From 196ab0fc031d6987c87e8c5d257c39f664ec9151 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Roland=20H=C3=A4der?= <roland@mxchange.org>
Date: Sun, 6 Dec 2020 05:20:03 +0100
Subject: [PATCH] Continued: - added more parameter validation - added
 commented-out noisy debug lines - rewrote more assert() calls to thrown
 exceptions (not private methods)
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Signed-off-by: Roland Häder <roland@mxchange.org>
---
 .../main/classes/index/class_BaseIndex.php    |  32 ++--
 .../classes/stacker/class_BaseStacker.php     | 142 ++++++++++++++----
 .../stacker/fifo/class_FiFoStacker.php        |  41 ++++-
 .../stacker/file/class_BaseFileStack.php      | 105 ++++++++++---
 .../stacker/file/fifo/class_FiFoFileStack.php |  74 ++++++++-
 .../stacker/filo/class_FiLoStacker.php        |  40 ++++-
 6 files changed, 366 insertions(+), 68 deletions(-)

diff --git a/framework/main/classes/index/class_BaseIndex.php b/framework/main/classes/index/class_BaseIndex.php
index 6f0c5a14..0392f36b 100644
--- a/framework/main/classes/index/class_BaseIndex.php
+++ b/framework/main/classes/index/class_BaseIndex.php
@@ -76,7 +76,7 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 	 * Reads the file header
 	 *
 	 * @return	void
-	 * @throws	UnexpectedValueException	If header length is invalid
+	 * @throws	UnexpectedValueException	If header length or count of elements is invalid
 	 */
 	public function readFileHeader () {
 		// First rewind to beginning as the header sits at the beginning ...
@@ -87,7 +87,7 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 		$data = $this->getIteratorInstance()->read($this->getIteratorInstance()->getHeaderSize());
 
 		// Have all requested bytes been read?
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('Read %d bytes (%d wanted).', strlen($data), $this->getIteratorInstance()->getHeaderSize()));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: Read %d bytes (%d wanted).', strlen($data), $this->getIteratorInstance()->getHeaderSize()));
 		if (strlen($data) != $this->getIteratorInstance()->getHeaderSize()) {
 			// Invalid header length
 			throw new UnexpectedValueException(sprintf('data(%d)=%s is not expected length %d',
@@ -117,22 +117,26 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 		 */
 		$header = explode(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA), $data);
 
-		// Set it here
-		$this->getIteratorInstance()->setHeader($header);
-
 		// Check if the array has only 3 elements
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('header(%d)=%s', count($header), print_r($header, true)));
-		assert(count($header) == 2);
-
-		// Check magic
-		assert($header[0] == self::INDEX_MAGIC);
-
-		// Check length of count
-		assert(strlen($header[1]) == BaseBinaryFile::LENGTH_COUNT);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: header()=%d', count($header)));
+		//* PRINTR-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: header(%d)=%s', count($header), print_r($header, true)));
+		if (count($header) != 2) {
+			// Bad header
+			throw new UnexpectedValueException(sprintf('header()=%d is not expected value 2', count($header)));
+		} elseif ($header[0] !== self::INDEX_MAGIC) {
+			// Magic must be in first element
+			throw new UnexpectedValueException(sprintf('header[0]=%s is not the expected magic (%s)', $header[0], self::INDEX_MAGIC));
+		} elseif (strlen($header[1]) != BaseBinaryFile::LENGTH_COUNT) {
+			// Length of total entries not matching
+			throw new UnexpectedValueException(sprintf('header[1](%d)=%s does not have expected length %d', strlen($header[1]), $header[1], BaseBinaryFile::LENGTH_COUNT));
+		}
 
 		// Decode count
 		$header[1] = hex2bin($header[1]);
 
+		// Set it here
+		$this->getIteratorInstance()->setHeader($header);
+
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: EXIT!');
 	}
@@ -175,7 +179,7 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 	 */
 	protected function initIndex (SplFileInfo $fileInfoInstance) {
 		// Get a file i/o pointer instance for index file
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('fileInfoInstance[%s]=%s - CALLED!', get_class($fileInfoInstance), $fileInfoInstance));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: fileInfoInstance[%s]=%s - CALLED!', get_class($fileInfoInstance), $fileInfoInstance));
 		$fileInstance = ObjectFactory::createObjectByConfiguredName('index_file_class', array($fileInfoInstance, $this));
 
