Merge branch '__rultor'

src/main/java/org/cactoos/io/HeadInput.java

@@ -0,0 +1,63 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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.IOException;
+import java.io.InputStream;
+import org.cactoos.Input;
+
+/**
+ * Input that only shows the first N bytes of the original input.
+ *
+ * @author Roman Proshin (roman@proshin.org)
+ * @version $Id$
+ * @since 0.31
+ */
+public final class HeadInput implements Input {
+
+    /**
+     * The original input.
+     */
+    private final Input origin;
+
+    /**
+     * Limit of bytes that can be read from the beginning.
+     */
+    private final int length;
+
+    /**
+     * Ctor.
+     * @param orig The original input.
+     * @param len Limit of bytes that can be read from the beginning.
+     */
+    public HeadInput(final Input orig, final int len) {
+        this.origin = orig;
+        this.length = len;
+    }
+
+    @Override
+    public InputStream stream() throws IOException {
+        return new HeadInputStream(this.origin.stream(), this.length);
+    }
+}

src/main/java/org/cactoos/io/HeadInputStream.java

@@ -0,0 +1,123 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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.IOException;
+import java.io.InputStream;
+
+/**
+ * Input stream that only shows the first N bytes of the original stream.
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Roman Proshin (roman@proshin.org)
+ * @version $Id$
+ * @since 0.31
+ */
+public final class HeadInputStream extends InputStream {
+
+    /**
+     * Original input stream.
+     */
+    private final InputStream origin;
+
+    /**
+     * A number of bytes that can be read from the beginning.
+     */
+    private final long length;
+
+    /**
+     * Current number or read bytes.
+     */
+    private long processed;
+
+    /**
+     * Ctor.
+     * @param orig The original input stream.
+     * @param len A number of bytes that can be read from the beginning.
+     */
+    public HeadInputStream(final InputStream orig, final int len) {
+        super();
+        this.origin = orig;
+        this.length = len;
+    }
+
+    @Override
+    public int read() throws IOException {
+        final int adjusted;
+        if (this.processed >= this.length) {
+            adjusted = -1;
+        } else {
+            this.processed = this.processed + 1;
+            adjusted = this.origin.read();
+        }
+        return adjusted;
+    }
+
+    @Override
+    public long skip(final long skip) throws IOException {
+        final long adjusted;
+        if (this.processed + skip > this.length) {
+            adjusted = this.length - this.processed;
+        } else {
+            adjusted = skip;
+        }
+        final long skipped = this.origin.skip(adjusted);
+        this.processed = this.processed + skipped;
+        return skipped;
+    }
+
+    @Override
+    public void reset() throws IOException {
+        this.processed = 0L;
+        this.origin.reset();
+    }
+
+    @Override
+    public int available() throws IOException {
+        final int available = this.origin.available();
+        final int adjusted;
+        if (this.processed + available > this.length) {
+            adjusted = (int) (this.length - this.processed);
+        } else {
+            adjusted = available;
+        }
+        return adjusted;
+    }
+
+    @Override
+    public void close() throws IOException {
+        this.origin.close();
+    }
+
+    @Override
+    public boolean markSupported() {
+        return this.origin.markSupported();
+    }
+
+    @Override
+    public void mark(final int readlimit) {
+        this.origin.mark(readlimit);
+    }
+}

src/test/java/org/cactoos/io/HeadInputStreamTest.java

@@ -0,0 +1,98 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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 org.cactoos.matchers.TextHasString;
+import org.cactoos.text.TextOf;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.core.IsEqual;
+import org.junit.Test;
+
+/**
+ * Test cases for {@link HeadInputStream}.
+ *
+ * @author Roman Proshin (roman@proshin.org)
+ * @version $Id$
+ * @since 0.31
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumberCheck (500 lines)
+ */
+public final class HeadInputStreamTest {
+
+    @Test
+    public void testSkippingLessThanTotal() throws Exception {
+        final HeadInputStream stream = new HeadInputStream(
+            new InputOf("testSkippingLessThanTotal").stream(),
+            5
+        );
+        stream.skip(3L);
+        MatcherAssert.assertThat(
+            "Incorrect head of the input stream has been read",
+            new TextOf(stream),
+            new TextHasString("tS")
+        );
+    }
+
+    @Test
+    public void testSkippingMoreThanTotal() throws Exception {
+        final HeadInputStream stream = new HeadInputStream(
+            new InputOf("testSkippingMoreThanTotal").stream(),
+            5
+        );
+        stream.skip(7L);
+        MatcherAssert.assertThat(
+            "The result text wasn't empty",
+            new TextOf(stream),
+            new TextHasString("")
+        );
+    }
+
+    @Test
+    public void testResetting() throws Exception {
+        final HeadInputStream stream = new HeadInputStream(
+            new InputOf("testResetting").stream(),
+            5
+        );
+        stream.skip(7L);
+        stream.reset();
+        MatcherAssert.assertThat(
+            "Reset didn't change the state",
+            new TextOf(stream),
+            new TextHasString("testR")
+        );
+    }
+
+    @Test
+    public void testAvailableLessThanTotal() throws Exception {
+        final HeadInputStream stream = new HeadInputStream(
+            new InputOf("testAvailableLessThanTotal").stream(),
+            5
+        );
+        MatcherAssert.assertThat(
+            "Count of available bytes is incorrect",
+            stream.available(),
+            new IsEqual<>(5)
+        );
+    }
+}

src/test/java/org/cactoos/io/HeadInputTest.java

@@ -0,0 +1,70 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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 org.cactoos.matchers.TextHasString;
+import org.cactoos.text.TextOf;
+import org.hamcrest.MatcherAssert;
+import org.junit.Test;
+
+/**
+ * Test cases for {@link HeadInput}.
+ *
+ * @author Roman Proshin (roman@proshin.org)
+ * @version $Id$
+ * @since 0.31
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumberCheck (500 lines)
+ */
+public final class HeadInputTest {
+
+    @Test
+    public void readsHeadOfLongerInput() throws Exception {
+        MatcherAssert.assertThat(
+            "HeadInput couldn't limit a number of read bytes",
+            new TextOf(
+                new HeadInput(
+                    new InputOf("readsHeadOfLongerInput"),
+                    5
+                )
+            ),
+            new TextHasString("reads")
+        );
+    }
+
+    @Test
+    public void readsHeadOfShorterInput() throws Exception {
+        final String input = "readsHeadOfShorterInput";
+        MatcherAssert.assertThat(
+            "HeadInput incorrectly limited a number of read bytes",
+            new TextOf(
+                new HeadInput(
+                    new InputOf(input),
+                    35
+                )
+            ),
+            new TextHasString(input)
+        );
+    }
+}