Fail operations when JarFile is closed

Update `JarFile` to track when the instance has been closed and throw
an exception in the same way that `ZipFile` does.

Closes gh-21072

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarFile.java

@@ -26,9 +26,13 @@ import java.net.URLStreamHandler;
 import java.net.URLStreamHandlerFactory;
 import java.util.Enumeration;
 import java.util.Iterator;
+import java.util.Spliterator;
+import java.util.Spliterators;
 import java.util.function.Supplier;
 import java.util.jar.JarInputStream;
 import java.util.jar.Manifest;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 import java.util.zip.ZipEntry;
 
 import org.springframework.boot.loader.data.RandomAccessData;
@@ -84,6 +88,8 @@ public class JarFile extends java.util.jar.JarFile implements Iterable<java.util
 
 	private String comment;
 
+	private volatile boolean closed;
+
 	/**
 	 * Create a new {@link JarFile} backed by the specified file.
 	 * @param file the root jar file
@@ -222,6 +228,13 @@ public class JarFile extends java.util.jar.JarFile implements Iterable<java.util
 		return new JarEntryEnumeration(this.entries.iterator());
 	}
 
+	@Override
+	public Stream<java.util.jar.JarEntry> stream() {
+		Spliterator<java.util.jar.JarEntry> spliterator = Spliterators.spliterator(iterator(), size(),
+				Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL);
+		return StreamSupport.stream(spliterator, false);
+	}
+
 	/**
 	 * Return an iterator for the contained entries.
 	 * @see java.lang.Iterable#iterator()
@@ -230,7 +243,7 @@ public class JarFile extends java.util.jar.JarFile implements Iterable<java.util
 	@Override
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public Iterator<java.util.jar.JarEntry> iterator() {
-		return (Iterator) this.entries.iterator();
+		return (Iterator) this.entries.iterator(this::ensureOpen);
 	}
 
 	public JarEntry getJarEntry(CharSequence name) {
@@ -248,11 +261,13 @@ public class JarFile extends java.util.jar.JarFile implements Iterable<java.util
 
 	@Override
 	public ZipEntry getEntry(String name) {
+		ensureOpen();
 		return this.entries.getEntry(name);
 	}
 
 	@Override
 	public synchronized InputStream getInputStream(ZipEntry entry) throws IOException {
+		ensureOpen();
 		if (entry instanceof JarEntry) {
 			return this.entries.getInputStream((JarEntry) entry);
 		}
@@ -322,22 +337,34 @@ public class JarFile extends java.util.jar.JarFile implements Iterable<java.util
 
 	@Override
 	public String getComment() {
+		ensureOpen();
 		return this.comment;
 	}
 
 	@Override
 	public int size() {
+		ensureOpen();
 		return this.entries.getSize();
 	}
 
 	@Override
 	public void close() throws IOException {
+		if (this.closed) {
+			return;
+		}
+		this.closed = true;
 		super.close();
 		if (this.type == JarFileType.DIRECT && this.parent == null) {
 			this.rootFile.close();
 		}
 	}
 
+	private void ensureOpen() {
+		if (this.closed) {
+			throw new IllegalStateException("zip file closed");
+		}
+	}
+
 	String getUrlString() throws MalformedURLException {
 		if (this.urlString == null) {
 			this.urlString = getUrl().toString();

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarFileEntries.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -47,6 +47,9 @@ import org.springframework.boot.loader.data.RandomAccessData;
  */
 class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 
+	private static final Runnable NO_VALIDATION = () -> {
+	};
+
 	private static final String META_INF_PREFIX = "META-INF/";
 
 	private static final Name MULTI_RELEASE = new Name("Multi-Release");
@@ -192,7 +195,11 @@ class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 
 	@Override
 	public Iterator<JarEntry> iterator() {
-		return new EntryIterator();
+		return new EntryIterator(NO_VALIDATION);
+	}
+
+	Iterator<JarEntry> iterator(Runnable validator) {
+		return new EntryIterator(validator);
 	}
 
 	boolean containsEntry(CharSequence name) {
@@ -347,17 +354,26 @@ class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 	/**
 	 * Iterator for contained entries.
 	 */
-	private class EntryIterator implements Iterator<JarEntry> {
+	private final class EntryIterator implements Iterator<JarEntry> {
+
+		private final Runnable validator;
 
 		private int index = 0;
 
