Refactored to strategies for supporting AdoptOpenJDK in build.

As part of processing#5750, added support for AdoptOpenJDK (also required for

 - OracleDownloadUrlGenerator
 - AdoptOpenJdkDownloadUrlGenerator

which support Downloader. Tests and documentation included
(required refactor of build.xml).

build/jre/build.xml

@@ -1,20 +1,58 @@
 <project name="downloader" default="dist">
 
-  <target name="compile">
+  <path id="classpath.base">
+    <!-- kinda gross, but if not using the JDT, this just ignored anyway -->
+    <pathelement location="${jdt.jar};" />
+    <pathelement location="${java.mode}/jdtCompilerAdapter.jar" />
+  </path>
+
+  <path id="classpath.test">
+    <pathelement location="library-test/junit-4.8.1.jar" />
+    <pathelement location = "build" />
+    <path refid="classpath.base" />
+  </path>
+
+  <target name="test-compile">
+    <mkdir dir="build" />
+
+    <!-- Where can I expect to find Java Mode JARs? -->
+    <property name="java.mode" value="../../java/mode/" />
+
+    <javac source="1.8"
+        target="1.8"
+        srcdir="src; test"
+        destdir="build"
+        debug="true"
+        includeantruntime="true"
+        nowarn="true">
+      <classpath refid="classpath.test"/>
+    </javac>
+
+  </target>
+
+  <target name="test" depends="test-compile">
+    <junit haltonfailure="true">
+      <classpath refid="classpath.test" />
+      <formatter type="brief" usefile="false" />
+      <test name="AdoptOpenJdkDownloadUrlGeneratorTest" />
+      <test name="OracleDownloadUrlGeneratorTest" />
+    </junit>
+  </target>
+
+  <target name="compile" depends="test">
     <mkdir dir="bin" />
 
     <!-- Where can I expect to find Java Mode JARs? -->
     <property name="java.mode" value="../../java/mode/" />
 
     <javac source="1.8"
-           target="1.8"
-	   srcdir="src"
-           destdir="bin"
-	   debug="true"
-	   includeantruntime="true"
-	   nowarn="true">
-      <!-- kinda gross, but if not using the JDT, this just ignored anyway -->
-      <compilerclasspath path="${jdt.jar}; ${java.mode}/jdtCompilerAdapter.jar" />
+        target="1.8"
+        srcdir="src"
+        destdir="bin"
+        debug="true"
+        includeantruntime="true"
+        nowarn="true">
+      <classpath refid="classpath.test"/>
     </javac>
   </target>
 
@@ -32,6 +70,7 @@
 
   <target name="clean">
     <delete dir="bin" />
+    <delete dir="build" />
     <delete file="downloader.jar" />
   </target>
 

build/jre/src/AdoptOpenJdkDownloadUrlGenerator.java

@@ -1,38 +1,81 @@
+/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */
+
+/*
+  Part of the Processing project - http://processing.org
+
+  Copyright (c) 2012-19 The Processing Foundation
+  Copyright (c) 2004-12 Ben Fry and Casey Reas
+  Copyright (c) 2001-04 Massachusetts Institute of Technology
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License
+  version 2, as published by the Free Software Foundation.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software Foundation,
+  Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
 /**
- * Utility to generate
+ * Utility to generate download URLs from AdoptOpenJDK.
  */
 public class AdoptOpenJdkDownloadUrlGenerator extends DownloadUrlGenerator {
 
-    // "https://github.com/AdoptOpenJDK/openjdk11-binaries/releases/download/jdk-11.0.1%2B13/OpenJDK11U-jdk_aarch64_linux_hotspot_11.0.1_13.tar.gz";
-    private static final String BASE_URL = "https://github.com/AdoptOpenJDK/openjdk%d-binaries/releases/download/jdk-%d.%d.%d%2B%d/OpenJDK%dU-%s_%d.%d.%d_%d.tar.gz";
+    private static final String BASE_URL = "https://github.com/AdoptOpenJDK/openjdk%d-binaries/releases/download/jdk-%d.%d.%d%%2B%d/OpenJDK%dU-%s_%d.%d.%d_%d.%s";
 
     @Override
     public String buildUrl(String platform, boolean jdk, int train, int version, int update, int build, String flavor, String hash) {
         String filename = buildDownloadRemoteFilename(platform);
+        String fileExtension = buildFileExtension(platform);
         return String.format(
                 BASE_URL,
                 train,
                 train,
                 version,
                 update,
                 build,
+                train,
                 filename,
                 train,
                 version,
                 update,
-                build
+                build,
+                fileExtension
         );
     }
 
