Multiple file merger (PHP)

merger.php

<?php
	class Merger {
		private static $mergePending = array();
		private static $mergeStats = array();

	   /* public static function mergeFiles
		* @var 	mixed 	$filesArray			array of names of files (including directories) to merge from
		* @var 	string 	$destinationFile	name of file to save merged files to
		* @var 	mixed 	$splitterFunction	anonymous function providing splitting of each file, in: string, out: array of items
		* @var 	mixed 	$joinerFunction		anonymous function providing merging all files with delimiter, in: array of items, out: string
		* @return 	mixed 	stats for current merge operation
		*/
		public static function mergeFiles( $filesArray, $destinationFile, $splitterFunction, $joinerFunction ) {
			foreach ( $filesArray as $ID => $file ) {
				$fileContents = file_get_contents( $file );
				$nesessaryParts = $splitterFunction( $fileContents );

				$newPartCounter = 0;
				foreach ( $nesessaryParts as $part ) {
					if( !in_array( $part, self::$mergePending ) ) {
						self::$mergePending[] = $part;
						$newPartCounter ++;
					}
				}

				self::$mergeStats[] = "Added $newPartCounter parts for merging from $file";
			}

			self::$mergeStats[] = "Total parts count is " . count( self::$mergePending );
			$destinationFileContents = $joinerFunction( self::$mergePending );

			$fileWrite = fopen( $destinationFile, 'w+' );
			fwrite( $fileWrite, $destinationFileContents );

			return self::$mergeStats;
		}
	}


	// Example
	$details = Merger::mergeFiles(
		array( '01.html', '02.html', '03.html' ),
		'_test.spf',
		function( $file ) { 
			$replaces = array();
			for( $count = 1; $count <= 9; $count ++ ) {
				$replaces[ "value=$count" ] = '';
			}
			return explode( "<hr/>", strtr( $file, $replaces ) ); 
		},
		function( $array ) { return implode( $array, "<hr/>" ); }
	);

	var_dump( $details );