public function onBeforeWrite()
{
$changedFields = $this->owner->getChangedFields(false, 1);
if (array_key_exists("DocumentTags", $changedFields)) {
$currentTags = explode(',', $this->owner->getField('DocumentTags'));
$oldTags = DMSTag::get()->innerJoin("DMSDocument_Tags", "\"DMSDocument_Tags\".\"DMSTagID\" = \"DMSTag\".\"ID\" AND \"DMSDocument_Tags\".\"DMSDocumentID\" = " . $this->owner->ID)->column();
// delete the tags
foreach (array_diff($oldTags, $currentTags) as $idTag) {
$tag = DMSTag::get()->byID($idTag);
if ($tag) {
$this->owner->removeTag($tag->Category, $tag->Value ? $tag->Value : null);
}
}
// add the tags
foreach (array_diff($currentTags, $oldTags) as $idTag) {
$tag = DMSTag::get()->byID($idTag);
if ($tag) {
$tag->Documents()->add($this->owner);
}
}
}
}
/**
* Adds a metadata tag to the Document. The tag has a category and a value.
* Each category can have multiple values by default. So: addTag("fruit","banana") addTag("fruit", "apple") will add two items.
* However, if the third parameter $multiValue is set to 'false', then all updates to a category only ever update a single value. So:
* addTag("fruit","banana") addTag("fruit", "apple") would result in a single metadata tag: fruit->apple.
* Can could be implemented as a key/value store table (although it is more like category/value, because the
* same category can occur multiple times)
* @param $category String of a metadata category to add (required)
* @param $value String of a metadata value to add (required)
* @param bool $multiValue Boolean that determines if the category is multi-value or single-value (optional)
* @return null
*/
function addTag($category, $value, $multiValue = true)
{
if ($multiValue) {
//check for a duplicate tag, don't add the duplicate
$currentTag = $this->Tags()->filter(array('Category' => $category, 'Value' => $value));
if ($currentTag->Count() == 0) {
//multi value tag
$tag = new DMSTag();
$tag->Category = $category;
$tag->Value = $value;
$tag->MultiValue = true;
$tag->write();
$tag->Documents()->add($this);
} else {
//add the relation between the tag and document
foreach ($currentTag as $tagObj) {
$tagObj->Documents()->add($this);
}
}
} else {
//single value tag
$currentTag = $this->Tags()->filter(array('Category' => $category));
$tag = null;
if ($currentTag->Count() == 0) {
//create the single-value tag
$tag = new DMSTag();
$tag->Category = $category;
$tag->Value = $value;
$tag->MultiValue = false;
$tag->write();
} else {
//update the single value tag
$tag = $currentTag->first();
$tag->Value = $value;
$tag->MultiValue = false;
$tag->write();
}
//regardless of whether we created a new tag or are just updating an existing one, add the relation
$tag->Documents()->add($this);
}
}