 		// Get iterator instance
diff --git a/framework/main/classes/stacker/class_BaseStacker.php b/framework/main/classes/stacker/class_BaseStacker.php
index 9e44c9b4..70c6a229 100644
--- a/framework/main/classes/stacker/class_BaseStacker.php
+++ b/framework/main/classes/stacker/class_BaseStacker.php
@@ -8,6 +8,7 @@ use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
 
 // Import SPL stuff
 use \BadMethodCallException;
+use \InvalidArgumentException;
 
 /**
  * A general Stacker
@@ -55,30 +56,51 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 * @param	$stackerName	Name of the stack
 	 * @param	$forceReInit	Force re-initialization
 	 * @return	void
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	AlreadyInitializedStackerException	If the stack is already initialized
 	 */
 	public function initStack (string $stackerName, bool $forceReInit = false) {
-		// Is the stack already initialized?
-		if (($forceReInit === false) && ($this->isStackInitialized($stackerName))) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s,forceReInit=%d - CALLED!', $stackerName, intval($forceReInit)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (($forceReInit === false) && ($this->isStackInitialized($stackerName))) {
 			// Then throw the exception
+			// @TODO Change to BMCE
 			throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
-		} // END - if
+		}
 
 		// Initialize the given stack
 		$this->initGenericArrayKey('stacks', $stackerName, 'entries', $forceReInit);
+
+		// Trace message
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-STACKER: EXIT!');
 	}
 
 	/**
 	 * Initializes all stacks
 	 *
 	 * @return	void
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 */
 	public function initStacks (array $stacks, bool $forceReInit = false) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stacks()=%d,forceReInit=%d - CALLED!', count($stacks), intval($forceReInit)));
+		if (count($stacks) == 0) {
+			// No empty stack name
+			throw new InvalidArgumentException('Array "stacks" is empty');
+		}
+
 		// "Walk" through all (more will be added as needed
 		foreach ($stacks as $stackerName) {
 			// Init this stack
+			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: Calling this->initStack(%s,%d) ...', $stackerName, intval($forceReInit)));
 			$this->initStack($stackerName, $forceReInit);
-		} // END - foreach
+		}
+
+		// Trace message
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-STACKER: EXIT!');
 	}
 
 	/**
@@ -86,12 +108,21 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$isInitialized	Whether the stack is initialized
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 */
 	public function isStackInitialized (string $stackerName) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Is is there?
 		$isInitialized = ($this->isValidGenericArrayKey('stacks', $stackerName, 'entries'));
 
 		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: isInitialized=%d - EXIT!', intval($isInitialized)));
 		return $isInitialized;
 	}
 
@@ -100,19 +131,25 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$isFull			Whether the stack is full
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If given stack is missing
 	 */
 	protected function isStackFull (string $stackerName) {
-		// Is the stack not yet initialized?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} // END - if
+		}
 
 		// So, is the stack full?
 		$isFull = (($this->getStackCount($stackerName)) == FrameworkBootstrap::getConfigurationInstance()->getConfigEntry('stacker_' . $stackerName . '_max_size'));
 
 		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: isFull=%d - EXIT!', intval($isFull)));
 		return $isFull;
 	}
 
@@ -121,19 +158,25 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName		Name of the stack
 	 * @return	$isEmpty			Whether the stack is empty
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If given stack is missing
 	 */
 	public function isStackEmpty (string $stackerName) {
-		// Is the stack not yet initialized?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} // END - if
+		}
 
 		// So, is the stack empty?
 		$isEmpty = (($this->getStackCount($stackerName)) == 0);
 
 		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: isEmpty=%d - EXIT!', intval($isEmpty)));
 		return $isEmpty;
 	}
 
@@ -142,19 +185,25 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$count			Size of stack (array count)
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If given stack is missing
 	 */
 	public function getStackCount (string $stackerName) {
-		// Is the stack not yet initialized?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} // END - if
+		}
 
 		// Now, count the array of entries
 		$count = $this->countGenericArrayElements('stacks', $stackerName, 'entries');
 
 		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: count=%d - EXIT!', $count));
 		return $count;
 	}
 
