NodeService - Alfresco Content Services - 23.4 - 23.4 - Ready - Alfresco - external

Provides an API for managing nodes, such as folders and files. Nodes are the fundamental data structure in Content Services. All content that is stored is represented by a node data structure, which contains content metadata that is persisted in a database (such as PostgreSQL). The content referenced by the node is stored as a *.bin file in a content store (such as the file system, S3, encrypted or other content store).

Every node in the system is referenced by a NodeRef, which is made up of the content store protocol, the content store name, and the Universal Unique Identifier (UUID) of the content, for example: workspace://SpacesStore/ccb906ba-a768-4ccb-8b26-515119e1efdc. Generally nodes are of two main types, a file node (cm:content), or a folder node (cm:folder). Folders can contain child nodes. Note that each content store will have a root node, and all other nodes in the store will be children of the root node.

The NodeService provides an extensive API for managing nodes. Functionality includes:

• Adding aspects, children, properties, associations
• Getting aspects, children, properties, associations
• Removing aspects, children, properties, associations
• Creating and deleting stores
• Creating and deleting nodes
• Checking for existence of a node
• Get available content stores
• Moving nodes

The NodeService makes extensive use of NodeRefs to reference the node of interest.

Note that for creating folders and files you should also have a look at FileFolderService as it is an abstraction of the NodeService service that makes it a bit easier to work with folders and files with the cost of being less flexible.

Creating a file node:

NodeRef parentFolderNodeRef = serviceRegistry.getNodeLocatorService().getNode(CompanyHomeNodeLocator.NAME, null, null);

// Create file node metadata
QName associationType = ContentModel.ASSOC_CONTAINS;
QName associationQName = QName.createQName(NamespaceService.CONTENT_MODEL_1_0_URI,
        QName.createValidLocalName(filename));
Map<QName, Serializable> nodeProperties = new HashMap<QName, Serializable>();
nodeProperties.put(ContentModel.PROP_NAME, filename);
ChildAssociationRef parentChildAssocRef = serviceRegistry.getNodeService().createNode(
        parentFolderNodeRef, associationType, associationQName, ContractType.QNAME, nodeProperties);
NodeRef newFileNodeRef = parentChildAssocRef.getChildRef();

// Set text content for file node
boolean updateContentPropertyAutomatically = true;
ContentWriter writer = serviceRegistry.getContentService().getWriter(
        newFileNodeRef, ContentModel.PROP_CONTENT, updateContentPropertyAutomatically);
writer.setMimetype(MimetypeMap.MIMETYPE_TEXT_PLAIN);
writer.setEncoding("UTF-8");
writer.putContent(someText);

Creating a folder node:

privatevoidcreateFolder(NodeRef rootRef){
    String folderName = "SampleFolder";
    NodeRef parentFolderNodeRef = rootRef;

    // Create folder node 
    QName associationType = ContentModel.ASSOC_CONTAINS;
    QName associationQName = QName.createQName(NamespaceService.CONTENT_MODEL_1_0_URI,
            QName.createValidLocalName(folderName));
    QName nodeType = ContentModel.TYPE_FOLDER;
    Map<QName, Serializable> nodeProperties = new HashMap<QName, Serializable>();
    nodeProperties.put(ContentModel.PROP_NAME, folderName);
    ChildAssociationRef parentChildAssocRef = serviceRegistry.getNodeService().createNode(
            parentFolderNodeRef, associationType, associationQName, nodeType, nodeProperties);
    NodeRef newFolderNodeRef = parentChildAssocRef.getChildRef();

}

Add an aspect to a node:

NodeRef someNodeRef = ...
Map<QName, Serializable> aspectProperties = new HashMap<QName, Serializable>();
aspectProperties.put(ContentModel.PROP_TITLE, "A title");
aspectProperties.put(ContentModel.PROP_DESCRIPTION, "A description");
serviceRegistry.getNodeService().addAspect(someNodeRef, ContentModel.ASPECT_TITLED, aspectProperties);

Getting a NodeRef from the node path:

StoreRef storeRef = new StoreRef(StoreRef.PROTOCOL_WORKSPACE, "SpacesStore");
ResultSet rs = serviceRegistry.getSearchService().query(storeRef, SearchService.LANGUAGE_LUCENE, 
        "PATH:\"/app:company_home/app:user_homes/sys:boris/cm:mypics\"");
NodeRef companyHomeNodeRef = null;
try {
    if (rs.length() == 0) {
        thrownew AlfrescoRuntimeException("Didn't find Company Home");
    }

    companyHomeNodeRef = rs.getNodeRef(0);
} finally {
    rs.close();
}

Getting a file name from a NodeRef:

