Don't set jdt compiler/compliance versions in Eclipse plugin

Remove jdt compiler/compliance version preference and update
`ProjectSettingsFiles` to keep existing values.

Closes gh-278

Author: philwebb

spring-javaformat-eclipse/io.spring.javaformat.eclipse.tests/src/io/spring/javaformat/eclipse/projectsettings/ProjectPropertiesTests.java

@@ -85,7 +85,6 @@ public void getModifiedContentReplacesCopyrightYear() throws IOException {
 		ProjectSettingsFile prefs = getFile(files, "org.eclipse.jdt.ui.prefs");
 		String content = loadContent(properties.getModifiedContent(prefs).getContent(JavaFormatConfig.DEFAULT));
 		assertThat(content).contains("Copyright " + year + " the original author or authors");
-
 	}
 
 	private ProjectSettingsFile getFile(ProjectSettingsFiles files, String name) {

spring-javaformat-eclipse/io.spring.javaformat.eclipse.tests/src/io/spring/javaformat/eclipse/projectsettings/ProjectSettingsFilesTests.java

@@ -16,8 +16,13 @@
 
 package io.spring.javaformat.eclipse.projectsettings;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.util.Collections;
 
 import org.eclipse.core.resources.IFile;
@@ -28,8 +33,11 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.will;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
@@ -51,18 +59,50 @@ public void iteratorIteratesFiles() throws Exception {
 	}
 
 	@Test
-	public void applyToProjectCopiesToDotSettings() throws Exception {
-		File prefsFile = new File(this.temp, "foo.prefs");
-		prefsFile.createNewFile();
-		ProjectSettingsFile file = ProjectSettingsFile.fromFile(prefsFile);
+	public void applyToProjectWithoutFileCopiesToDotSettings() throws Exception {
+		ProjectSettingsFile file = createPrefsFile();
+		ProjectSettingsFiles files = new ProjectSettingsFiles(Collections.singleton(file), new ProjectProperties());
+		IProject project = mock(IProject.class);
+		IProgressMonitor monitor = mock(IProgressMonitor.class);
+		IFile projectFile = mock(IFile.class);
+		given(project.getFile(".settings/foo.prefs")).willReturn(projectFile);
+		given(projectFile.exists()).willReturn(false);
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		will((invocation) -> {
+			invocation.getArgument(0, InputStream.class).transferTo(out);
+			return null;
+		}).given(projectFile).create(any(), anyBoolean(), any());
+		files.applyToProject(project, monitor);
+		verify(projectFile).create(any(), eq(true), any());
+		assertThat(out.toString(StandardCharsets.UTF_8)).isEqualTo("y=z\n");
+	}
+
+	@Test
+	public void applyToProjectWithFileMergesToDotSettings() throws Exception {
+		ProjectSettingsFile file = createPrefsFile();
 		ProjectSettingsFiles files = new ProjectSettingsFiles(Collections.singleton(file), new ProjectProperties());
 		IProject project = mock(IProject.class);
 		IProgressMonitor monitor = mock(IProgressMonitor.class);
 		IFile projectFile = mock(IFile.class);
 		given(project.getFile(".settings/foo.prefs")).willReturn(projectFile);
 		given(projectFile.exists()).willReturn(true);
+		given(projectFile.getContents(true))
+				.willReturn(new ByteArrayInputStream("a=b\n".getBytes(StandardCharsets.UTF_8)));
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		will((invocation) -> {
+			invocation.getArgument(0, InputStream.class).transferTo(out);
+			return null;
+		}).given(projectFile).setContents((InputStream) any(), anyInt(), any());
 		files.applyToProject(project, monitor);
 		verify(projectFile).setContents((InputStream) any(), eq(1), eq(monitor));
+		assertThat(out.toString(StandardCharsets.UTF_8)).isEqualTo("a=b\ny=z\n");
+	}
+
+	private ProjectSettingsFile createPrefsFile() throws IOException {
+		File prefsFile = new File(this.temp, "foo.prefs");
+		Files.copy(new ByteArrayInputStream("y=z\n".getBytes(StandardCharsets.UTF_8)), prefsFile.toPath());
+		ProjectSettingsFile file = ProjectSettingsFile.fromFile(prefsFile);
+		return file;
 	}
 
