Refactored Eclipse formatter configuration and step creation

CHANGES.md

@@ -7,6 +7,8 @@ You might be looking for:
 
 ### Version 1.14.0-SNAPSHOT - TBD (javadoc [lib](https://diffplug.github.io/spotless/javadoc/spotless-lib/snapshot/) [lib-extra](https://diffplug.github.io/spotless/javadoc/spotless-lib-extra/snapshot/), [snapshot repo](https://oss.sonatype.org/content/repositories/snapshots/com/diffplug/spotless/))
 
+* Eclipse formatter versions decoupled from Spotless formatter step implementations to allow independent updates of M2 based Eclipse dependencies. ([#253](https://github.com/diffplug/spotless/pull/253))
+
 ### Version 1.13.0 - June 1st 2018 (javadoc [lib](https://diffplug.github.io/spotless/javadoc/spotless-lib/1.11.0/) [lib-extra](https://diffplug.github.io/spotless/javadoc/spotless-lib-extra/1.13.0/), artifact [lib]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib), [lib-extra]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib-extra)))
 
 * Add line and column numbers to ktlint errors. ([#251](https://github.com/diffplug/spotless/pull/251))

lib-extra/src/main/java/com/diffplug/spotless/extra/EclipseBasedStepBuilder.java

@@ -0,0 +1,163 @@
+/*
+ * Copyright 2016 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.extra;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.Serializable;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Properties;
+
+import com.diffplug.common.base.Errors;
+import com.diffplug.spotless.FileSignature;
+import com.diffplug.spotless.FormatterFunc;
+import com.diffplug.spotless.FormatterProperties;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.JarState;
+import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.ThrowingEx;
+
+/**
+ * Generic Eclipse based formatter step {@link State} builder.
+ */
+public class EclipseBasedStepBuilder {
+	private final String formatterName;
+	private final ThrowingEx.Function<State, FormatterFunc> stateToFormatter;
+	private final Provisioner jarProvisioner;
+
+	/**
+	 * Resource location of Spotless Eclipse Formatter Maven coordinate lists.
+	 * <p>
+	 * Spotless Eclipse Formatter dependencies have fixed transitive versions, since Spotless Eclipse Formatter
+	 * implementations access internal methods of the Eclipse plugins, which may change with every
+	 * version change, including minor and patch version changes.
+	 * At the resource location for each supported Spotless Eclipse Formatter, a text file is provided, containing
+	 * the fixed versions for the formatter and its transitive dependencies.
+	 * Each line is either a comment starting with {@code #} or corresponds to the format
+	 * {@code <groupId>:<artifactId>[:packaging][:classifier]:<versionRestriction>}
+	 * </p>
+	 */
+	private static final String ECLIPSE_FORMATTER_RESOURCES = EclipseBasedStepBuilder.class.getPackage().getName().replace('.', '/');
+
+	private List<String> dependencies = new ArrayList<>();
+	private Iterable<File> settingsFiles = new ArrayList<>();
+
+	/** Initialize valid default configuration, taking latest version */
+	public EclipseBasedStepBuilder(String formatterName, Provisioner jarProvisioner, ThrowingEx.Function<State, FormatterFunc> stateToFormatter) {
+		this.formatterName = Objects.requireNonNull(formatterName, "formatterName");
+		this.jarProvisioner = Objects.requireNonNull(jarProvisioner, "jarProvisioner");
+		this.stateToFormatter = Objects.requireNonNull(stateToFormatter, "stateToFormatter");
+	}
+
+	/** Returns the FormatterStep (whose state will be calculated lazily). */
+	public FormatterStep build() {
+		return FormatterStep.createLazy(formatterName, this::get, stateToFormatter);
+	}
+
+	/** Set dependencies for the corresponding Eclipse version */
+	public void setVersion(String version) {
+		String url = "/" + ECLIPSE_FORMATTER_RESOURCES + "/" + formatterName.replace(' ', '_') + "/v" + version + ".lockfile";
+		InputStream depsFile = EclipseBasedStepBuilder.class.getResourceAsStream(url);
+		if (depsFile == null) {
+			throw new IllegalArgumentException("No such version " + version + ", expected at " + url);
+		}
+		byte[] content = toByteArray(depsFile);
+		String allLines = new String(content, StandardCharsets.UTF_8);
+		String[] lines = allLines.split("\n");
+		dependencies.clear();
+		for (String line : lines) {
+			if (!line.startsWith("#")) {
+				dependencies.add(line);
+			}
+		}
+	}
+
+	private static byte[] toByteArray(InputStream in) {
+		ByteArrayOutputStream to = new ByteArrayOutputStream();
+		byte[] buf = new byte[8192];
+		try {
+			while (true) {
+				int r = in.read(buf);
+				if (r == -1) {
+					break;
+				}
+				to.write(buf, 0, r);
+			}
+			return to.toByteArray();
+		} catch (IOException e) {
+			throw Errors.asRuntime(e);
+		}
+	}
+
+	/** Set settings files containing Eclipse preferences */
+	public void setPreferences(Iterable<File> settingsFiles) {
+		this.settingsFiles = settingsFiles;
+	}
+
+	/** Creates the state of the configuration. */
+	EclipseBasedStepBuilder.State get() throws IOException {
+		/*
+		 * The current use case is tailored for Gradle.
+		 * Gradle calls this method only once per execution
+		 * and compares the State with the one of a previous run
+		 * for incremental building.
+		 * Hence a lazy construction is not required.
+		 */
+		return new State(
+				jarProvisioner,
+				dependencies,
+				settingsFiles);
+	}
+
+	/**
+	 * State of Eclipse configuration items, providing functionality to derived information
+	 * based on the state.
+	 */
+	public static class State implements Serializable {
+		// Not used, only the serialization output is required to determine whether the object has changed
+		private static final long serialVersionUID = 1L;
+
+		private final JarState jarState;
+		private final FileSignature settingsFiles;
+
+		/** State constructor expects that all passed items are not modified afterwards */
+		protected State(Provisioner jarProvisioner, List<String> dependencies, Iterable<File> settingsFiles) throws IOException {
+			this.jarState = JarState.from(dependencies, jarProvisioner);
+			this.settingsFiles = FileSignature.signAsList(settingsFiles);
+		}
+
+		/** Get formatter preferences */
+		public Properties getPreferences() {
+			//Keep the IllegalArgumentException since it contains detailed information
+			FormatterProperties preferences = FormatterProperties.from(settingsFiles.files());
+			return preferences.getProperties();
+		}
+
+		/** Load class based on the given configuration of JAR provider and Maven coordinates. */
+		public Class<?> loadClass(String name) {
+			try {
+				return jarState.getClassLoader().loadClass(name);
+			} catch (ClassNotFoundException e) {
+				throw Errors.asRuntime(e);
+			}
+		}
+	}
+}