+    /**
+     * Build a the filename (the "flavor") that is expected on AdoptOpenJDK.
+     *
+     * @param downloadPlatform The platform for which the download URL is being generated like
+     *      "macos" or "linux64".
+     * @return The artifact name without extension like "jdk_x64_mac_hotspot".
+     */
     private String buildDownloadRemoteFilename(String downloadPlatform) {
         switch (downloadPlatform.toLowerCase()) {
             case "windows32": return "jdk_x86-32_windows_hotspot";
             case "windows64": return "jdk_x64_windows_hotspot";
             case "macos": return "jdk_x64_mac_hotspot";
-            case "linux32": throw new RuntimeException("Linux 32bit no longer supported by AdoptOpenJDK.");
+            case "linux32": throw new RuntimeException("Linux32 not supported by AdoptOpenJDK.");
             case "linux64": return "jdk_x64_linux_hotspot";
             case "linuxArm": return "jdk_aarch64_linux_hotspot";
             default: throw new RuntimeException("Unknown platform: " + downloadPlatform);
         }
     }
+
+    /**
+     * Determine the download file extension.
+     *
+     * @param downloadPlatform The platform for which the download URL is being generated like
+     *      "macos" or "linux64".
+     * @return The file extension without leading period like "zip" or "tar.gz".
+     */
+    private String buildFileExtension(String downloadPlatform) {
+        return downloadPlatform.startsWith("windows") ? "zip" : "tar.gz";
+    }
 }

build/jre/src/DownloadUrlGenerator.java

@@ -1,13 +1,41 @@
 /**
- * Interface for strategy to generate download URLs.
+ * Abstract base class for strategy to generate download URLs.
  */
 public abstract class DownloadUrlGenerator {
 
-    public abstract String buildUrl(String platform, boolean jdk, int train, int version, int update, int build,
-        String flavor, String hash);
+    /**
+     * Determine the URL at which the artifact can be downloaded.
+     *
+     * @param downloadPlatform The platform for which the download URL is being generated like
+     *      "macos" or "linux64".
+     * @param jdk Flag indicating if the JDK or JRE is being downloaded. True indicates that the
+     *      JDK is being downloaded and false indicates JRE.
+     * @param train The JDK train (like 1 or 11).
+     * @param version The JDK version (like 8 or 1).
+     * @param update The update (like 13).
+     * @param build The build number (like 133).
+     * @param flavor The flavor like "macosx-x64.dmg".
+     * @param hash The hash like "d54c1d3a095b4ff2b6607d096fa80163".
+     */
+    public abstract String buildUrl(String platform, boolean jdk, int train, int version,
+        int update, int build, String flavor, String hash);
 
-    public String getLocalFilename(String platform, boolean jdk, int train, int version, int update, int build,
-        String flavor, String hash) {
+    /**
+     * Determine the name of the file to which the remote file should be saved.
+     *
+     * @param downloadPlatform The platform for which the download URL is being generated like
+     *      "macos" or "linux64".
+     * @param jdk Flag indicating if the JDK or JRE is being downloaded. True indicates that the
+     *      JDK is being downloaded and false indicates JRE.
+     * @param train The JDK train (like 1 or 11).
+     * @param version The JDK version (like 8 or 1).
+     * @param update The update (like 13).
+     * @param build The build number (like 133).
+     * @param flavor The flavor like "macosx-x64.dmg".
+     * @param hash The hash like "d54c1d3a095b4ff2b6607d096fa80163".
+     */
+    public String getLocalFilename(String downloadPlatform, boolean jdk, int train, int version,
+        int update, int build, String flavor, String hash) {
 
         String baseFilename = (jdk ? "jdk" : "jre");
 

build/jre/src/OracleDownloadUrlGenerator.java

@@ -1,11 +1,35 @@
+/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */
+
+/*
+  Part of the Processing project - http://processing.org
+
+  Copyright (c) 2012-19 The Processing Foundation
+  Copyright (c) 2004-12 Ben Fry and Casey Reas
+  Copyright (c) 2001-04 Massachusetts Institute of Technology
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License
+  version 2, as published by the Free Software Foundation.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software Foundation,
+  Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+
 /**
- * Utility to generate
+ * Utility to generate the download URL from Oracle.
  */
 public class OracleDownloadUrlGenerator extends DownloadUrlGenerator{
 
