Refactor the public API of LicenseHeaderStep

CHANGES.md

@@ -18,6 +18,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * **BREAKING** `FileSignature` can no longer sign folders, only files.  Signatures are now based only on filename (not path), size, and a content hash.  It throws an error if a signature is attempted on a folder or on multiple files with different paths but the same filename - it never breaks silently.  This change does not break any of Spotless' internal logic, so it is unlikely to affect any of Spotless' consumers either. ([#571](https://github.com/diffplug/spotless/pull/571))
   * This change allows the maven plugin to cache classloaders across subprojects when loading config resources from the classpath (fixes [#559](https://github.com/diffplug/spotless/issues/559)).
   * This change also allows the gradle plugin to work with the remote buildcache (fixes [#280](https://github.com/diffplug/spotless/issues/280)).
+* **BREAKING** Heavy refactor of the `LicenseHeaderStep` public API.  Doesn't change internal behavior, but makes implementation of the gradle and maven plugins much easier. ([#628](https://github.com/diffplug/spotless/pull/628))
 
 ## [1.34.1] - 2020-06-17
 ### Changed

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java

@@ -18,7 +18,6 @@
 import static com.diffplug.gradle.spotless.PluginGradlePreconditions.requireElementsNonNull;
 
 import java.io.File;
-import java.io.IOException;
 import java.io.Serializable;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
@@ -47,6 +46,7 @@
 import com.diffplug.spotless.generic.EndWithNewlineStep;
 import com.diffplug.spotless.generic.IndentStep;
 import com.diffplug.spotless.generic.LicenseHeaderStep;
+import com.diffplug.spotless.generic.LicenseHeaderStep.YearMode;
 import com.diffplug.spotless.generic.ReplaceRegexStep;
 import com.diffplug.spotless.generic.ReplaceStep;
 import com.diffplug.spotless.generic.TrimTrailingWhitespaceStep;
@@ -443,21 +443,20 @@ public void indentWithTabs() {
 	 * For most language-specific formats (e.g. java, scala, etc.) you can omit the second `delimiter` argument, because it is supplied
 	 * automatically ({@link HasBuiltinDelimiterForLicense}).
 	 */
-	public abstract class LicenseHeaderConfig {
-		String delimiter;
-		String yearSeparator = LicenseHeaderStep.defaultYearDelimiter();
+	public class LicenseHeaderConfig {
+		LicenseHeaderStep builder;
 		Boolean updateYearWithLatest = null;
 
-		public LicenseHeaderConfig(String delimiter) {
-			this.delimiter = Objects.requireNonNull(delimiter, "delimiter");
+		public LicenseHeaderConfig(LicenseHeaderStep builder) {
+			this.builder = builder;
 		}
 
 		/**
 		 * @param delimiter
 		 *            Spotless will look for a line that starts with this regular expression pattern to know what the "top" is.
 		 */
 		public LicenseHeaderConfig delimiter(String delimiter) {
-			this.delimiter = Objects.requireNonNull(delimiter, "delimiter");
+			builder = builder.withDelimiter(delimiter);
 			replaceStep(createStep());
 			return this;
 		}
@@ -467,7 +466,7 @@ public LicenseHeaderConfig delimiter(String delimiter) {
 		 *           The characters used to separate the first and last years in multi years patterns.
 		 */
 		public LicenseHeaderConfig yearSeparator(String yearSeparator) {
-			this.yearSeparator = Objects.requireNonNull(yearSeparator, "yearSeparator");
+			builder = builder.withYearSeparator(yearSeparator);
 			replaceStep(createStep());
 			return this;
 		}
@@ -483,61 +482,15 @@ public LicenseHeaderConfig updateYearWithLatest(boolean updateYearWithLatest) {
 			return this;
 		}
 
