Revert changes to documentation

Instead of altering docs for the v2 series, new docs must be created and amended for the v3 series

Signed-off-by: George Steel <[email protected]>

docs/book/file.md

@@ -9,6 +9,50 @@ performing file operations such as renaming.
 > *or* a `$_FILES` array as the supplied argument. When a `$_FILES` array is
 > passed in, the `tmp_name` is used for the file path.
 
+## Encrypt and Decrypt
+
+These filters allow encrypting and decrypting file contents, and are derived
+from the `Laminas\Filter\Encrypt` and `Laminas\Filter\Decrypt` filters. Only file reading and
+writing operations are performed by the filer; encryption and decryption operations
+are performed by the parent classes.
+
+Usage:
+
+```php
+use Laminas\Filter\File\Encrypt as EncryptFileFilter;
+use Laminas\Http\PhpEnvironment\Request;
+
+$request = new Request();
+$files   = $request->getFiles();
+// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'
+
+$filter = new EncryptFileFilter([
+    'adapter' => 'BlockCipher',
+    'key' => '--our-super-secret-key--',
+]);
+$filter->filter($files['my-upload']);
+```
+
+In the above example, we pass options to our constructor in order to configure
+the filter. We could instead use use setter methods to inject these options:
+
+```php
+use Laminas\Filter\File\Encrypt as EncryptFileFilter;
+use Laminas\Http\PhpEnvironment\Request;
+
+$request = new Request();
+$files   = $request->getFiles();
+// i.e. $files['my-upload']['tmp_name'] === '/tmp/php5Wx0aJ'
+
+$filter = new EncryptFileFilter();
+$filter->setAdapter('BlockCipher');
+$filter->setKey('--our-super-secret-key--');
+$filter->filter($files['my-upload']);
+```
+
+Check the [Encrypt and Decrypt filter documentation](/laminas-filter/standard-filters/#encrypt-and-decrypt)
+for more information about options and adapters.
+
 ## Lowercase
 
 `Laminas\Filter\File\Lowercase` can be used to convert all file contents to

docs/book/intro.md

@@ -53,6 +53,54 @@ echo $strtolower('I LOVE Laminas!'); // i love laminas!
 $laminaslove = $strtolower('I LOVE Laminas!');
 ```
 
+## Using the StaticFilter
+
+If it is inconvenient to load a given filter class and create an instance of the
+filter, you can use `StaticFilter` with its `execute()` method as an alternative
+invocation style. The first argument of this method is a data input value, that
+you would pass to the `filter()` method. The second argument is a string, which
+corresponds to the basename of the filter class, relative to the `Laminas\Filter`
+namespace. The `execute()` method automatically loads the class, creates an
+instance, and applies the `filter()` method to the data input.
+
+```php
+echo StaticFilter::execute('&', 'HtmlEntities');
+```
+
+You can also pass an array of constructor arguments, if they are needed for the
+filter class:
+
+```php
+echo StaticFilter::execute(
+    '"',
+    'HtmlEntities',
+    ['quotestyle' => ENT_QUOTES]
+);
+```
+
+The static usage can be convenient for invoking a filter ad hoc, but if you have
+the need to run a filter for multiple inputs, it’s more efficient to follow the
+first example above, creating an instance of the filter object and calling its
+`filter()` method.
+
+Also, the `FilterChain` class allows you to instantiate and run multiple filter
+and validator classes on demand to process sets of input data. See the
+[FilterChain](filter-chains.md) chapter for more details.
+
+You can set and receive the `FilterPluginManager` for the `StaticFilter` to
+amend the standard filter classes.
+
+```php
+$pluginManager = StaticFilter::getPluginManager()->setInvokableClass(
+    'myNewFilter',
+    'MyCustom\Filter\MyNewFilter'
+);
+
+StaticFilter::setPluginManager(new MyFilterPluginManager());
+```
+
+This is useful when adding custom filters to be used by the `StaticFilter`.
+
 ## Double filtering
 
 When using two filters in succession, you have to keep in mind that it is