ObjectFactory.php

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<?php
class ObjectFactory {
 
    public static function getObjectFromSpec( $spec ) {
        $args = isset( $spec['args'] ) ? $spec['args'] : [];
        $expandArgs = !isset( $spec['closure_expansion'] ) ||
            $spec['closure_expansion'] === true;
 
        if ( $expandArgs ) {
            $args = static::expandClosures( $args );
        }
 
        if ( isset( $spec['class'] ) ) {
            $clazz = $spec['class'];
            if ( !$args ) {
                $obj = new $clazz();
            } else {
                $obj = static::constructClassInstance( $clazz, $args );
            }
        } elseif ( isset( $spec['factory'] ) ) {
            $obj = call_user_func_array( $spec['factory'], $args );
        } else {
            throw new InvalidArgumentException(
                'Provided specification lacks both factory and class parameters.'
            );
        }
 
        if ( isset( $spec['calls'] ) && is_array( $spec['calls'] ) ) {
            // Call additional methods on the newly created object
            foreach ( $spec['calls'] as $method => $margs ) {
                if ( $expandArgs ) {
                    $margs = static::expandClosures( $margs );
                }
                call_user_func_array( [ $obj, $method ], $margs );
            }
        }
 
        return $obj;
    }
 
    protected static function expandClosures( $list ) {
        return array_map( function ( $value ) {
            if ( is_object( $value ) && $value instanceof Closure ) {
                // If $value is a Closure, call it.
                return $value();
            } else {
                return $value;
            }
        }, $list );
    }
 
    public static function constructClassInstance( $clazz, $args ) {
        // $args should be a non-associative array; show nice error if that's not the case
        if ( $args && array_keys( $args ) !== range( 0, count( $args ) - 1 ) ) {
            throw new InvalidArgumentException( __METHOD__ . ': $args cannot be an associative array' );
        }
 
        // TODO: when PHP min version supported is >=5.6.0 replace this
        // with `return new $clazz( ... $args );`.
        $obj = null;
        switch ( count( $args ) ) {
            case 0:
                $obj = new $clazz();
                break;
            case 1:
                $obj = new $clazz( $args[0] );
                break;
            case 2:
                $obj = new $clazz( $args[0], $args[1] );
                break;
            case 3:
                $obj = new $clazz( $args[0], $args[1], $args[2] );
                break;
            case 4:
                $obj = new $clazz( $args[0], $args[1], $args[2], $args[3] );
                break;
            case 5:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4]
                );
                break;
            case 6:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4],
                    $args[5]
                );
                break;
            case 7:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4],
                    $args[5], $args[6]
                );
                break;
            case 8:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4],
                    $args[5], $args[6], $args[7]
                );
                break;
            case 9:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4],
                    $args[5], $args[6], $args[7], $args[8]
                );
                break;
            case 10:
                $obj = new $clazz(
                    $args[0], $args[1], $args[2], $args[3], $args[4],
                    $args[5], $args[6], $args[7], $args[8], $args[9]
                );
                break;
            default:
                // Fall back to using ReflectionClass and curse the developer
                // who decided that 11+ args was a reasonable method
                // signature.
                $ref = new ReflectionClass( $clazz );
                $obj = $ref->newInstanceArgs( $args );
        }
        return $obj;
    }
}