     @Override
-    public String buildUrl(String platform, boolean jdk, int train, int version, int update, int build, String flavor,
-        String hash) {
+    public String buildUrl(String platform, boolean jdk, int train, int version, int update,
+        int build, String flavor, String hash) {
 
         String filename = getLocalFilename(platform, jdk, train, version, update, build, flavor, hash);
 

build/jre/test/AdoptOpenJdkDownloadUrlGeneratorTest.java

@@ -0,0 +1,84 @@
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.Ignore;
+import static org.junit.Assert.assertEquals;
+
+public class AdoptOpenJdkDownloadUrlGeneratorTest {
+
+    private static final String EXPECTED_WIN64_URL = "https://github.com/AdoptOpenJDK/openjdk11-binaries/releases/download/jdk-11.0.1%2B13/OpenJDK11U-jdk_x64_windows_hotspot_11.0.1_13.zip";
+    private static final String EXPECTED_MAC_URL = "https://github.com/AdoptOpenJDK/openjdk11-binaries/releases/download/jdk-11.0.1%2B13/OpenJDK11U-jdk_x64_mac_hotspot_11.0.1_13.tar.gz";
+    private static final String EXPECTED_LINUX_URL = "https://github.com/AdoptOpenJDK/openjdk11-binaries/releases/download/jdk-11.0.1%2B13/OpenJDK11U-jdk_x64_linux_hotspot_11.0.1_13.tar.gz";
+
+    private static final boolean JDK = true;
+    private static final int TRAIN = 11;
+    private static final int VERSION = 0;
+    private static final int UPDATE = 1;
+    private static final int BUILD = 13;
+    private static final String FLAVOR_SUFFIX = "-x64.tar.gz";
+    private static final String HASH = "";
+
+    private AdoptOpenJdkDownloadUrlGenerator urlGenerator;
+
+    @Before
+	public void setUp() throws Exception {
+		urlGenerator = new AdoptOpenJdkDownloadUrlGenerator();
+	}
+
+    @Test
+    public void testBuildUrlWindows() {
+        String url = urlGenerator.buildUrl(
+            "windows64",
+            JDK,
+            TRAIN,
+            VERSION,
+            UPDATE,
+            BUILD,
+            "windows" + FLAVOR_SUFFIX,
+            HASH
+        );
+
+        assertEquals(
+            EXPECTED_WIN64_URL,
+            url
+        );
+    }
+
+    @Test
+    public void testBuildUrlMac() {
+        String url = urlGenerator.buildUrl(
+            "macos",
+            JDK,
+            TRAIN,
+            VERSION,
+            UPDATE,
+            BUILD,
+            "mac" + FLAVOR_SUFFIX,
+            HASH
+        );
+
+        assertEquals(
+            EXPECTED_MAC_URL,
+            url
+        );
+    }
+
+    @Test
+    public void testBuildUrlLinux() {
+        String url = urlGenerator.buildUrl(
+            "linux64",
+            JDK,
+            TRAIN,
+            VERSION,
+            UPDATE,
+            BUILD,
+            "linux64" + FLAVOR_SUFFIX,
+            HASH
+        );
+
+        assertEquals(
+            EXPECTED_LINUX_URL,
+            url
+        );
+    }
+
+}

build/jre/test/OracleDownloadUrlGeneratorTest.java

@@ -0,0 +1,36 @@
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.Ignore;
+import static org.junit.Assert.assertEquals;
+
+public class OracleDownloadUrlGeneratorTest {
+
+    private static final String EXPECTED_URL = "http://download.oracle.com/otn-pub/java/jdk/8u131-b11/d54c1d3a095b4ff2b6607d096fa80163/jdk-8u131-macosx-x64.dmg";
+
+    private OracleDownloadUrlGenerator urlGenerator;
+
+    @Before
+	public void setUp() throws Exception {
+		urlGenerator = new OracleDownloadUrlGenerator();
+	}
+
+    @Test
+    public void testBuildUrl() {
+        String url = urlGenerator.buildUrl(
+            "macos",
+            true,
+            1,
+            8,
+            131,
+            11,
+            "macosx-x64.dmg",
+            "d54c1d3a095b4ff2b6607d096fa80163"
+        );
+
+        assertEquals(
+            EXPECTED_URL,
+            url
+        );
+    }
+
+}