Merge pull request #28 from Icinga/introduce-base-filter

Introduce trait `ipl\Stdlib\BaseFilter`

src/BaseFilter.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace ipl\Stdlib;
+
+use ipl\Stdlib\Filter\Rule;
+
+trait BaseFilter
+{
+    /** @var Rule Base filter */
+    private $baseFilter;
+
+    /**
+     * Get whether a base filter has been set
+     *
+     * @return bool
+     */
+    public function hasBaseFilter(): bool
+    {
+        return $this->baseFilter !== null;
+    }
+
+    /**
+     * Get the base filter
+     *
+     * @return ?Rule
+     */
+    public function getBaseFilter()
+    {
+        return $this->baseFilter;
+    }
+
+    /**
+     * Set the base filter
+     *
+     * @param Rule $baseFilter
+     *
+     * @return $this
+     */
+    public function setBaseFilter(Rule $baseFilter = null): self
+    {
+        $this->baseFilter = $baseFilter;
+
+        return $this;
+    }
+}