String fileName = (String) serviceRegistry.getNodeService().getProperty(nodeRef, ContentModel.PROP_NAME);

Reading a node property. The property may come from an aspect or not. You will probably want to cast to the appropriate type:

QName PROP_QNAME_MY_PROPERTY = QName.createQName("custom.model", "myProperty");
Object value = serviceRegistry.getNodeService().getProperty(nodeRef, PROP_QNAME_MY_PROPERTY);

Updating a node property. The property may come from an aspect or not:

QName PROP_QNAME_MY_PROPERTY = QName.createQName("custom.model", "myProperty");
serviceRegistry.getNodeService().setProperty(nodeRef, PROP_QNAME_MY_PROPERTY, value);

Getting the parent of a NodeRef:

ChildAssociationRef childAssociationRef = serviceRegistry.getNodeService().getPrimaryParent(nodeRef);
NodeRef parentFolderNodeRef = childAssociationRef.getParentRef();

Adding an aspect to a node. Supposing the “MyAspect” aspect defines a “myProperty” property in the “custom.model” namespace:

QName CUSTOM_ASPECT_QNAME = QName.createQName("custom.model", "MyAspect");
QName PROP_QNAME_MY_PROPERTY = QName.createQName("custom.model", "myProperty");
Map<QName,Serializable> aspectValues = new HashMap<QName,Serializable>();
aspectValues.put(PROP_QNAME_MY_PROPERTY, value);
serviceRegistry.getNodeService().addAspect(nodeRef, CUSTOM_ASPECT_QNAME, aspectValues);

Checking whether a node has a given aspect:

QName CUSTOM_ASPECT_QNAME = QName.createQName("custom.model", "MyAspect");
boolean hasAspect = serviceRegistry.getNodeService().hasAspect(node, CUSTOM_ASPECT_QNAME);

Looping through children of a NodeRef:

List<ChildAssociationRef> children = serviceRegistry.getNodeService().getChildAssocs(companyHome);
for (ChildAssociationRef childAssoc : children) {
    NodeRef childNodeRef = childAssoc.getChildRef();
    // Use childNodeRef here.
}

Creating a parent-child association between two existing NodeRef:

QName PROP_QNAME_MY_CHILD_ASSOCIATION = QName.createQName("custom.model", "myChildAssociation");
serviceRegistry.getNodeService().addChild(parentNodeRef, childNodeRef, PROP_QNAME_MY_CHILD_ASSOCIATION, PROP_QNAME_MY_CHILD_ASSOCIATION);

Creating a peer-2-peer association between two existing NodeRef:

QName PROP_QNAME_MY_ASSOCIATION = QName.createQName("custom.model", "myAssociation");
serviceRegistry.getNodeService().createAssociation(sourceNodeRef, targetNodeRef, PROP_QNAME_MY_ASSOCIATION);

Setting the content type of a node:

QName PROP_QNAME_MY_TYPE = QName.createQName("custom.model", "myType");
serviceRegistry.getNodeService().setType(finalOriginal, MY_TYPE);

Getting the MIME type of a node:

ContentData contentData = (ContentData) serviceRegistry.getNodeService().getProperty(nodeRef, ContentModel.PROP_CONTENT);
String originalMimeType = contentData.getMimetype();

Adding a category to a node:

ArrayList<NodeRef> categories = new ArrayList<NodeRef>(1);
categories.add(categoryNode);
if (!serviceRegistry.getNodeService().hasAspect(targetNode, ContentModel.ASPECT_GEN_CLASSIFIABLE) {
    HashMap<QName, Serializable> props = new HashMap<QName, Serializable>();
    props.put(ContentModel.PROP_CATEGORIES, categories);
    serviceRegistry.getNodeService().addAspect(targetNode, ContentModel.ASPECT_GEN_CLASSIFIABLE, props);
} else {
    serviceRegistry.getNodeService().setProperty(targetNode, ContentModel.PROP_CATEGORIES, categories);
}

Getting the categories of a node:

List<NodeRef> categories = (List<NodeRef>) serviceRegistry.getNodeService().getProperty(nodeRef, ContentModel.PROP_CATEGORIES);

Deleting a node for real (not recycle bin):

serviceRegistry.getNodeService().addAspect(nodeRef, ContentModel.ASPECT_TEMPORARY, null);
serviceRegistry.getNodeService().deleteNode(nodeRef);

See also Content Stores.