Repository: yegor256/cactoos
Pull request #1736 (2024-10-21 07:51:41)

Add InputWithRetry 
Add InputWithRetry with retry logic on Input stream


@yegor256 Is this something you meant in this [Issue](https://github.com/yegor256/cactoos/issues/1735)


Patch:
diff --git a/src/main/java/org/cactoos/io/InputWithRetry.java b/src/main/java/org/cactoos/io/InputWithRetry.java
new file mode 100644
index 00000000..fc09b602
--- /dev/null
+++ b/src/main/java/org/cactoos/io/InputWithRetry.java
@@ -0,0 +1,77 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2024 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.cactoos.io;
+
+import java.io.InputStream;
+import java.time.Duration;
+import org.cactoos.Input;
+import org.cactoos.func.Retry;
+
+/**
+ * Input with retry.
+ *
+ * @since 1.0
+ */
+public final class InputWithRetry implements Input {
+
+    /**
+     * Retry mechanism for {@link Input} operations, attempting to open
+     * an {@link InputStream} multiple times in case of failure.
+     *
+     * <p>The retry logic wraps around the {@link Input#stream()} method,
+     * enabling conditional reattempts according to the provided retry
+     * strategy. The number of attempts and the duration between attempts
+     * are configurable through the {@link Retry} instance.
+     */
+    private final Retry<Input, InputStream> retry;
+
+    /**
+     * The original {@link Input} instance to be used for retry operations.
+     *
+     * <p>This input provides the underlying data stream that the retry
+     * mechanism will attempt to read from. It is passed into the
+     * {@link Retry} logic to enable multiple attempts at accessing the
+     * input stream in case of failure.
+     */
+    private final Input input;
+
+    public InputWithRetry(final Input main, final int att) {
+        this(main, new Retry<>(Input::stream, att));
+    }
+
+    private InputWithRetry(final Input input, final Retry<Input, InputStream> retry) {
+        this.input = input;
+        this.retry = retry;
+    }
+
+    public InputWithRetry(final Input main, final int att, final Duration dur) {
+        this(main, new Retry<>(Input::stream, att, dur));
+    }
+
+    @Override
+    public InputStream stream() throws Exception {
+        return this.retry.apply(this.input);
+    }
+}


Test patch:
diff --git a/src/test/java/org/cactoos/io/InputWithRetryTest.java b/src/test/java/org/cactoos/io/InputWithRetryTest.java
new file mode 100644
index 00000000..b1007665
--- /dev/null
+++ b/src/test/java/org/cactoos/io/InputWithRetryTest.java
@@ -0,0 +1,79 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2024 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.cactoos.io;
+
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.hamcrest.core.IsEqual;
+import org.junit.jupiter.api.Test;
+import org.llorllale.cactoos.matchers.Assertion;
+import org.llorllale.cactoos.matchers.Throws;
+
+/**
+ * Test case for {@link InputWithRetry}.
+ *
+ * @since 1.0
+ */
+final class InputWithRetryTest {
+
+    @Test
+    void testInputWithRetryShouldRead() throws Exception {
+        final AtomicInteger cnt = new AtomicInteger(0);
+        final InputWithRetry iwr = new InputWithRetry(
+            () -> {
+                if (cnt.getAndIncrement() < 2) {
+                    throw new IllegalArgumentException("Test exception");
+                }
+                return new DeadInputStream();
+            },
+            3,
+            Duration.ZERO
+        );
+        new Assertion<>(
+            "should read -1 from stream",
+            iwr.stream().read(),
+            new IsEqual<>(-1)
+        ).affirm();
+    }
+
+    @Test
+    void testExceededNumberOfAttempts() {
+        final AtomicInteger cnt = new AtomicInteger(0);
+        final InputWithRetry iwr = new InputWithRetry(
+            () -> {
+                if (cnt.getAndIncrement() < 3) {
+                    throw new IllegalArgumentException("Test exception");
+                }
+                return new DeadInputStream();
+            },
+            3
+        );
+        new Assertion<>(
+            "should throw same exception",
+            iwr::stream,
+            new Throws<>(IllegalArgumentException.class)
+        ).affirm();
+    }
+}