lib-extra/src/main/java/com/diffplug/spotless/extra/config/package-info.java

@@ -0,0 +1,7 @@
+@ParametersAreNonnullByDefault
+@ReturnValuesAreNonnullByDefault
+package com.diffplug.spotless.extra.config;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+
+import com.diffplug.spotless.annotations.ReturnValuesAreNonnullByDefault;

lib-extra/src/main/java/com/diffplug/spotless/extra/groovy/GrEclipseFormatterStep.java

@@ -16,76 +16,62 @@
 package com.diffplug.spotless.extra.groovy;
 
 import java.io.File;
-import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.util.Objects;
 import java.util.Properties;
 
-import com.diffplug.spotless.FileSignature;
 import com.diffplug.spotless.FormatterFunc;
-import com.diffplug.spotless.FormatterProperties;
 import com.diffplug.spotless.FormatterStep;
-import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.extra.EclipseBasedStepBuilder;
 
 /** Formatter step which calls out to the Groovy-Eclipse formatter. */
-public class GrEclipseFormatterStep {
-	private static final String NAME = "groovy-eclipse formatter";
+public final class GrEclipseFormatterStep {
+	// prevent direct instantiation
+	private GrEclipseFormatterStep() {}
+
+	private static final String NAME = "groovy eclipse formatter";
 	private static final String FORMATTER_CLASS = "com.diffplug.gradle.spotless.groovy.eclipse.GrEclipseFormatterStepImpl";
-	private static final String DEFAULT_VERSION = "2.3.0";
-	private static final String MAVEN_COORDINATE = "com.diffplug.spotless:spotless-ext-greclipse:";
+	private static final String DEFAULT_VERSION = "4.6.3";
 	private static final String FORMATTER_METHOD = "format";
 
 	/** Creates a formatter step using the default version for the given settings file. */
+	@Deprecated
 	public static FormatterStep create(Iterable<File> settingsFiles, Provisioner provisioner) {
 		return create(defaultVersion(), settingsFiles, provisioner);
 	}
 
 	/** Creates a formatter step for the given version and settings file. */
+	@Deprecated
 	public static FormatterStep create(String version, Iterable<File> settingsFiles, Provisioner provisioner) {
-		return FormatterStep.createLazy(
-				NAME,
-				() -> new State(JarState.from(MAVEN_COORDINATE + version, provisioner), settingsFiles),
-				State::createFormat);
+		EclipseBasedStepBuilder builder = createBuilder(provisioner);
+		builder.setVersion(version);
+		builder.setPreferences(settingsFiles);
+		return builder.build();
 	}
 
 	public static String defaultVersion() {
 		return DEFAULT_VERSION;
 	}
 
-	private static class State implements Serializable {
-		private static final long serialVersionUID = 1L;
-
-		/** The jar that contains the eclipse formatter. */
-		final JarState jarState;
-		/** The signature of the settings file. */
-		final FileSignature settings;
-
-		State(JarState jar, final Iterable<File> settingsFiles) throws Exception {
-			this.jarState = Objects.requireNonNull(jar);
-			this.settings = FileSignature.signAsList(settingsFiles);
-		}
-
-		FormatterFunc createFormat() throws Exception {
-			FormatterProperties preferences = FormatterProperties.from(settings.files());
-
-			ClassLoader classLoader = jarState.getClassLoader();
+	/** Provides default configuration */
+	public static EclipseBasedStepBuilder createBuilder(Provisioner provisioner) {
+		return new EclipseBasedStepBuilder(NAME, provisioner, GrEclipseFormatterStep::apply);
+	}
 
