Add a MarkShieldInputStream
* Add a MarkShieldInputStream
* Update MarkShieldInputStream.java
Set since tag to 2.8.0
ADD
src/main/java/org/apache/commons/io/input/MarkShieldInputStream.java
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.commons.io.input;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * This is an alternative to {@link java.io.ByteArrayInputStream}
+ * which removes the synchronization overhead for non-concurrent
+ * access; as such this class is not thread-safe.
+ *
+ * Proxy stream that prevents the underlying input stream from being marked/reset.
+ * <p>
+ * This class is typically used in cases where an input stream that supports
+ * marking needs to be passed to a component that wants to explicitly mark
+ * the stream, but it it is not desirable to allow marking of the stream.
+ * </p>
+ *
+ * @since 2.8.0
+ */
+public class MarkShieldInputStream extends ProxyInputStream {
+
+ /**
+ * Creates a proxy that shields the given input stream from being
+ * marked or rest.
+ *
+ * @param in underlying input stream
+ */
+ public MarkShieldInputStream(final InputStream in) {
+ super(in);
+ }
+
+ @SuppressWarnings("sync-override")
+ @Override
+ public void mark(final int readlimit) {
+ // no-op
+ }
+
+ @Override
+ public boolean markSupported() {
+ return false;
+ }
+
+ @SuppressWarnings("sync-override")
+ @Override
+ public void reset() throws IOException {
+ throw new IOException("mark/reset not supported");
+ }
+}

ADD
src/test/java/org/apache/commons/io/input/MarkShieldInputStreamTest.java
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.commons.io.input;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class MarkShieldInputStreamTest {
+
+ @Test
+ public void markIsNoOpWhenUnderlyingDoesNotSupport() throws IOException {
+ try (final MarkTestableInputStream in = new MarkTestableInputStream(new NullInputStream(64, false, false));
+ final MarkShieldInputStream msis = new MarkShieldInputStream(in)) {
+
+ msis.mark(1024);
+
+ assertEquals(0, in.markcount);
+ assertEquals(0, in.readlimit);
+ }
+ }
+
+ @Test
+ public void markIsNoOpWhenUnderlyingSupports() throws IOException {
+ try (final MarkTestableInputStream in = new MarkTestableInputStream(new NullInputStream(64, true, false));
+ final MarkShieldInputStream msis = new MarkShieldInputStream(in)) {
+
+ msis.mark(1024);
+
+ assertEquals(0, in.markcount);
+ assertEquals(0, in.readlimit);
+ }
+ }
+
+ @Test
+ public void markSupportedIsFalseWhenUnderlyingFalse() throws IOException {
+ // test wrapping an underlying stream which does NOT support marking
+ try (final InputStream is = new NullInputStream(64, false, false)) {
+ assertFalse(is.markSupported());
+
+ try (final MarkShieldInputStream msis = new MarkShieldInputStream(is)) {
+ assertFalse(msis.markSupported());
+ }
+ }
+ }
+
+ @Test
+ public void markSupportedIsFalseWhenUnderlyingTrue() throws IOException {
+ // test wrapping an underlying stream which supports marking
+ try (final InputStream is = new NullInputStream(64, true, false)) {
+ assertTrue(is.markSupported());
+
+ try (final MarkShieldInputStream msis = new MarkShieldInputStream(is)) {
+ assertFalse(msis.markSupported());
+ }
+ }
+ }
+
+ @Test
+ public void resetThrowsExceptionWhenUnderylingDoesNotSupport() throws IOException {
+ // test wrapping an underlying stream which does NOT support marking
+ try (final MarkShieldInputStream msis = new MarkShieldInputStream(
+ new NullInputStream(64, false, false))) {
+ assertThrows(IOException.class, () -> msis.reset());
+ }
+ }
+
+ @Test
+ public void resetThrowsExceptionWhenUnderylingSupports() throws IOException {
+ // test wrapping an underlying stream which supports marking
+ try (final MarkShieldInputStream msis = new MarkShieldInputStream(
+ new NullInputStream(64, true, false))) {
+ assertThrows(IOException.class, () -> msis.reset());
+ }
+ }
+
+ private static class MarkTestableInputStream extends ProxyInputStream {
+ int markcount;
+ int readlimit;
+
+ public MarkTestableInputStream(final InputStream in) {
+ super(in);
+ }
+
+ @SuppressWarnings("sync-override")
+ @Override
+ public void mark(final int readlimit) {
+ // record that `mark` was called
+ this.markcount++;
+ this.readlimit = readlimit;
+
+ // invoke on super
+ super.mark(readlimit);
+ }
+ }
+}

Add a MarkShieldInputStream (#119)

* Add a MarkShieldInputStream

* Update MarkShieldInputStream.java

Set since tag to 2.8.0

Co-authored-by: Gary Gregory <garydgregory@users.noreply.github.com>