com.paypal.butterfly.extensions.api.Extension Maven / Gradle / Ivy
package com.paypal.butterfly.extensions.api;
import com.paypal.butterfly.extensions.api.exception.TemplateResolutionException;
import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* A Butterfly third-party extension. It provides custom
* transformation templates and validations
*
* @author facarvalho
*/
public abstract class Extension {
private static final Logger logger = LoggerFactory.getLogger(Extension.class);
private List> templateClasses = new ArrayList<>();
/**
* Adds a new transformation template class to the set
*
* @param templateClass the transformation template class to be added to the extension
*
* @return this extension
*/
protected final E add(Class templateClass) {
templateClasses.add(templateClass);
return (E) this;
}
/**
* Returns the extension description
*
* @return the extension description
*/
public abstract String getDescription();
/**
* Returns the extension version
*
* @return the extension version
*/
public abstract String getVersion();
/**
* Returns a read-only set containing all transformation template classes
*
* @return a read-only set containing all transformation template classes
*/
public final List> getTemplateClasses() {
return Collections.unmodifiableList(templateClasses);
}
/**
* Butterfly might be able to automatically identify, based on the application
* content, the most applicable transformation template to transform it.
* If no template applies to the application content, a {@link TemplateResolutionException}
* is thrown explaining the reason why no template could be chosen.
*
* @param applicationFolder the folder where the code of the application to be transformed is
* @return the chosen transformation template
* @throws TemplateResolutionException if no template applies
*/
public Class automaticResolution(File applicationFolder) throws TemplateResolutionException {
throw new TemplateResolutionException("No transformation template could be resolved");
}
/**
* This is a convenience method in case the Extension subclass wants to implement its
* {@link #automaticResolution(File)} method based on one or more Maven pom files
*
* @param folder the folder where the pom.xml file would be
* @return the Model object related to the pom.xml file under {@code folder}, or null, if that file does
* not exist, or any error happens when trying to read and parse it
*/
protected Model getRootPomFile(File folder) {
File pomFile = null;
FileInputStream fileInputStream = null;
Model model = null;
try {
MavenXpp3Reader reader = new MavenXpp3Reader();
pomFile = new File(folder, "pom.xml");
if (!pomFile.exists()) {
if (logger.isDebugEnabled()) {
logger.debug("This application does not have a pom.xml file on its root folder");
}
return null;
}
fileInputStream = new FileInputStream(pomFile);
model = reader.read(fileInputStream);
} catch (Exception e) {
if (logger.isDebugEnabled()) {
logger.error("Error happened when trying to read and parse pom.xml file " + pomFile, e);
}
} finally {
if (fileInputStream != null) try {
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return model;
}
@Override
public final String toString() {
return getClass().getName();
}
}