+		private EntryIterator(Runnable validator) {
+			this.validator = validator;
+			validator.run();
+		}
+
 		@Override
 		public boolean hasNext() {
+			this.validator.run();
 			return this.index < JarFileEntries.this.size;
 		}
 
 		@Override
 		public JarEntry next() {
+			this.validator.run();
 			if (!hasNext()) {
 				throw new NoSuchElementException();
 			}

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java

@@ -30,17 +30,21 @@ import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.attribute.FileTime;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
+import java.util.Iterator;
 import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarInputStream;
 import java.util.jar.JarOutputStream;
 import java.util.jar.Manifest;
+import java.util.stream.Stream;
 import java.util.zip.CRC32;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
+import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -56,6 +60,7 @@ import org.springframework.util.StreamUtils;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIOException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
@@ -171,6 +176,12 @@ class JarFileTests {
 		assertThat(entry.getName()).isEqualTo("1.dat");
 	}
 
+	@Test
+	void getJarEntryWhenClosed() throws Exception {
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> this.jarFile.getJarEntry("1.dat"));
+	}
+
 	@Test
 	void getInputStream() throws Exception {
 		InputStream inputStream = this.jarFile.getInputStream(this.jarFile.getEntry("1.dat"));
@@ -180,23 +191,41 @@ class JarFileTests {
 		assertThat(inputStream.read()).isEqualTo(-1);
 	}
 
+	@Test
+	void getInputStreamWhenClosed() throws Exception {
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> this.jarFile.getInputStream(this.jarFile.getEntry("1.dat")));
+	}
+
 	@Test
 	void getComment() {
 		assertThat(this.jarFile.getComment()).isEqualTo("outer");
 	}
 
+	@Test
+	void getCommentWhenClosed() throws Exception {
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> this.jarFile.getComment());
+	}
+
 	@Test
 	void getName() {
 		assertThat(this.jarFile.getName()).isEqualTo(this.rootJarFile.getPath());
 	}
 
 	@Test
-	void getSize() throws Exception {
+	void size() throws Exception {
 		try (ZipFile zip = new ZipFile(this.rootJarFile)) {
 			assertThat(this.jarFile.size()).isEqualTo(zip.size());
 		}
 	}
 
+	@Test
+	void sizeWhenClosed() throws Exception {
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> this.jarFile.size());
+	}
+
 	@Test
 	void getEntryTime() throws Exception {
 		java.util.jar.JarFile jdkJarFile = new java.util.jar.JarFile(this.rootJarFile);
@@ -603,6 +632,41 @@ class JarFileTests {
 		}
 	}
 
+	@Test
+	void iterator() {
+		Iterator<JarEntry> iterator = this.jarFile.iterator();
+		List<String> names = new ArrayList<String>();
+		while (iterator.hasNext()) {
+			names.add(iterator.next().getName());
+		}
+		assertThat(names).hasSize(12).contains("1.dat");
+	}
+
+	@Test
+	void iteratorWhenClosed() throws IOException {
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> this.jarFile.iterator());
+	}
+
+	@Test
+	void iteratorWhenClosedLater() throws IOException {
+		Iterator<JarEntry> iterator = this.jarFile.iterator();
+		iterator.next();
+		this.jarFile.close();
+		assertThatZipFileClosedIsThrownBy(() -> iterator.hasNext());
+	}
+
+	@Test
+	void stream() {
+		Stream<String> stream = this.jarFile.stream().map(JarEntry::getName);
+		assertThat(stream).hasSize(12).contains("1.dat");
+
+	}
+
+	private void assertThatZipFileClosedIsThrownBy(ThrowingCallable throwingCallable) {
+		assertThatIllegalStateException().isThrownBy(throwingCallable).withMessage("zip file closed");
+	}
+
 	private int getJavaVersion() {
 		try {
 			Object runtimeVersion = Runtime.class.getMethod("version").invoke(null);