PlistFileWriter: fix 'Potential resource leak' warnings

Author: EcljpseB0T

bundles/org.eclipse.urischeme/src/org/eclipse/urischeme/internal/registration/PlistFileWriter.java

@@ -58,14 +58,14 @@ public class PlistFileWriter {
 
 	/**
 	 * Creates an instance of the PlistFileWriter. Throws an
-	 * {@link IllegalStateException} if the given {@link Reader} does not provide
+	 * {@link IllegalStateException} if the supplied {@link Reader} does not provide
 	 * .plist file.
 	 *
-	 * @param reader The file reader of the .plist file
+	 * @param reader The supplier of file reader of the .plist file
 	 *
 	 * @throws IllegalArgumentException if file cannot be understood as .plist file
 	 */
-	public PlistFileWriter(Reader reader) {
+	public PlistFileWriter(IOSupplier<Reader> reader) {
 		this.document = getDom(reader);
 		this.array = getOrCreateBundleUrlTypesAndArray();
 	}
@@ -167,13 +167,18 @@ public void removeScheme(String scheme) {
 		arrayNode.removeChild(dict);
 	}
 
+	@FunctionalInterface
+	public interface IOSupplier<T> {
+		T get() throws IOException;
+	}
+	
 	/**
-	 * Writes the content (xml) of the .plist file to the given {@link Writer}
+	 * Writes the content (xml) of the .plist file to the supplied {@link Writer}
 	 *
-	 * @param writer The Writer to which the xml should be written to, e.g.
-	 *               {@link BufferedWriter}
+	 * @param writer The Supplier for a Writer to which the xml should be written
+	 *               to, e.g. {@link BufferedWriter}
 	 */
-	public void writeTo(Writer writer) {
+	public void writeTo(IOSupplier<Writer> writer) {
 		boolean hasDict = false;
 		for (int i = 0; i < array.getChildNodes().getLength(); i++) {
 			Node child = array.getChildNodes().item(i);
@@ -197,8 +202,8 @@ public void writeTo(Writer writer) {
 		transformDocument(writer);
 	}
 
-	private void transformDocument(Writer writer) {
-		try (writer) {
+	private void transformDocument(IOSupplier<Writer> supplier) {
+		try (Writer writer = supplier.get()) {
 			DOMSource source = new DOMSource(this.document);
 			@SuppressWarnings("restriction")
 			TransformerFactory f = org.eclipse.core.internal.runtime.XmlProcessorFactory
@@ -209,11 +214,12 @@ private void transformDocument(Writer writer) {
 		}
 	}
 
-	@SuppressWarnings("restriction")
-	private Document getDom(Reader reader) {
-		try (reader) {
-			return org.eclipse.core.internal.runtime.XmlProcessorFactory
-					.parseWithErrorOnDOCTYPE(new InputSource(reader));
+	private Document getDom(IOSupplier<Reader> supplier) {
+		try (Reader reader = supplier.get()) {
+			@SuppressWarnings("restriction")
+			Document withErrorOnDOCTYPE = org.eclipse.core.internal.runtime.XmlProcessorFactory
+			.parseWithErrorOnDOCTYPE(new InputSource(reader));
+			return withErrorOnDOCTYPE;
 		} catch (ParserConfigurationException | IOException | SAXException e) {
 			throw new IllegalArgumentException(e);
 		}

bundles/org.eclipse.urischeme/src/org/eclipse/urischeme/internal/registration/RegistrationMacOsX.java

@@ -10,7 +10,6 @@
  *******************************************************************************/
 package org.eclipse.urischeme.internal.registration;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -117,8 +116,8 @@ private String determineHandlerLocation(String lsRegisterDump, String scheme) {
 				.orElse(""); //$NON-NLS-1$
 	}
 
-	private PlistFileWriter getPlistFileWriter(String plistPath) throws IOException {
-		return new PlistFileWriter(fileProvider.newReader(plistPath));
+	private PlistFileWriter getPlistFileWriter(String plistPath) {
+		return new PlistFileWriter(() -> fileProvider.newReader(plistPath));
 	}
 
 	@Override
@@ -131,8 +130,7 @@ private void registerAppWithLsregister(String pathToEclipseApp) throws Exception
 		processExecutor.execute(LSREGISTER, RECURSIVE, pathToEclipseApp);
 	}
 
-	private void changePlistFile(Collection<IScheme> toAdd, Collection<IScheme> toRemove, String pathToEclipseApp)
-			throws IOException {
+	private void changePlistFile(Collection<IScheme> toAdd, Collection<IScheme> toRemove, String pathToEclipseApp) {
 		String plistPath = pathToEclipseApp + PLIST_PATH_SUFFIX;
 