-		protected abstract String licenseHeader() throws IOException;
-
 		FormatterStep createStep() {
-			if ("true".equals(spotless.project.findProperty(LicenseHeaderStep.FLAG_SET_LICENSE_HEADER_YEARS_FROM_GIT_HISTORY()))) {
-				return FormatterStep.createNeverUpToDateLazy(LicenseHeaderStep.name(), () -> {
-					boolean updateYear = false; // doesn't matter
-					LicenseHeaderStep step = new LicenseHeaderStep(licenseHeader(), delimiter, yearSeparator, updateYear);
-					return new FormatterFunc() {
-						@Override
-						public String apply(String input, File source) throws Exception {
-							return step.setLicenseHeaderYearsFromGitHistory(input, source);
-						}
-
-						@Override
-						public String apply(String input) throws Exception {
-							throw new UnsupportedOperationException();
-						}
-					};
-				});
-			} else {
-				return FormatterStep.createLazy(LicenseHeaderStep.name(), () -> {
-					// by default, we should update the year if the user is using ratchetFrom
+			return builder.withYearModeLazy(() -> {
+				if ("true".equals(spotless.project.findProperty(LicenseHeaderStep.FLAG_SET_LICENSE_HEADER_YEARS_FROM_GIT_HISTORY()))) {
+					return YearMode.SET_FROM_GIT;
+				} else {
 					boolean updateYear = updateYearWithLatest == null ? getRatchetFrom() != null : updateYearWithLatest;
-					return new LicenseHeaderStep(licenseHeader(), delimiter, yearSeparator, updateYear);
-				}, step -> step::format);
-			}
-		}
-	}
-
-	private class LicenseStringHeaderConfig extends LicenseHeaderConfig {
-		private String header;
-
-		LicenseStringHeaderConfig(String delimiter, String header) {
-			super(delimiter);
-			this.header = Objects.requireNonNull(header, "header");
-		}
-
-		@Override
-		protected String licenseHeader() {
-			return header;
-		}
-	}
-
-	private class LicenseFileHeaderConfig extends LicenseHeaderConfig {
-		private Object headerFile;
-
-		LicenseFileHeaderConfig(String delimiter, Object headerFile) {
-			super(delimiter);
-			this.headerFile = Objects.requireNonNull(headerFile, "headerFile");
-		}
-
-		@Override
-		protected String licenseHeader() throws IOException {
-			byte[] content = Files.readAllBytes(getProject().file(headerFile).toPath());
-			return new String(content, getEncoding());
+					return updateYear ? YearMode.UPDATE_TO_TODAY : YearMode.PRESERVE;
+				}
+			}).build();
 		}
 	}
 
@@ -548,7 +501,7 @@ protected String licenseHeader() throws IOException {
 	 *            Spotless will look for a line that starts with this regular expression pattern to know what the "top" is.
 	 */
 	public LicenseHeaderConfig licenseHeader(String licenseHeader, String delimiter) {
-		LicenseHeaderConfig config = new LicenseStringHeaderConfig(delimiter, licenseHeader);
+		LicenseHeaderConfig config = new LicenseHeaderConfig(LicenseHeaderStep.headerDelimiter(licenseHeader, delimiter));
 		addStep(config.createStep());
 		return config;
 	}
@@ -560,7 +513,11 @@ public LicenseHeaderConfig licenseHeader(String licenseHeader, String delimiter)
 	 *            Spotless will look for a line that starts with this regular expression pattern to know what the "top" is.
 	 */
 	public LicenseHeaderConfig licenseHeaderFile(Object licenseHeaderFile, String delimiter) {
-		LicenseHeaderConfig config = new LicenseFileHeaderConfig(delimiter, licenseHeaderFile);
+		LicenseHeaderConfig config = new LicenseHeaderConfig(LicenseHeaderStep.headerDelimiter(() -> {
+			File file = getProject().file(licenseHeaderFile);
+			byte[] data = Files.readAllBytes(file.toPath());
+			return new String(data, getEncoding());
+		}, delimiter));
 		addStep(config.createStep());
 		return config;
 	}

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/LicenseHeaderTest.java

@@ -46,7 +46,7 @@ private void assertUnchanged(String year) throws IOException {
 
 	private void assertTransform(String yearBefore, String yearAfter) throws IOException {
 		setFile(TEST_JAVA).toContent("/** " + yearBefore + " */\n" + CONTENT);
-		gradleRunner().withArguments("spotlessApply", "--stacktrace").build();
+		gradleRunner().withArguments("spotlessApply", "--stacktrace").forwardOutput().build();
 		assertFile(TEST_JAVA).hasContent("/** " + yearAfter + " */\n" + CONTENT);
 	}
 

plugin-maven/src/main/java/com/diffplug/spotless/maven/generic/LicenseHeader.java

@@ -15,15 +15,14 @@
  */
 package com.diffplug.spotless.maven.generic;
 
-import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 
 import org.apache.maven.plugins.annotations.Parameter;
 
-import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.generic.LicenseHeaderStep;
+import com.diffplug.spotless.generic.LicenseHeaderStep.YearMode;
 import com.diffplug.spotless.maven.FormatterStepConfig;
 import com.diffplug.spotless.maven.FormatterStepFactory;
 
