (and its transitive
+  dependencies); version 1.3.1 or higher (but below 2.0) is recommended.
+
+- The [css4j-agent](https://github.com/css4j/css4j-agent/releases) library;
+  version 1.3.0 or higher (but below 2.0) is recommended.
+  **It is optional at runtime.**
+
+- The [dom4j](https://github.com/dom4j/dom4j) JAR package (tested with 2.1.1).
+  Requires at least version 2.0 to compile and 2.1.1 to run the tests, but you
+  should be able to run the resulting jar file with dom4j 1.6 if you are stuck with it.
+
+- The [XPP3 Pull Parser](https://github.com/xmlpull-xpp3/xmlpull-xpp3) (which
+  can be used with this library but beware that it does not support [character
+  entities](https://dev.w3.org/html5/html-author/charref)).
+  **It is optional at runtime.**
+
+### Test dependencies
+
+- A recent version of [JUnit 4](https://junit.org/junit4/).
+
+- The `batik-css`, `batik-util`and `batik-i18n` artifacts from
+  [Apache Batik](https://xmlgraphics.apache.org/batik/).
+
+- [Jaxen](https://github.com/jaxen-xpath/jaxen), this software was tested with
+  version 1.2.0.
+
+- [SLF4J](http://www.slf4j.org/), which is a logging package.
+
+<br/>
+
+## Website
+For more information please visit https://css4j.github.io/