@@ -164,13 +213,19 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 * @param	$stackerName	Name of the stack
 	 * @param	$value			Value to add to this stacker
 	 * @return	void
+	 * @throws	InvalidArgumentException	If a parameter is invalid
+	 * @throws	BadMethodCallException	If given stack is missing
 	 * @throws	FullStackerException	Thrown if the stack is full
 	 */
 	protected function addValue (string $stackerName, $value) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Then do it here
-			$this->initStack($stackerName);
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s,value[]=%s - CALLED!', $stackerName, gettype($value)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
+			// Throw an exception
+			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 		} elseif ($this->isStackFull($stackerName)) {
 			// Stacker is full
 			throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
@@ -178,6 +233,9 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 
 		// Now add the value to the stack
 		$this->pushValueToGenericArrayKey('stacks', $stackerName, 'entries', $value);
+
+		// Trace message
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-STACKER: EXIT!');
 	}
 
 	/**
@@ -185,12 +243,17 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	protected function getLastValue (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 		} elseif ($this->isStackEmpty($stackerName)) {
@@ -202,6 +265,7 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 		$value = $this->getGenericArrayElement('stacks', $stackerName, 'entries', $this->getStackCount($stackerName) - 1);
 
 		// Return it
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -210,12 +274,17 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	protected function getFirstValue (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 		} elseif ($this->isStackEmpty($stackerName)) {
@@ -227,6 +296,7 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 		$value = $this->getGenericArrayElement('stacks', $stackerName, 'entries', 0);
 
 		// Return it
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -235,12 +305,17 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "poped" from array
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	protected function popLast (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 		} elseif ($this->isStackEmpty($stackerName)) {
@@ -249,7 +324,11 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 		}
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
-		return $this->popGenericArrayElement('stacks', $stackerName, 'entries');
+		$value = $this->popGenericArrayElement('stacks', $stackerName, 'entries');
+
+		// Return it
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
+		return $value;
 	}
 
 	/**
@@ -257,12 +336,17 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "shifted" from array
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	protected function popFirst (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (!$this->isStackInitialized($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(sprintf('stackerName=%s not yet initialized but method called.', $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 		} elseif ($this->isStackEmpty($stackerName)) {
@@ -271,7 +355,11 @@ abstract class BaseStacker extends BaseFrameworkSystem {
 		}
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
-		return $this->shiftGenericArrayElement('stacks', $stackerName, 'entries');
+		$value = $this->shiftGenericArrayElement('stacks', $stackerName, 'entries');
+
+		// Return it
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
+		return $value;
 	}
 
 }
diff --git a/framework/main/classes/stacker/fifo/class_FiFoStacker.php b/framework/main/classes/stacker/fifo/class_FiFoStacker.php
index 1e4743f8..aafe1178 100644
--- a/framework/main/classes/stacker/fifo/class_FiFoStacker.php
+++ b/framework/main/classes/stacker/fifo/class_FiFoStacker.php
@@ -2,6 +2,9 @@
 // Own namespace
 namespace Org\Mxchange\CoreFramework\Stack;
 
+// Import SPL stuff
+use \InvalidArgumentException;
+
 /**
  * A FiFo Stacker class
  *
@@ -57,11 +60,23 @@ class FiFoStacker extends BaseStacker implements Stackable {
 	 * @param	$stackerName	Name of the stack
 	 * @param	$value			Value to push on it
 	 * @return	void
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	StackerFullException	If the stack is full
 	 */
 	public function pushNamed (string $stackerName, $value) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s,value[]=%s - CALLED!', $stackerName, gettype($value)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Call the protected method
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: Calling parent::addValue(%s,%s) ...', $stackerName, gettype($value)));
 		parent::addValue($stackerName, $value);
+
+		// Trace message
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-STACKER: EXIT!');
 	}
 
 	/**
@@ -69,17 +84,28 @@ class FiFoStacker extends BaseStacker implements Stackable {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of the current stack entry
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function popNamed (string $stackerName) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Get the value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: Calling this->getNamed(%s) ...', $stackerName));
 		$value = $this->getNamed($stackerName);
 
 		// Call the protected method
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: Calling parent::popFirst(%s) ...', $stackerName));
 		parent::popFirst($stackerName);
 
