info.magnolia.module.delta
Class NodeVisitorTask

java.lang.Object
  info.magnolia.module.delta.AbstractTask
      info.magnolia.module.delta.AbstractRepositoryTask
          info.magnolia.module.delta.NodeVisitorTask

All Implemented Interfaces:

Task

public abstract class NodeVisitorTask
extends AbstractRepositoryTask

The NodeVisitorTask helps traversing a repository, match nodes and execute changes on them.

This is intended to replace QueryTask for most cases, since query results may not account for pending changes in the session (e.g. coming from earlier deltas).

Field Summary

Fields inherited from class info.magnolia.module.delta.AbstractTask

DO_NOTHING, log

Constructor Summary

NodeVisitorTask(String name, String description, String workspace, String absPath)

Method Summary

protected void	doExecute(InstallContext installContext)
protected org.apache.jackrabbit.commons.predicate.Predicate	getFilteringPredicate() Override this method to specify a Predicate where we should stop visiting the hierarchy, e.g.
protected abstract boolean	nodeMatches(javax.jcr.Node node) Implement this method to define which nodes should subsequently be operated upon.
protected abstract void	operateOnNode(InstallContext installContext, javax.jcr.Node node) Implement this method to apply changes to each of the nodes that are matched by nodeMatches(Node).

Methods inherited from class info.magnolia.module.delta.AbstractRepositoryTask

execute

Methods inherited from class info.magnolia.module.delta.AbstractTask

getDescription, getName, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NodeVisitorTask

public NodeVisitorTask(String name,
                       String description,
                       String workspace,
                       String absPath)

Method Detail

doExecute

protected void doExecute(InstallContext installContext)
                  throws javax.jcr.RepositoryException,
                         TaskExecutionException

Specified by:

doExecute in class AbstractRepositoryTask

Throws:

javax.jcr.RepositoryException

TaskExecutionException

nodeMatches

protected abstract boolean nodeMatches(javax.jcr.Node node)

Implement this method to define which nodes should subsequently be operated upon.

This will be called for every visited node in that task, and serves a similar purpose as a JCR query statement.

Parameters:

node - the JCR node that is currently being visited

Returns:

true if the node should be operated upon, false otherwise

See Also:

operateOnNode(InstallContext, Node)

operateOnNode

protected abstract void operateOnNode(InstallContext installContext,
                                      javax.jcr.Node node)

Implement this method to apply changes to each of the nodes that are matched by nodeMatches(Node).

This is typically where the update logic goes, in a similar fashion as the QueryTask.

Parameters:

installContext - the current install context

node - the JCR node that should be operated upon

See Also:

QueryTask#operateOnNode(InstallContext, Node)}

getFilteringPredicate

protected org.apache.jackrabbit.commons.predicate.Predicate getFilteringPredicate()

Override this method to specify a Predicate where we should stop visiting the hierarchy, e.g. to restrict node-types.

Mind that whatever the predicate, the starting node is always visited by NodeUtil, even if it doesn't match the predicate.

Returns:

by default, the constant predicate that returns true for all objects.