 		PlistFileWriter writer = getPlistFileWriter(plistPath);
@@ -145,7 +143,7 @@ private void changePlistFile(Collection<IScheme> toAdd, Collection<IScheme> toRe
 			writer.removeScheme(scheme.getName());
 		}
 
-		writer.writeTo(fileProvider.newWriter(plistPath));
+		writer.writeTo(() -> fileProvider.newWriter(plistPath));
 	}
 
 	/**

tests/org.eclipse.tests.urischeme/src/org/eclipse/urischeme/internal/registration/TestUnitPlistFileWriter.java

@@ -82,7 +82,7 @@ public void doesntRemoveCommentAfterEndArrayTag() {
 		String xml = getPlistStartXmlSnippet() + "	<key>CFBundleURLTypes</key>\n" + "		<array>\n"
 				+ getSchemeXmlSnippet("other") + "		</array>\n" + "<!--comment-->\n" + getPlistEndXmlSnippet();
 
-		PlistFileWriter writer = new PlistFileWriter(new StringReader(xml));
+		PlistFileWriter writer = new PlistFileWriter(() -> new StringReader(xml));
 
 		writer.addScheme("adt", "adtScheme");
 
@@ -97,7 +97,7 @@ public void doesntRemoveCommentAfterEndArrayTag() {
 	public void doesntRemoveCommentBeforeEndArrayTag() {
 		String xml = getPlistStartXmlSnippet() + "	<key>CFBundleURLTypes</key>\n" + "		<array>\n"
 				+ getSchemeXmlSnippet("other") + "<!--comment-->" + "		</array>\n" + getPlistEndXmlSnippet();
-		PlistFileWriter writer = new PlistFileWriter(new StringReader(xml));
+		PlistFileWriter writer = new PlistFileWriter(() -> new StringReader(xml));
 
 		writer.addScheme("adt", "adtScheme");
 
@@ -183,25 +183,25 @@ public void removesEmptyCFBundleURLTypesEntry() {
 
 	@Test(expected = IllegalArgumentException.class)
 	public void throwsExceptionOnEmptyDocument() {
-		new PlistFileWriter(new StringReader(""));
+		new PlistFileWriter(() -> new StringReader(""));
 	}
 
 	@Test(expected = IllegalStateException.class)
 	public void throwsExceptionOnWrongPlistFile() {
 		String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>" + "<plist version=\"1.0\"/>";
-		new PlistFileWriter(new StringReader(xml));
+		new PlistFileWriter(() -> new StringReader(xml));
 	}
 
 	@Test(expected = IllegalStateException.class)
 	public void throwsExceptionOnWrongXmlFile() {
 		String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>" + "<foo/>";
-		new PlistFileWriter(new StringReader(xml));
+		new PlistFileWriter(() -> new StringReader(xml));
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void throwsExceptionOnNonXmlFile() {
 		String xml = "foo bar";
-		new PlistFileWriter(new StringReader(xml));
+		new PlistFileWriter(() -> new StringReader(xml));
 	}
 
 	@Test
@@ -232,17 +232,17 @@ private void assertSchemesInOrder(PlistFileWriter writer, String... schemes) {
 	}
 
 	private void assertXml(String xml, PlistFileWriter writer) {
-		StringWriter stringWriter = new StringWriter();
-		writer.writeTo(stringWriter);
-		assertEquals(xml, stringWriter.toString().replaceAll("\r\n", "\n"));
+		StringWriter stringWriters[] = new StringWriter[1];
+		writer.writeTo(() -> (stringWriters[0] = new StringWriter()));
+		assertEquals(xml, stringWriters[0].toString().replaceAll("\r\n", "\n"));
 	}
 
 	private PlistFileWriter getWriter() {
-		return new PlistFileWriter(new StringReader(getXml()));
+		return new PlistFileWriter(() -> new StringReader(getXml()));
 	}
 
 	private PlistFileWriter getWriterWithSchemes(String... schemes) {
-		return new PlistFileWriter(new StringReader(getXml(schemes)));
+		return new PlistFileWriter(() -> new StringReader(getXml(schemes)));
 	}
 
 	private String getXml() {
@@ -257,7 +257,7 @@ private String getXml(String[] schemes) {
 			}
 		}
 		return getPlistStartXmlSnippet() + "	<key>CFBundleURLTypes</key>\n" + "		<array>\n"
-				+ snippets.append("		</array>\n").append(getPlistEndXmlSnippet()).toString();
+		+ snippets.append("		</array>\n").append(getPlistEndXmlSnippet()).toString();
 	}
 
 	private String getPlistStartXmlSnippet() {