 		// Return the value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -88,12 +114,25 @@ class FiFoStacker extends BaseStacker implements Stackable {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function getNamed (string $stackerName) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Call the protected method
-		return parent::getFirstValue($stackerName);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: Calling parent::getFirstValue(%s) ...', $stackerName));
+		$value = parent::getFirstValue($stackerName);
+
+		// Return value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-STACKER: value[]=%s - EXIT!', gettype($value)));
+		return $value;
 	}
 
 }
diff --git a/framework/main/classes/stacker/file/class_BaseFileStack.php b/framework/main/classes/stacker/file/class_BaseFileStack.php
index 0052a8cb..5513c777 100644
--- a/framework/main/classes/stacker/file/class_BaseFileStack.php
+++ b/framework/main/classes/stacker/file/class_BaseFileStack.php
@@ -70,7 +70,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 */
 	public function readFileHeader () {
 		// First rewind to beginning as the header sits at the beginning ...
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: CALLED!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: CALLED!');
 		$this->getIteratorInstance()->rewind();
 
 		// Then read it (see constructor for calculation)
@@ -160,7 +160,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 */
 	public function flushFileHeader () {
 		// Put all informations together
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: CALLED!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: CALLED!');
 		$header = sprintf('%s%s%s%s%s%s',
 			// Magic
 			StackableFile::STACK_MAGIC,
@@ -185,7 +185,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		$this->getIteratorInstance()->writeData(0, $header, false);
 
 		// Trace message
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: EXIT!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -250,6 +250,9 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 
 		// And set it here
 		$this->setIndexInstance($indexInstance);
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -259,12 +262,16 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 * @param	$value			Value to add to this stacker
 	 * @return	void
 	 * @throws	FullStackerException	If the stack is full
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	InvalidArgumentException	Not all variable types are wanted here
 	 */
 	protected function addValue (string $stackerName, $value) {
-		// Do some tests
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('stackerName=%s,value[%s]=%s - CALLED!', $stackerName, gettype($value), print_r($value, true)));
-		if ($this->isStackFull($stackerName)) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s,value[%s]=%s - CALLED!', $stackerName, gettype($value), print_r($value, true)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif ($this->isStackFull($stackerName)) {
 			// Stacker is full
 			throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 		} elseif (is_resource($value) || is_object($value)) {
@@ -280,6 +287,9 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 
 		// Add the hash and gap position to the index
 		$this->getIndexInstance()->addHashToIndex($stackerName, $data);
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -287,20 +297,26 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	BadMethodCallException	If the stack is empty
 	 */
 	protected function getLastValue (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if ($this->isStackEmpty($stackerName)) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		} // END - if
+		}
 
 		// Now get the last value
 		/* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 		$value = NULL;
 
 		// Return it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -309,20 +325,26 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	BadMethodCallException	If the stack is empty
 	 */
 	protected function getFirstValue (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if ($this->isStackEmpty($stackerName)) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		} // END - if
+		}
 
 		// Now get the first value
 		/* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 		$value = NULL;
 
 		// Return it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -331,14 +353,19 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "poped" from array
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	BadMethodCallException	If the stack is empty
 	 */
 	protected function popLast (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if ($this->isStackEmpty($stackerName)) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		} // END - if
+		}
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
 		/* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
@@ -350,14 +377,19 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "shifted" from array
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	protected function popFirst (string $stackerName) {
-		// Is the stack not yet initialized or full?
-		if ($this->isStackEmpty($stackerName)) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new BadMethodCallException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		} // END - if
+		}
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
 		/* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
@@ -369,13 +401,22 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$isFull			Whether the stack is full
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 */
 	protected function isStackFull (string $stackerName) {
-		// File-based stacks will only run full if the disk space is low.
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// @TODO Please implement this, returning false
+		/* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 		$isFull = false;
 
 		// Return result
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: isFull=%d - EXIT!', intval($isFull)));
 		return $isFull;
 	}
 
@@ -384,13 +425,22 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 *
 	 * @param	$stackerName		Name of the stack
 	 * @return	$isEmpty			Whether the stack is empty
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 * @throws	BadMethodCallException	If given stack is missing
 	 */
 	public function isStackEmpty (string $stackerName) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// So, is the stack empty?
 		$isEmpty = (($this->getStackCount($stackerName)) == 0);
 
 		// Return result
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: isEmpty=%d - EXIT!', intval($isEmpty)));
 		return $isEmpty;
 	}
 
