Java tutorial
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Anyone downloading information from this server is obligated to secure any necessary Government licenses before exporting documents or software obtained from this server. */ package org.dcache.alarms.jdom; import com.google.common.base.Preconditions; import com.google.common.base.Strings; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; import org.jdom.output.Format; import org.jdom.output.XMLOutputter; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.Writer; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.NoSuchElementException; import java.util.Properties; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import org.dcache.alarms.AlarmDefinition; import org.dcache.alarms.AlarmDefinitionsMap; /** * This implementation maintains current settings via the JDOM * implementation of the alarm definition, and writes and reads these from a * simple XML file. Definitions can be changed either directly in that file * (and then by reloading), or through the add command. * * @author arossi */ public final class XmlBackedAlarmDefinitionsMap implements AlarmDefinitionsMap<JDomAlarmDefinition> { private final Map<String, JDomAlarmDefinition> internalMap = new ConcurrentHashMap<>(); private String xmlDefinitionsPath; public void add(JDomAlarmDefinition definition) { internalMap.put(definition.getType(), definition); } public JDomAlarmDefinition getDefinition(String alarmType) throws NoSuchElementException { JDomAlarmDefinition definition = internalMap.get(alarmType); if (definition == null) { throw new NoSuchElementException(alarmType + " is not defined."); } return definition; } public Collection<JDomAlarmDefinition> getDefinitions() { return new ArrayList(internalMap.values()); } public void getSortedList(Writer writer) throws Exception { XMLOutputter outputter = new XMLOutputter(); outputter.setFormat(Format.getPrettyFormat()); outputter.output(getDocument(), writer); } public Set<String> getTypes() { return new HashSet(internalMap.keySet()); } public void initialize() throws JDOMException, IOException { load(new Properties()); } public void load(Properties env) throws JDOMException, IOException { internalMap.clear(); File xmlDefinitions = new File(env.getProperty(AlarmDefinitionsMap.PATH, xmlDefinitionsPath)); if (!xmlDefinitions.exists()) { return; } SAXBuilder builder = new SAXBuilder(); Document document = builder.build(xmlDefinitions); Element rootNode = document.getRootElement(); List<Element> list = rootNode.getChildren(AlarmDefinition.ALARM_TAG); if (!list.isEmpty()) { for (Element node : list) { add(new JDomAlarmDefinition(node)); } } } public JDomAlarmDefinition removeDefinition(String alarmType) { return internalMap.remove(alarmType); } public void save(Properties env) throws Exception { File xmlDefinitions = new File(env.getProperty(AlarmDefinitionsMap.PATH, xmlDefinitionsPath)); if (xmlDefinitions.exists()) { xmlDefinitions.delete(); } XMLOutputter outputter = new XMLOutputter(); outputter.setFormat(Format.getPrettyFormat()); try (FileOutputStream stream = new FileOutputStream(xmlDefinitions, false)) { outputter.output(getDocument(), stream); } } public void setDefinitionsPath(String xmlDefinitionsPath) { Preconditions.checkNotNull(Strings.emptyToNull(xmlDefinitionsPath)); this.xmlDefinitionsPath = xmlDefinitionsPath; } private Document getDocument() throws JDOMException { Document document = new Document(); Element root = new Element(JDomAlarmDefinition.ROOT_NAME); document.setRootElement(root); String[] keys = internalMap.keySet().toArray(new String[internalMap.size()]); Arrays.sort(keys); for (String key : keys) { root.addContent(internalMap.get(key).toElement()); } return document; } }