SubsystemAction.java

/**
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 .
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and limitations under the License.
 */
package org.jboss.loom.migrators.deploymentScanner;

import org.jboss.loom.actions.AbstractStatefulAction;
import org.jboss.loom.ex.MigrationException;
import org.jboss.loom.migrators.deploymentScanner.jaxb.Subsystem;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.File;
import org.jboss.loom.utils.XmlUtils;

/**
 * User: rsearls
 */
public class SubsystemAction extends AbstractStatefulAction {

    File destFile;
    Document destDoc;
    Subsystem subsystem;
    Node rootNodeBackup = null;

    public  SubsystemAction (){
    }


    public SubsystemAction(Subsystem subsystem, File destFile, Document destDoc) {
        this.subsystem = subsystem;
        this.destFile = destFile;
        this.destDoc = destDoc;
    }

    @Override
    public void preValidate() throws MigrationException {

        if (destFile == null || !destFile.exists()){
            throw new MigrationException("Destination config file not found: " +
                    ((destFile == null)? "<name is NULL>." : destFile.getAbsolutePath()));
        } 
        if( ! destFile.canWrite() )
            throw new MigrationException("No write permissions for " + destFile.getAbsolutePath());

        // confirm required xml element
        try {
            XPath xpath = XPathFactory.newInstance().newXPath();
            String exp = "/server/profile";
            NodeList pList = (NodeList) xpath.evaluate(exp, destDoc, XPathConstants.NODESET);
            if (pList.getLength() == 0)
                throw new MigrationException("profile element not found in file: " + destDoc.getBaseURI());
        }
        catch (XPathExpressionException ex) {
            throw new MigrationException(ex);
        }
    }


    @Override
    public void perform() throws MigrationException {

        try {
            DocumentBuilder docBuilder = XmlUtils.createXmlDocumentBuilder();
            XPath xpath = XPathFactory.newInstance().newXPath();
            String exp = "/server/profile";
            NodeList pList = (NodeList) xpath.evaluate(exp, destDoc, XPathConstants.NODESET);

            if(pList.getLength() == 0)
                throw new MigrationException("profile element not found in file: " + destDoc.getBaseURI());

            JAXBContext jaxbCtx = JAXBContext.newInstance(Subsystem.class);
            Marshaller marshaller = jaxbCtx.createMarshaller();

            // transform data into DOM obj for insertion
            Document tmpDoc = docBuilder.newDocument();
            marshaller.marshal(subsystem, tmpDoc);

            Node newChild = destDoc.adoptNode( tmpDoc.getDocumentElement().cloneNode(true) );
            pList.item(0).appendChild(newChild);
            
            setState(State.DONE);
        }
        catch (JAXBException | XPathExpressionException e) {
            throw new MigrationException(e);
        }
    }


    @Override
    public void rollback() throws MigrationException {
        if (rootNodeBackup == null)
            throw new MigrationException("No backup data to rollback to.");
        Node rootNode = (Node)destDoc;
        rootNode.replaceChild(rootNodeBackup, rootNode);
        setState(State.ROLLED_BACK);
    }


    @Override
    public void postValidate() throws MigrationException {

        try {
            XPath xpath = XPathFactory.newInstance().newXPath();
            String exp = "/server/profile/subsystem/deployment-scanner";
            NodeList pList = (NodeList) xpath.evaluate(exp, destDoc, XPathConstants.NODESET);

            if (pList.getLength() == 0)
                throw new MigrationException("new deployment-scanner subsystem not successfully created");
        }
        catch (XPathExpressionException xee) {
            throw new MigrationException(xee);
        }
    }


    @Override
    public void backup() throws MigrationException {
        rootNodeBackup = ((Node)destDoc).cloneNode(true);
        setState(State.BACKED_UP);
    }


    @Override
    public void cleanBackup() {
        setState(State.FINISHED);
    }

    @Override
    public String toDescription() {
        return "Create a new deployment-scanner subsystem with a reference to the user defined AS5 deployment directory.";
    }
}