Fix issue #31

build.gradle

@@ -82,6 +82,7 @@ dependencies {
 	compile "org.eclipse.jgit:org.eclipse.jgit:${VER_JGIT}"
 	testCompile "junit:junit:${VER_JUNIT}"
 	testCompile "org.assertj:assertj-core:${VER_ASSERTJ}"
+	testCompile "com.diffplug.durian:durian-testlib:${VER_DURIAN}"
 
 	// add the eclipse jars to the embedded configuration
 	eclipseDeps.each { embeddedJars "p2:${it}:+" }

src/main/java/com/diffplug/gradle/spotless/ApplyFormatTask.java

@@ -0,0 +1,40 @@
+/*
+ * 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.gradle.spotless;
+
+import java.io.File;
+import java.io.IOException;
+
+public class ApplyFormatTask extends BaseFormatTask {
+	@Override
+	public void doTask(Formatter formatter) throws Exception {
+		formatApply(formatter);
+	}
+
+	/** Applies the format. */
+	private void formatApply(Formatter formatter) throws IOException {
+		for (File file : target) {
+			getLogger().debug("Applying format to " + file);
+			// keep track of the problem toFormat
+			if (paddedCell) {
+				PaddedCellTaskMisc.apply(this, formatter, file);
+			} else {
+				formatter.applyFormat(file);
+			}
+		}
+		;
+	}
+}

src/main/java/com/diffplug/gradle/spotless/BaseFormatTask.java

@@ -0,0 +1,63 @@
+/*
+ * 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.gradle.spotless;
+
+import java.io.File;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.GradleException;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.InputFiles;
+import org.gradle.api.tasks.SkipWhenEmpty;
+import org.gradle.api.tasks.TaskAction;
+
+public abstract class BaseFormatTask extends DefaultTask {
+	// set by SpotlessExtension, but possibly overridden by FormatExtension
+	@Input
+	public Charset encoding = StandardCharsets.UTF_8;
+	@Input
+	public LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX_POLICY;
+	// set by FormatExtension
+	@Input
+	public boolean paddedCell = false;
+	@InputFiles
+	@SkipWhenEmpty
+	public Iterable<File> target;
+	@Input
+	public List<FormatterStep> steps = new ArrayList<>();
+
+	@TaskAction
+	public void run() throws Exception {
+		if (target == null) {
+			throw new GradleException("You must specify 'Iterable<File> toFormat'");
+		}
+		// combine them into the master formatter
+		Formatter formatter = Formatter.builder()
+				.lineEndingsPolicy(lineEndingsPolicy)
+				.encoding(encoding)
+				.projectDirectory(getProject().getProjectDir().toPath())
+				.steps(steps)
+				.build();
+
+		doTask(formatter);
+	}
+
+	public abstract void doTask(Formatter formatter) throws Exception;
+}

src/main/java/com/diffplug/gradle/spotless/FormatTask.java → src/main/java/com/diffplug/gradle/spotless/CheckFormatTask.java

@@ -17,55 +17,17 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
+import java.io.UncheckedIOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 
-import org.gradle.api.DefaultTask;
 import org.gradle.api.GradleException;
-import org.gradle.api.tasks.TaskAction;
 
-public class FormatTask extends DefaultTask {
-	// set by SpotlessExtension, but possibly overridden by FormatExtension
-	public Charset encoding = StandardCharsets.UTF_8;
-	public LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX_POLICY;
-	// set by FormatExtension
-	public boolean paddedCell = false;
-	public Iterable<File> target;
-	public List<FormatterStep> steps = new ArrayList<>();
-	// set by plugin
-	public boolean check = false;
-
-	/** Returns the name of this format. */
-	public String getFormatName() {
-		String name = getName();
-		if (name.startsWith(SpotlessPlugin.EXTENSION)) {
-			String after = name.substring(SpotlessPlugin.EXTENSION.length());
-			if (after.endsWith(SpotlessPlugin.CHECK)) {
-				return after.substring(0, after.length() - SpotlessPlugin.CHECK.length()).toLowerCase(Locale.US);
-			} else if (after.endsWith(SpotlessPlugin.APPLY)) {
-				return after.substring(0, after.length() - SpotlessPlugin.APPLY.length()).toLowerCase(Locale.US);
-			}
-		}
-		return name;
-	}
-
-	@TaskAction
-	public void format() throws Exception {
-		if (target == null) {
-			throw new GradleException("You must specify 'Iterable<File> toFormat'");
-		}
-		// combine them into the master formatter
-		Formatter formatter = new Formatter(lineEndingsPolicy, encoding, getProject().getProjectDir().toPath(), steps);
-
-		// perform the check
-		if (check) {
-			formatCheck(formatter);
-		} else {
-			formatApply(formatter);
-		}
+public class CheckFormatTask extends BaseFormatTask {
+	@Override
+	public void doTask(Formatter formatter) throws Exception {
+		formatCheck(formatter);
 	}
 
