PHP trait that gives classes property accessor functionality.

Accessors.php

<?php
use LogicException;
use BadMethodCallException;

trait Accessors
{
    /**
     * Gets the value of a property.
     *
     * @param string $name
     * The name of the property.
     *
     * @return mixed
     * The value of the property.
     *
     * @throws LogicException
     * Thrown if the property is write-only or does not exist.
     */
    final public function __get($name)
    {
        // check if the property has a getter
        if (method_exists($this, "get_$name"))
        {
            // call the getter
            return call_user_func(array($this, "get_$name"));
        }

        // check if the property has a setter
        else if (method_exists($this, "set_$name"))
        {
            throw new LogicException("Member variable '$name' is write only.");
        }

        // non-existent property
        else
        {
            throw new LogicException("Member variable '$name' does not exist.");
        }
    }

    /**
     * Sets the value of a property.
     *
     * @param string $name
     * The name of the property.
     *
     * @param mixed $value
     * The value to set the property to.
     *
     * @return void
     *
     * @throws LogicException
     * Thrown if the property is read only or does not exist.
     */
    final public function __set($name, $value)
    {
        // check if the property has a setter
        if (method_exists($this, "set_$name"))
        {
            // set value
            call_user_func(array($this, "set_$name"), $value);
        }

        // property is read only
        else if (method_exists($this, "get_$name"))
        {
            throw new LogicException("Member variable '$name' is read only.");
        }

        // non-existent property
        else
        {
            throw new LogicException("Member variable '$name' does not exist.");
        }
    }

    /**
     * Checks if a property is set.
     *
     * @param string $name
     * The name of the property.
     *
     * @return bool
     * True if the property is set, otherwise false.
     */
    final public function __isset($name)
    {
        // check if the property has a getter
        if (method_exists($this, "get_$name"))
        {
            return $this->__get($name) !== null;
        }

        return false;
    }

    /**
     * Unsets a property by setting its value to null.
     *
     * @param string $name
     * The name of the property.
     *
     * @return void
     */
    final public function __unset($name)
    {
        $this->__set($name, null);
    }

    /**
     * Handles method calls that do not point to a function.
     *
     * Also fixes PHP bug where invoking a callable property causes an exception.
     *
     * @param string $name
     * The name of the invalid method.
     *
     * @param mixed[] $args
     * Arguments passed to the method.
     *
     * @return mixed
     * The return value of the method called.
     *
     * @throws BadMethodCallException
     * Thrown if a property isn't callable or the method doesn't exist.
     */
    final public function __call($name, $args)
    {
        // trying to invoke a property
        if (property_exists($this, $name) || method_exists($this, "get_$name"))
        {
            $value = $this->$name;
            
            // fix for invoking callable objects as properties
            if (is_object($value) && method_exists($value, '__invoke'))
            {
                return call_user_func_array(array($value, '__invoke'), $args);
            }

            // a callable name or function
            else if (is_callable($value))
            {
                return call_user_func_array($value, $args);
            }

            // the property isn't callable
            else
            {
                throw new BadMethodCallException("The property '$name' is not callable.");
            }
        }

        // method doesn't exist
        throw new BadMethodCallException("Method '$name' does not exist.");
    }
}