@@ -445,7 +495,12 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 */
 	public function getStackCount (string $stackerName) {
 		// Now, simply return the found count value, this must be up-to-date then!
-		return $this->getIteratorInstance()->getCounter();
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		$count = $this->getIteratorInstance()->getCounter();
+
+		// Return count
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: count=%d - EXIT!', $count));
+		return $count;
 	}
 
 	/**
@@ -455,6 +510,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 */
 	public function calculateMinimumBlockLength () {
 		// Calulcate it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: CALLED!');
 		$length =
 			// Length of entry group
 			BaseBinaryFile::LENGTH_GROUP + strlen(chr(BaseBinaryFile::SEPARATOR_GROUP_HASH)) +
@@ -464,6 +520,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 			strlen(chr(BaseBinaryFile::SEPARATOR_ENTRIES));
 
 		// Return it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: length=%d - EXIT!', $length));
 		return $length;
 	}
 
@@ -590,7 +647,12 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 */
 	public function getFileSize () {
 		// Call iterator's method
-		return $this->getIteratorInstance()->getFileSize();
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: CALLED!');
+		$size = $this->getIteratorInstance()->getFileSize();
+
+		// Return size
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: size=%d - EXIT!', $size));
+		return $size;
 	}
 
 	/**
@@ -617,6 +679,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		$gapPosition = $this->getIteratorInstance()->searchNextGap(strlen($rawData));
 
 		// Gap position cannot be smaller than header length + 1
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: gapPosition=%d', $gapPosition));
 		if ($gapPosition <= $this->getIteratorInstance()->getHeaderSize()) {
 			// Improper gap position
 			throw new UnexpectedValueException(sprintf('gapPosition[%s]=%d is not larger than headerSize=%d',
diff --git a/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php b/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
index 5db1e2af..4fec8355 100644
--- a/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
+++ b/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
@@ -9,6 +9,7 @@ use Org\Mxchange\CoreFramework\Stack\File\BaseFileStack;
 use Org\Mxchange\CoreFramework\Stack\File\StackableFile;
 
 // Import SPL stuff
+use \InvalidArgumentException;
 use \SplFileInfo;
 
 /**
@@ -50,15 +51,25 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 * @param	$fileInfoInstance	An instance of a SplFileInfo class
 	 * @param	$type			Type of this stack (e.g. url_source for URL sources)
 	 * @return	$stackInstance	An instance of a StackableFile class
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 */
-	public final static function createFiFoFileStack (SplFileInfo $fileInfoInstance, $type) {
+	public final static function createFiFoFileStack (SplFileInfo $fileInfoInstance, string $type) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: fileInfoInstance[%s]=%s,type=%s - CALLED!', get_class($fileInfoInstance), $fileInfoInstance, $type));
+		if (empty($type)) {
+			// No empty type
+			throw new InvalidArgumentException('Parameter "type" is empty');
+		}
+
 		// Get new instance
 		$stackInstance = new FiFoFileStack();
 
 		// Init this stack
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: Calling stackInstance->initFileStack([%s]=%s,%s) ...', get_class($fileInfoInstance), $fileInfoInstance, $type));
 		$stackInstance->initFileStack($fileInfoInstance, $type);
 
 		// Return the prepared instance
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: stackInstance=%s - EXIT!', $stackInstance->__toString()));
 		return $stackInstance;
 	}
 
@@ -68,11 +79,26 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 * @param	$stackerName	Name of the stack
 	 * @param	$value			Value to push on it
 	 * @return	void
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	StackerFullException	If the stack is full
 	 */
 	public function pushNamed (string $stackerName, $value) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: stackerName=%s,value[]=%s - CALLED!', $stackerName, gettype($value)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		} elseif (is_object($value) || is_resource($value)) {
+			// Those types for $value are not allowed
+			throw new InvalidArgumentException(sprintf('value[]=%s is not valid', gettype($value)));
+		}
+
 		// Call the protected method
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: Calling parent::addValue(%s,%s) ...', $stackerName, gettype($value)));
 		parent::addValue($stackerName, $value);
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FIFO-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -80,17 +106,27 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of the current stack entry
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function popNamed (string $stackerName) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Get the value
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: this->getNamed(%s) ...', $stackerName));
 		$value = $this->getNamed($stackerName);
 