@@ -45,32 +44,17 @@ public final FormatterStep newFormatterStep(FormatterStepConfig config) {
 			throw new IllegalArgumentException("You need to specify 'delimiter'.");
 		}
 		if (file != null ^ content != null) {
-			FormatterStep unfiltered;
+			YearMode yearMode;
 			if ("true".equals(config.spotlessSetLicenseHeaderYearsFromGitHistory().orElse(""))) {
-				unfiltered = FormatterStep.createNeverUpToDateLazy(LicenseHeaderStep.name(), () -> {
-					boolean updateYear = false; // doesn't matter
-					LicenseHeaderStep step = new LicenseHeaderStep(readFileOrContent(config), delimiterString, LicenseHeaderStep.defaultYearDelimiter(), updateYear);
-					return new FormatterFunc() {
-						@Override
-						public String apply(String input, File source) throws Exception {
-							return step.setLicenseHeaderYearsFromGitHistory(input, source);
-						}
-
-						@Override
-						public String apply(String input) throws Exception {
-							throw new UnsupportedOperationException();
-						}
-					};
-				});
+				yearMode = YearMode.SET_FROM_GIT;
 			} else {
-				unfiltered = FormatterStep.createLazy(LicenseHeaderStep.name(), () -> {
-					// by default, we should update the year if the user is using ratchetFrom
-					boolean updateYear = config.getRatchetFrom().isPresent();
-					String header = readFileOrContent(config);
-					return new LicenseHeaderStep(header, delimiterString, LicenseHeaderStep.defaultYearDelimiter(), updateYear);
-				}, step -> step::format);
+				boolean updateYear = config.getRatchetFrom().isPresent();
+				yearMode = updateYear ? YearMode.UPDATE_TO_TODAY : YearMode.PRESERVE;
 			}
-			return unfiltered.filterByFile(LicenseHeaderStep.unsupportedJvmFilesFilter());
+			return LicenseHeaderStep.headerDelimiter(() -> readFileOrContent(config), delimiterString)
+					.withYearMode(yearMode)
+					.build()
+					.filterByFile(LicenseHeaderStep.unsupportedJvmFilesFilter());
 		} else {
 			throw new IllegalArgumentException("Must specify exactly one of 'file' or 'content'.");
 		}

plugin-maven/src/test/java/com/diffplug/spotless/maven/generic/LicenseHeaderRatchetTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2020 DiffPlug
+ *
+ * Licensed 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.
+ */
+package com.diffplug.spotless.maven.generic;
+
+import java.io.IOException;
+import java.time.YearMonth;
+
+import org.eclipse.jgit.api.Git;
+import org.junit.Test;
+
+import com.diffplug.spotless.maven.MavenIntegrationHarness;
+
+public class LicenseHeaderRatchetTest extends MavenIntegrationHarness {
+	private static final String NOW = String.valueOf(YearMonth.now().getYear());
+
+	private static final String TEST_JAVA = "src/main/java/pkg/Test.java";
+	private static final String CONTENT = "package pkg;\npublic class Test {}";
+
+	private void setRatchetFrom(String ratchetFrom) throws IOException {
+		writePomWithJavaSteps(
+				"<licenseHeader>",
+				"  <content>/** $YEAR */</content>",
+				"</licenseHeader>",
+				ratchetFrom);
+	}
+
+	private void assertUnchanged(String year) throws Exception {
+		assertTransform(year, year);
+	}
+
+	private void assertTransform(String yearBefore, String yearAfter) throws Exception {
+		setFile(TEST_JAVA).toContent("/** " + yearBefore + " */\n" + CONTENT);
+		mavenRunner().withArguments("spotless:apply").runNoError();
+		assertFile(TEST_JAVA).hasContent("/** " + yearAfter + " */\n" + CONTENT);
+	}
+
+	private void testSuiteUpdateWithLatest(boolean update) throws Exception {
+		if (update) {
+			assertTransform("2003", "2003-" + NOW);
+			assertTransform("2003-2005", "2003-" + NOW);
+		} else {
+			assertUnchanged("2003");
+			assertUnchanged("2003-2005");
+		}
+		assertUnchanged(NOW);
+		assertTransform("", NOW);
+	}
+
+	@Test
+	public void normal() throws Exception {
+		setRatchetFrom("");
+		testSuiteUpdateWithLatest(false);
+	}
+
+	@Test
+	public void ratchetFrom() throws Exception {
+		try (Git git = Git.init().setDirectory(rootFolder()).call()) {
+			git.commit().setMessage("First commit").call();
+		}
+		setRatchetFrom("<ratchetFrom>HEAD</ratchetFrom>");
+		testSuiteUpdateWithLatest(true);
+	}
+}

testlib/src/test/java/com/diffplug/spotless/cpp/CppDefaultsTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2020 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,7 +31,7 @@ public class CppDefaultsTest extends ResourceHarness {
 	@Test
 	public void testDelimiterExpr() throws Exception {
 		final String header = "/*My tests header*/";
-		FormatterStep step = LicenseHeaderStep.createFromHeader(header, CppDefaults.DELIMITER_EXPR);
+		FormatterStep step = LicenseHeaderStep.headerDelimiter(header, CppDefaults.DELIMITER_EXPR).build();
 		final File dummyFile = setFile("src/main/cpp/file1.dummy").toContent("");
 		for (String testSource : Arrays.asList(
 				"//Accpet multiple spaces between composed term.@using  namespace std;",

testlib/src/test/java/com/diffplug/spotless/css/CssDefaultsTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2020 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,7 +33,7 @@ public class CssDefaultsTest extends ResourceHarness {
 	@Test
 	public void testDelimiterExpr() throws Exception {
 		final String header = "/*My tests header*/";
-		FormatterStep step = LicenseHeaderStep.createFromHeader(header, CssDefaults.DELIMITER_EXPR);
+		FormatterStep step = LicenseHeaderStep.headerDelimiter(header, CssDefaults.DELIMITER_EXPR).build();
 		final File dummyFile = setFile("src/main/cpp/file1.dummy").toContent("");
 		for (String testSource : Arrays.asList(
 				"/* Starts with element selector */@\np {",