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lib/src/main/java/zeroecho/data/processing/PlainBytes.java

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+/*******************************************************************************
+ * Copyright (C) 2025, Leo Galambos
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * 3. All advertising materials mentioning features or use of this software must
+ *    display the following acknowledgement:
+ *    This product includes software developed by the Egothor project.
+ * 
+ * 4. Neither the name of the copyright holder nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ ******************************************************************************/
+package zeroecho.data.processing;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import zeroecho.data.DataContent;
+import zeroecho.data.PlainContent;
+
+/**
+ * An implementation of {@link PlainContent} that encapsulates a byte array.
+ * 
+ * Provides read-only access to the content through an {@link InputStream}
+ * backed by the internal byte buffer.
+ * 
+ * This class represents the start of a {@link DataContent} processing chain,
+ * thus it does not accept input from preceding content.
+ * 
+ * @author Leo Galambos
+ */
+public class PlainBytes implements PlainContent {
+    /**
+     * Logger instance for the {@code PlainBytes} class used to log runtime
+     * information, warnings, or errors. It is statically initialized with the class
+     * name to ensure consistent logging context throughout the class.
+     */
+    private static final Logger LOG = Logger.getLogger(PlainBytes.class.getName());
+    /**
+     * Byte array buffer that holds the raw data managed by this instance.
+     */
+    protected final byte[] buffer;
+
+    /**
+     * Constructs a new {@code PlainBytes} instance by copying the provided byte
+     * array.
+     *
+     * @param buffer the byte array to wrap
+     */
+    public PlainBytes(final byte[] buffer) {
+        Objects.requireNonNull(buffer, "PlainBytes cannot operate with null buffer");
+
+        this.buffer = Arrays.copyOf(buffer, buffer.length);
+    }
+
+    /**
+     * Constructs a new {@code PlainBytes} instance with a buffer of the specified
+     * length.
+     *
+     * @param length the size of the internal byte buffer to allocate
+     * @throws NegativeArraySizeException if {@code length} is negative
+     */
+    protected PlainBytes(final int length) {
+        this.buffer = new byte[length];
+    }
+
+    /**
+     * {@inheritDoc}
+     * 
+     * {@code PlainBytes} represents the start of a {@link DataContent} chain and
+     * therefore must not have any input. Calling this method with a
+     * non-{@code null} argument will result in an exception.
+     * 
+     *
+     * @param input the preceding {@link DataContent}, which must be {@code null}
+     * @throws IllegalArgumentException if {@code input} is not {@code null}
+     */
+    @Override
+    public void setInput(final DataContent input) {
+        if (input != null) {
+            throw new IllegalArgumentException(
+                    getClass().getName() + " must be the first element in a DataContent chain; it cannot accept input");
+        }
+    }
+
+    /**
+     * Returns an {@link InputStream} for reading the byte array.
+     *
+     * @return a new {@link ByteArrayInputStream}
+     * @throws IOException if an I/O error occurs
+     */
+    @Override
+    public InputStream getStream() throws IOException {
+        LOG.log(Level.INFO, "opening byte array for read, length={0}", buffer.length);
+
+        return new ByteArrayInputStream(buffer);
+    }
+
+    /**
+     * Returns a copy of the internal byte buffer.
+     *
+     * @return a new byte array containing the data from the internal buffer
+     */
+    @Override
+    public byte[] toBytes() {
+        return Arrays.copyOf(buffer, buffer.length);
+    }
+}