 	/** Checks the format. */
@@ -75,8 +37,12 @@ private void formatCheck(Formatter formatter) throws IOException {
 		for (File file : target) {
 			getLogger().debug("Checking format on " + file);
 			// keep track of the problem toFormat
-			if (!formatter.isClean(file)) {
-				problemFiles.add(file);
+			try {
+				if (!formatter.isClean(file)) {
+					problemFiles.add(file);
+				}
+			} catch (IOException e) {
+				throw new UncheckedIOException(e);
 			}
 		}
 
@@ -99,16 +65,13 @@ GradleException formatViolationsFor(Formatter formatter, List<File> problemFiles
 		return new GradleException(DiffMessageFormatter.messageFor(this, formatter, problemFiles));
 	}
 
-	/** Applies the format. */
-	private void formatApply(Formatter formatter) throws IOException {
-		for (File file : target) {
-			getLogger().debug("Applying format to " + file);
-			// keep track of the problem toFormat
-			if (paddedCell) {
-				PaddedCellTaskMisc.apply(this, formatter, file);
-			} else {
-				formatter.applyFormat(file);
-			}
+	/** Returns the name of this format. */
+	String getFormatName() {
+		String name = getName();
+		if (name.startsWith(SpotlessPlugin.EXTENSION)) {
+			String after = name.substring(SpotlessPlugin.EXTENSION.length());
+			return after.substring(0, after.length() - SpotlessPlugin.CHECK.length()).toLowerCase(Locale.US);
 		}
+		return name;
 	}
 }

src/main/java/com/diffplug/gradle/spotless/DiffMessageFormatter.java

@@ -39,7 +39,7 @@ final class DiffMessageFormatter {
 	private static final int MAX_CHECK_MESSAGE_LINES = 50;
 	static final int MAX_FILES_TO_LIST = 10;
 
-	static String messageFor(FormatTask task, Formatter formatter, List<File> problemFiles) throws IOException {
+	static String messageFor(CheckFormatTask task, Formatter formatter, List<File> problemFiles) throws IOException {
 		DiffMessageFormatter diffFormater = new DiffMessageFormatter(task, formatter, problemFiles);
 		return "The following files had format violations:\n"
 				+ diffFormater.buffer
@@ -49,10 +49,10 @@ static String messageFor(FormatTask task, Formatter formatter, List<File> proble
 				+ "' to fix these violations.";
 	}
 
-	StringBuilder buffer = new StringBuilder(MAX_CHECK_MESSAGE_LINES * 64);
-	int numLines = 0;
+	private final StringBuilder buffer = new StringBuilder(MAX_CHECK_MESSAGE_LINES * 64);
+	private int numLines = 0;
 
-	private DiffMessageFormatter(FormatTask task, Formatter formatter, List<File> problemFiles) throws IOException {
+	private DiffMessageFormatter(CheckFormatTask task, Formatter formatter, List<File> problemFiles) throws IOException {
 		Preconditions.checkArgument(!problemFiles.isEmpty(), "Problem files must not be empty");
 
 		Path rootDir = task.getProject().getRootDir().toPath();
@@ -119,7 +119,7 @@ private void addLine(String line) {
 	 * look like if formatted using the given formatter. Does not end with any newline
 	 * sequence (\n, \r, \r\n).
 	 */
-	private static String diff(FormatTask task, Formatter formatter, File file) throws IOException {
+	private static String diff(CheckFormatTask task, Formatter formatter, File file) throws IOException {
 		String raw = new String(Files.readAllBytes(file.toPath()), formatter.encoding);
 		String rawUnix = LineEnding.toUnix(raw);
 		String formattedUnix;

src/main/java/com/diffplug/gradle/spotless/FilterByFileFormatterStep.java

@@ -0,0 +1,64 @@
+/*
+ * 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.gradle.spotless;
+
+import java.io.File;
+import java.util.Objects;
+import java.util.function.Predicate;
+
+final class FilterByFileFormatterStep implements FormatterStep {
+	private final FormatterStep delegateStep;
+	private final Predicate<File> filter;
+
+	FilterByFileFormatterStep(FormatterStep delegateStep, Predicate<File> filter) {
+		this.delegateStep = delegateStep;
+		this.filter = filter;
+	}
+
+	@Override
+	public String getName() {
+		return delegateStep.getName();
+	}
+
+	@Override
+	public String format(String raw, File file) throws Throwable {
+		if (filter.test(file)) {
+			return delegateStep.format(raw, file);
+		} else {
+			return raw;
+		}
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (o == null || getClass() != o.getClass()) {
+			return false;
+		}
+		FilterByFileFormatterStep that = (FilterByFileFormatterStep) o;
+		return Objects.equals(delegateStep, that.delegateStep) &&
+				Objects.equals(filter, that.filter);
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(delegateStep, filter);
+	}
+
+	private static final long serialVersionUID = 1L;
+}