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/*
 *  streams library
 *
 *  Copyright (C) 2011-2014 by Christian Bockermann, Hendrik Blom
 * 
 *  streams is a library, API and runtime environment for processing high
 *  volume data streams. It is composed of three submodules "stream-api",
 *  "stream-core" and "stream-runtime".
 *
 *  The streams library (and its submodules) is free software: you can 
 *  redistribute it and/or modify it under the terms of the 
 *  GNU Affero General Public License as published by the Free Software 
 *  Foundation, either version 3 of the License, or (at your option) any 
 *  later version.
 *
 *  The stream.ai library (and its submodules) is distributed in the hope
 *  that it will be useful, but WITHOUT ANY WARRANTY; without even the implied 
 *  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package stream.util;

import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import stream.io.SourceURL;

public class PropertiesHandler {

	private Logger log = LoggerFactory.getLogger(PropertiesHandler.class);

	/**
	 * This method adds properties defined in the format as provided by maven's
	 * <properties>...</properties> element.
	 * 
	 * @param pop
	 *            The XML element that is to be checked for properties
	 * @param variables
	 *            The variables that have been gathered so far
	 * @param systemProperties
	 *            Variables provided through system properties
	 */
	public void handlePropertiesElement(Element prop, Variables variables,
			Variables systemProperties) {

		String suffix = "";
		if (prop.hasAttribute("suffix")) {
			suffix = prop.getAttribute("suffix");
			log.info("Add suffix {} to properties.", suffix);
		}

		NodeList children = prop.getChildNodes();
		if (children.getLength() > 0) {
			// TextNodes
			for (int k = 0; k < children.getLength(); k++) {

				Node ch = children.item(k);
				if (ch.getNodeType() == Node.ELEMENT_NODE) {

					String key = ch.getNodeName();
					String value = ch.getTextContent();

					variables.set(key + suffix, value);
				}
			}

		}
		// Properties from URL
		else if (prop.hasAttribute("url")) {
			String purl = prop.getAttribute("url");
			log.debug("Reading properties from URL {}", purl);
			try {
				// ORDER IMPORTANT
				Variables props = new Variables(variables);
				props.addVariables(systemProperties);
				purl = props.expand(purl);
				log.debug("Properties URL is: {}", purl);

				SourceURL propUrl = new SourceURL(purl);

				Properties p = new Properties();
				p.load(propUrl.openStream());
				for (Object k : p.keySet()) {
					String key = k.toString();
					String value = p.getProperty(key);
					value = variables.expand(value, false);
					log.debug("Adding property '{}' = '{}'", key, value);
					variables.set(key + suffix, value);
				}

			} catch (Exception e) {
				log.error("Failed to read properties from url {}: {}", purl,
						e.getMessage());
			}
			// Properties from URL
		} else if (prop.hasAttribute("file")) {
			File file = new File(prop.getAttribute("file"));
			try {
				Properties p = new Properties();
				p.load(new FileInputStream(file));
				for (Object k : p.keySet()) {
					variables.set(k.toString() + suffix,
							p.getProperty(k.toString()));
				}
			} catch (Exception e) {
				log.error("Failed to read properties from file {}: {}", file,
						e.getMessage());
			}
		}

	}

	public void handlePropertyElement(Element prop, Variables variables,
			Variables systemVariables) {
		if (prop.getNodeName().equalsIgnoreCase("property")) {

			String key = prop.getAttribute("name");
			String value = prop.getAttribute("value");

			if (key != null && !"".equals(key.trim()) && value != null
					&& !"".equals(value.trim())) {
				// ORDER IMPORTANT
				Variables props = new Variables(variables);
				props.addVariables(systemVariables);
				String k = key.trim();
				String v = value.trim();
				// ORDER IMPORTANT
				// // All found variables ()
				v = props.expand(v);
				// log.info("Setting property {} = {}", k, v);
				variables.set(k, v);
			}
		}
	}

	/**
	 * This method adds all the system properties to the container properties,
	 * possibly overwriting pre-defined properties.
	 * 
	 * @param variables
	 *            The collection of variables to add the system properties to.
	 */
	public void addSystemProperties(Variables variables) {
		for (Object key : System.getProperties().keySet()) {
			variables.set(key.toString(), System.getProperty(key.toString()));
		}
	}

}