 }

spring-javaformat-eclipse/io.spring.javaformat.eclipse/src/io/spring/javaformat/eclipse/projectsettings/ProjectSettingsFiles.java

@@ -17,13 +17,22 @@
 package io.spring.javaformat.eclipse.projectsettings;
 
 import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Properties;
+import java.util.Set;
+import java.util.TreeSet;
 
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
@@ -77,12 +86,30 @@ public void applyToProject(IProject project, IProgressMonitor monitor) throws IO
 					destination.create(new BufferedInputStream(content), true, monitor);
 				}
 				else {
-					destination.setContents(new BufferedInputStream(content), IResource.FORCE, monitor);
+					Properties properties = new OrderedProperties();
+					try (InputStream existingContent = destination.getContents(true)) {
+						if (existingContent != null) {
+							properties.load(existingContent);
+						}
+					}
+					properties.load(content);
+					destination.setContents(
+							new ByteArrayInputStream(stripTimestamp(properties).getBytes(StandardCharsets.UTF_8)),
+							IResource.FORCE, monitor);
 				}
 			}
 		}
 	}
 
+	private String stripTimestamp(Properties properties) throws IOException {
+		try (ByteArrayOutputStream output = new ByteArrayOutputStream()) {
+			properties.store(output, null);
+			String string = output.toString(StandardCharsets.UTF_8);
+			String separator = System.getProperty("line.separator");
+			return string.substring(string.indexOf(separator) + separator.length());
+		}
+	}
+
 	private JavaFormatConfig getJavaFormatConfig(IProject project) {
 		try {
 			IPath location = project.getLocation();
@@ -94,4 +121,28 @@ private JavaFormatConfig getJavaFormatConfig(IProject project) {
 		}
 	}
 
+	static class OrderedProperties extends Properties {
+
+		private static final long serialVersionUID = 1L;
+
+		@Override
+		public Set<Map.Entry<Object, Object>> entrySet() {
+			Set<Map.Entry<Object, Object>> set = new TreeSet<Map.Entry<Object, Object>>(new MapEntryKeyComparator());
+			set.addAll(super.entrySet());
+			return set;
+		};
+
+	}
+
+	private static class MapEntryKeyComparator implements Comparator<Map.Entry<Object, Object>> {
+
+		@Override
+		public int compare(Entry<Object, Object> o1, Entry<Object, Object> o2) {
+			Object k1 = o1.getKey();
+			Object k2 = o2.getKey();
+			return String.valueOf(k1).compareTo(String.valueOf(k2));
+		}
+
+	}
+
 }

spring-javaformat-eclipse/io.spring.javaformat.eclipse/src/io/spring/javaformat/eclipse/projectsettings/org.eclipse.jdt.core.prefs

@@ -11,9 +11,7 @@ org.eclipse.jdt.core.codeComplete.staticFinalFieldPrefixes=
 org.eclipse.jdt.core.codeComplete.staticFinalFieldSuffixes=
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.methodParameters=generate
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=1.8
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
@@ -104,7 +102,6 @@ org.eclipse.jdt.core.compiler.problem.unusedPrivateMember=warning
 org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning
 org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
 org.eclipse.jdt.core.compiler.processAnnotations=disabled
-org.eclipse.jdt.core.compiler.source=1.8
 org.eclipse.jdt.core.formatter.align_fields_grouping_blank_lines=2147483647
 org.eclipse.jdt.core.formatter.align_type_members_on_columns=false
 org.eclipse.jdt.core.formatter.alignment_for_arguments_in_allocation_expression=16