com.cloudera.cdk.maven.plugins.WorkflowXmlWriter.java Source code

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Here is the source code for com.cloudera.cdk.maven.plugins.WorkflowXmlWriter.java

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/**
 * Copyright 2013 Cloudera Inc.
 *
 * 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 com.cloudera.cdk.maven.plugins;

import com.google.common.base.Joiner;
import java.io.File;
import java.io.IOException;
import java.io.Writer;
import java.util.Properties;
import org.apache.commons.io.IOUtils;
import org.apache.maven.plugin.MojoExecutionException;
import org.codehaus.plexus.util.WriterFactory;
import org.codehaus.plexus.util.xml.PrettyPrintXMLWriter;
import org.codehaus.plexus.util.xml.XMLWriter;

class WorkflowXmlWriter {

    private final String encoding;

    private static final String WORKFLOW_ELEMENT = "workflow-app";

    WorkflowXmlWriter(String encoding) {
        this.encoding = encoding;
    }

    protected Writer initializeWriter(final File destinationFile) throws MojoExecutionException {
        try {
            return WriterFactory.newXmlWriter(destinationFile);
        } catch (IOException e) {
            throw new MojoExecutionException(
                    "Exception while opening file[" + destinationFile.getAbsolutePath() + "]", e);
        }
    }

    protected XMLWriter initializeXmlWriter(final Writer writer, final String docType) {
        return new PrettyPrintXMLWriter(writer, encoding, docType);
    }

    protected void write(Workflow workflow) throws MojoExecutionException {
        Writer w = initializeWriter(workflow.getDestinationFile());
        XMLWriter writer = initializeRootElement(w, workflow.getSchemaVersion(), workflow.getName());

        appendStart(writer);
        appendJavaAction(writer, workflow);
        appendKill(writer);
        appendEnd(writer);

        writer.endElement();
        close(w);
    }

    private XMLWriter initializeRootElement(Writer w, String schemaVersion, String workflowName) {
        XMLWriter writer = initializeXmlWriter(w, null);
        writer.startElement(WORKFLOW_ELEMENT);
        writer.addAttribute("xmlns", "uri:oozie:workflow:" + schemaVersion);
        writer.addAttribute("name", workflowName);
        return writer;
    }

    private void appendStart(XMLWriter writer) {
        writer.startElement("start");
        writer.addAttribute("to", "java-node");
        writer.endElement();
    }

    private void appendJavaAction(XMLWriter writer, Workflow workflow) throws MojoExecutionException {
        Properties hadoopConfiguration = workflow.getHadoopConfiguration();

        writer.startElement("action");
        writer.addAttribute("name", "java-node");

        writer.startElement("java");
        doWriteElement(writer, "job-tracker", "${" + AbstractAppMojo.JOBTRACKER_PROPERTY + "}");
        doWriteElement(writer, "name-node", "${" + AbstractAppMojo.NAMENODE_PROPERTY + "}");
        doWriteElement(writer, "main-class", workflow.getToolClass());
        for (String key : hadoopConfiguration.stringPropertyNames()) {
            String value = hadoopConfiguration.getProperty(key);
            doWriteElement(writer, "arg", "-D");
            doWriteElement(writer, "arg", key + "=" + value);
        }
        if (!workflow.getLibJars().isEmpty()) {
            doWriteElement(writer, "arg", "-libjars");
            doWriteElement(writer, "arg", Joiner.on(',').join(workflow.getLibJars()));
        }
        String[] args = workflow.getArgs();
        if (args != null) {
            for (String arg : args) {
                doWriteElement(writer, "arg", arg);
            }
        }
        writer.endElement();

        doWriteElement(writer, "ok", "to", "end");
        doWriteElement(writer, "error", "to", "fail");

        writer.endElement();
    }

    private void appendKill(XMLWriter writer) {
        writer.startElement("kill");
        writer.addAttribute("name", "fail");
        doWriteElement(writer, "message", "Java failed, error message[${wf:errorMessage(wf:lastErrorNode())}]");
        writer.endElement();
    }

    private void appendEnd(XMLWriter writer) {
        writer.startElement("end");
        writer.addAttribute("name", "end");
        writer.endElement();
    }

    private void doWriteElement(XMLWriter writer, String element, String attributeName, String attributeValue) {
        writer.startElement(element);
        writer.addAttribute(attributeName, attributeValue);
        writer.endElement();
    }

    private void doWriteElement(XMLWriter writer, String element, String text) {
        writer.startElement(element);
        writer.writeText(text);
        writer.endElement();
    }

    protected void close(Writer closeable) {
        IOUtils.closeQuietly(closeable);
    }
}