-			// instantiate the formatter and get its format method
-			Class<?> formatterClazz = classLoader.loadClass(FORMATTER_CLASS);
-			Object formatter = formatterClazz.getConstructor(Properties.class).newInstance(preferences.getProperties());
-			Method method = formatterClazz.getMethod(FORMATTER_METHOD, String.class);
-			return input -> {
-				try {
-					return (String) method.invoke(formatter, input);
-				} catch (InvocationTargetException exceptionWrapper) {
-					Throwable throwable = exceptionWrapper.getTargetException();
-					Exception exception = (throwable instanceof Exception) ? (Exception) throwable : null;
-					throw (null == exception) ? exceptionWrapper : exception;
-				}
-			};
-		}
+	private static FormatterFunc apply(EclipseBasedStepBuilder.State state) throws Exception {
+		Class<?> formatterClazz = state.loadClass(FORMATTER_CLASS);
+		Object formatter = formatterClazz.getConstructor(Properties.class).newInstance(state.getPreferences());
+		Method method = formatterClazz.getMethod(FORMATTER_METHOD, String.class);
+		return input -> {
+			try {
+				return (String) method.invoke(formatter, input);
+			} catch (InvocationTargetException exceptionWrapper) {
+				Throwable throwable = exceptionWrapper.getTargetException();
+				Exception exception = (throwable instanceof Exception) ? (Exception) throwable : null;
+				throw (null == exception) ? exceptionWrapper : exception;
+			}
+		};
 	}
 
 }

lib-extra/src/main/java/com/diffplug/spotless/extra/java/EclipseFormatterStep.java

@@ -16,29 +16,23 @@
 package com.diffplug.spotless.extra.java;
 
 import java.io.File;
-import java.io.Serializable;
-import java.lang.reflect.Method;
 import java.util.Collections;
 import java.util.Objects;
-import java.util.Properties;
 
-import com.diffplug.spotless.FileSignature;
-import com.diffplug.spotless.FormatterFunc;
-import com.diffplug.spotless.FormatterProperties;
 import com.diffplug.spotless.FormatterStep;
-import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.extra.EclipseBasedStepBuilder;
 
-/** Formatter step which calls out to the Eclipse formatter. */
+/**
+ * Formatter step which calls out to the Eclipse formatter.
+ * This class is deprecated. Use {@link EclipseJdtFormatterStep} instead.
+ */
+@Deprecated
 public final class EclipseFormatterStep {
 	// prevent direct instantiation
 	private EclipseFormatterStep() {}
 
 	private static final String DEFAULT_VERSION = "4.7.2";
-	private static final String NAME = "eclipse formatter";
-	private static final String MAVEN_COORDINATE = "com.diffplug.spotless:spotless-ext-eclipse-jdt:";
-	private static final String FORMATTER_CLASS = "com.diffplug.gradle.spotless.java.eclipse.EclipseFormatterStepImpl";
-	private static final String FORMATTER_METHOD = "format";
 
 	/** Creates a formatter step for the given version and settings file.
 	 * Formatter steps based on property configuration should support zero (default configuration)
@@ -66,39 +60,14 @@ public static FormatterStep create(String version, Iterable<File> settingsFiles,
 		Objects.requireNonNull(version, "version");
 		Objects.requireNonNull(settingsFiles, "settingsFiles");
 		Objects.requireNonNull(provisioner, "provisioner");
-		return FormatterStep.createLazy(NAME,
-				() -> new State(JarState.from(MAVEN_COORDINATE + version, provisioner), settingsFiles),
-				State::createFormat);
+		EclipseBasedStepBuilder builder = EclipseJdtFormatterStep.createBuilder(provisioner);
+		builder.setPreferences(settingsFiles);
+		builder.setVersion(DEFAULT_VERSION);
+		return builder.build();
 	}
 
 	public static String defaultVersion() {
 		return DEFAULT_VERSION;
 	}
 
-	private static class State implements Serializable {
-		private static final long serialVersionUID = 1L;
-
-		/** The jar that contains the eclipse formatter. */
-		final JarState jarState;
-		/** The signature of the settings file. */
-		final FileSignature settings;
-
-		State(JarState jar, final Iterable<File> settingsFiles) throws Exception {
-			this.jarState = jar;
-			this.settings = FileSignature.signAsList(settingsFiles);
-		}
-
-		FormatterFunc createFormat() throws Exception {
-			FormatterProperties preferences = FormatterProperties.from(settings.files());
-
-			ClassLoader classLoader = jarState.getClassLoader();
-
-			// instantiate the formatter and get its format method
-			Class<?> formatterClazz = classLoader.loadClass(FORMATTER_CLASS);
-			Object formatter = formatterClazz.getConstructor(Properties.class).newInstance(preferences.getProperties());
-			Method method = formatterClazz.getMethod(FORMATTER_METHOD, String.class);
-			return input -> (String) method.invoke(formatter, input);
-		}
-	}
-
 }