scriptella.configuration.ConfigurationFactory Maven / Gradle / Ivy
/*
* Copyright 2006-2012 The Scriptella Project Team.
*
* 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 scriptella.configuration;
import org.w3c.dom.Document;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXParseException;
import scriptella.expression.PropertiesSubstitutor;
import scriptella.spi.ParametersCallback;
import scriptella.spi.support.HierarchicalParametersCallback;
import scriptella.spi.support.MapParametersCallback;
import scriptella.spi.support.NullParametersCallback;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Map;
import java.util.logging.Logger;
/**
* Factory class for ETL {@link ConfigurationEl configuration} files.
*
* @author Fyodor Kupolov
* @version 1.0
*/
public class ConfigurationFactory {
private static final Logger LOG = Logger.getLogger(ConfigurationFactory.class.getName());
private static final DocumentBuilderFactory DBF = DocumentBuilderFactory.newInstance();
private static final String DTD_NAME = "etl.dtd";
private static final String RES_PATH = "/scriptella/dtd/" + DTD_NAME;
private URL resourceURL;
private ParametersCallback externalParameters;
static {
setValidating(true);
}
/**
* Sets validation option.
*
* @param validating true if XML file validation should be performed.
*/
public static void setValidating(boolean validating) {
DBF.setValidating(validating);
}
public ConfigurationFactory() {
}
public URL getResourceURL() {
return resourceURL;
}
public void setResourceURL(final URL resourceURL) {
this.resourceURL = resourceURL;
}
/**
* Sets additional properties.
* External properties takes precedence over properties specified
* in ETL <properties> element.
*
Intended for integration with other systems like ant.
*
* @param externalProperties external properties. Nulls allowed.
*/
public void setExternalParameters(final Map externalProperties) {
setExternalParameters(externalProperties == null ? null : new MapParametersCallback(externalProperties));
}
/**
* Sets additional parameters.
* These parameters take precedence over properties specified in the <properties> section of an ETL file.
*
Intended for integration with other systems like ant.
*
* @param externalParameters external parameters.
*/
public void setExternalParameters(final ParametersCallback externalParameters) {
this.externalParameters = externalParameters;
}
/**
* Parses XML file and creates a configuration based on a specified parameters.
*
* @return configuration element.
*/
public ConfigurationEl createConfiguration() {
if (resourceURL == null) {
throw new ConfigurationException("Configuration URL is required");
}
try {
DocumentBuilder db = DBF.newDocumentBuilder();
db.setEntityResolver(ETL_ENTITY_RESOLVER);
db.setErrorHandler(ETL_ERROR_HANDLER);
final InputSource inputSource = new InputSource(resourceURL.toString());
final Document document = db.parse(inputSource);
HierarchicalParametersCallback params = new HierarchicalParametersCallback(
externalParameters == null ? NullParametersCallback.INSTANCE : externalParameters, null);
PropertiesSubstitutor ps = new PropertiesSubstitutor(params);
return new ConfigurationEl(new XmlElement(
document.getDocumentElement(), resourceURL, ps), params);
} catch (IOException e) {
throw new ConfigurationException("Unable to load document: " + e, e);
} catch (Exception e) {
throw new ConfigurationException("Unable to parse document: " + e, e);
}
}
//XML-related stuff - resolver+error handler
private static final EntityResolver ETL_ENTITY_RESOLVER = new EntityResolver() {
public InputSource resolveEntity(final String publicId, final String systemId) {
if (systemId != null && systemId.trim().endsWith(DTD_NAME)) {
InputStream stream = ConfigurationFactory.class.getResourceAsStream(RES_PATH);
if (stream == null) { //This may happen only in IDE if *.dtd are not copied during compile
throw new IllegalStateException("Scriptella required DTD resource " + RES_PATH +
" not found on classpath. Please check scriptella.jar and its content.");
}
return new InputSource(stream);
}
return null;
}
};
private static final ErrorHandler ETL_ERROR_HANDLER = new ErrorHandler() {
public void warning(final SAXParseException exception) {
LOG.warning(messageFor(exception));
}
public void error(final SAXParseException exception) {
LOG.warning(messageFor(exception));
}
private String messageFor(final SAXParseException exception) {
StringBuilder sb = new StringBuilder(32);
sb.append("XML configuration warning in ");
final String sid = exception.getSystemId();
if (sid != null) {
sb.append(sid);
} else {
sb.append("the document");
}
sb.append('(');
sb.append(exception.getLineNumber());
sb.append(':');
sb.append(exception.getColumnNumber());
sb.append("): ");
sb.append(exception.getMessage());
return sb.toString();
}
public void fatalError(final SAXParseException exception) {
LOG.severe(messageFor(exception));
}
};
}