 		// Call the protected method
 		parent::popFirst($stackerName);
 
 		// Return the value
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -99,12 +135,25 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function getNamed (string $stackerName) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Call the protected method
-		return parent::getFirstValue($stackerName);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: parent::getFirstValue(%s) ...', $stackerName));
+		$value = parent::getFirstValue($stackerName);
+
+		// Return the value
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
+		return $value;
 	}
 
 	/**
@@ -112,9 +161,21 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 *
 	 * @param	$seekPosition	Seek position in file
 	 * @return	$status			Status of this operation
+	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 */
-	public function seek ($seekPosition) {
+	public function seek (int $seekPosition) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: seekPosition=%d - CALLED!', $seekPosition));
+		if ($seekPosition < 0) {
+			// Invalid seek position
+			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid', $seekPosition));
+		}
+
+		// @TODO Unfinished method or invoke inner iterator's method?
 		$this->partialStub('seekPosition=' . $seekPosition);
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FIFO-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -124,7 +185,12 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 */
 	public function size () {
 		// Call the iterator instance
-		return $this->getIteratorInstance()->size();
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FIFO-FILE-STACK: CALLED!');
+		$size = $this->getIteratorInstance()->size();
+
+		// Return size
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: size=%d - EXIT!', $size));
+		return $size;
 	}
 
 }
diff --git a/framework/main/classes/stacker/filo/class_FiLoStacker.php b/framework/main/classes/stacker/filo/class_FiLoStacker.php
index 78c61013..bc70761f 100644
--- a/framework/main/classes/stacker/filo/class_FiLoStacker.php
+++ b/framework/main/classes/stacker/filo/class_FiLoStacker.php
@@ -42,12 +42,14 @@ class FiLoStacker extends BaseStacker implements Stackable {
 	 */
 	public static final function createFiLoStacker () {
 		// Get a new instance
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILO-FILE-STACK: CALLED!');
 		$stackInstance = new FiLoStacker();
 
 		// Init the generic stacker
 		$stackInstance->initStack('generic');
 
 		// Return the prepared instance
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: stackInstance=%s - EXIT!', $stackInstance->__toString()));
 		return $stackInstance;
 	}
 
@@ -57,11 +59,23 @@ class FiLoStacker extends BaseStacker implements Stackable {
 	 * @param	$stackerName	Name of the stack
 	 * @param	$value			Value to push on it
 	 * @return	void
+	 * @throws	InvalidArgumentException If a parameter is invalid
 	 * @throws	StackerFullException	If the stack is full
 	 */
 	public function pushNamed (string $stackerName, $value) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: stackerName=%s,value[]=%s - CALLED!', $stackerName, gettype($value)));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Call the protected method
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: Calling parent::addValue(%s,%s) ...', $stackerName, gettype($value)));
 		parent::addValue($stackerName, $value);
+
+		// Trace message
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILO-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -69,17 +83,28 @@ class FiLoStacker extends BaseStacker implements Stackable {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of the current stack entry
+	 * @throws	InvalidArgumentException If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function popNamed (string $stackerName) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Get the value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: this->getNamed(%s) ...', $stackerName));
 		$value = $this->getNamed($stackerName);
 
 		// Call the protected method
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: parent::popLast(%s) ...', $stackerName));
 		parent::popLast($stackerName);
 
 		// Return the value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
 		return $value;
 	}
 
@@ -88,12 +113,25 @@ class FiLoStacker extends BaseStacker implements Stackable {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
+	 * @throws	InvalidArgumentException If a parameter is invalid
 	 * @throws	BadMethodCallException	If the named stacker was not found
 	 * @throws	BadMethodCallException	If the named stacker is empty
 	 */
 	public function getNamed (string $stackerName) {
+		// Validate parameter
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: stackerName=%s - CALLED!', $stackerName));
+		if (empty($stackerName)) {
+			// No empty stack name
+			throw new InvalidArgumentException('Parameter "stackerName" is empty');
+		}
+
 		// Call the protected method
-		return parent::getLastValue($stackerName);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: parent::getLastValue(%s) ...', $stackerName));
+		$value = parent::getLastValue($stackerName);
+
+		// Return the value
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILO-FILE-STACK: value[]=%s - EXIT!', gettype($value)));
+		return $value;
 	}
 
 }
-- 
2.39.5