/*******************************************************************************
* Copyright (c) 2007, 2008 Symbian Software Limited and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Bala Torati (Symbian) - Initial API and implementation
*******************************************************************************/
package org.eclipse.cdt.core.templateengine;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Result;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
/**
* Processes the shared default values. Updates and Persists new key - value (default) pair
*/
public class SharedDefaults extends HashMap<String, String> {
private static final long serialVersionUID = 0000000000L;
public Document document;
private File parsedXML;
private File backUpSharedXML;
/**
* HashMap's for persistence
*/
private HashMap<String, String> sharedDefaultsMap;
private HashMap<String, String> persistDataMap;
private HashMap<String, String> tableDataMap;
/**
* Two XML files here supports to provide consistent writing of data into
* them even during some destructive events which can happen during data
* persistence
*/
private static final String SHARED_DEFAULTS_DOT_XML = "shareddefaults.xml"; //$NON-NLS-1$
private static final String SHARED_DEFAULTS_DOT_BACKUP_DOT_XML = "shareddefaults.backup.xml"; //$NON-NLS-1$
/**
* Static reference string for getting (GET) and storing (SET)
* shareddefaults.xml
*/
public static final String SET = "SET"; //$NON-NLS-1$
public static final String GET = "GET"; //$NON-NLS-1$
/**
* Specifies the folder name present in the plugin
*/
public static final String ResourceFolder = "resources"; //$NON-NLS-1$
/**
* Static reference of Singleton SharedDefault Instance
*/
private static SharedDefaults SHAREDDEFAULTS = new SharedDefaults();
/**
* @return the shared SharedDefaults Instance
*/
public static SharedDefaults getInstance() {
return SHAREDDEFAULTS;
}
/**
* Default Constructor for creating and instantiating objects. On the
* startup of Template Engine, if it checks for the existence of
* TempSharedDefaultsXML file, then it is determined that the last Template
* Engine process under went some System destructive events and takes up
* reconstructive process to regain the consistent data by persisting all
* information first into temporary file and then into actual file.
*/
public SharedDefaults() {
sharedDefaultsMap = new HashMap<String, String>();
persistDataMap = new HashMap<String, String>();
tableDataMap = new HashMap<String, String>();
// The conditional controls here is provided to have consistent
// data storage in the file during System crash or
// Power shutdown during data persistence into the file.
parsedXML = TemplateEngineHelper.getSharedDefaultLocation(SHARED_DEFAULTS_DOT_XML);
backUpSharedXML = TemplateEngineHelper.getSharedDefaultLocation(SHARED_DEFAULTS_DOT_BACKUP_DOT_XML);
if (backUpSharedXML.exists())
swapXML();
initSharedDefaults();
}
/**
* This method instantiates the SharedDefaults process by gathering XML
* document and creating shared key-value pair in HashMap. Also creates a
* new XML file if none exists and adds the default XML format.
*/
private void initSharedDefaults() {
String key = null;
String value = null;
try {
long length = parsedXML.length();
// Adds defaultXML format if the file length is zero
if (length == 0) {
parsedXML = createDefaultXMLFormat(parsedXML);
}
document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(parsedXML.toURI().toURL().openStream());
} catch (Exception exp) {
TemplateEngineUtil.log(exp);
}
List<Element> sharedElementList = TemplateEngine.getChildrenOfElement(document.getDocumentElement());
int listSize = sharedElementList.size();
for (int i = 0; i < listSize; i++) {
Element xmlElement = sharedElementList.get(i);
key = xmlElement.getAttribute(TemplateEngineHelper.ID);
value = xmlElement.getAttribute(TemplateEngineHelper.VALUE);
if (key != null && !key.trim().equals("")) { //$NON-NLS-1$
sharedDefaultsMap.put(key, value);
}
}
}
/**
* This method updates the HashMap with new key-value pair into the XML file
*
* @param sharedMap
*/
public void updateShareDefaultsMap(Map<String, String> sharedMap) {
sharedDefaultsMap.putAll(sharedMap);
persistSharedValueMap();
}
/**
* This method persists the latest data (HashMap) in the XML file New data
* obtained from the PreferencePage GUI.
*/
public void persistSharedValueMap() {
generateSharedXML(backUpSharedXML);
generateSharedXML(parsedXML);
swapXML();
}
/**
* This method returns the latest key value pair (HashMap)
*
* @return HashMap
*/
public Map<String, String> getSharedDefaultsMap() {
return sharedDefaultsMap;
}
/**
* Adds data to the backend XML (persistence) Data obtained from the
* PreferencePage GUI.
*/
public void addToBackEndStorage(String name, String value) {
if (sharedDefaultsMap != null) {
tableDataMap.putAll(sharedDefaultsMap);
}
tableDataMap.put(name, value);
updateShareDefaultsMap(tableDataMap);
}
/**
* Updates backend with changed value for a specific key(name)
*
* @param updateName
* @param updateValue
*/
public void updateToBackEndStorage(String updateName, String updateValue) {
try {
document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(parsedXML.toURI().toURL().openStream());
} catch (Exception exp) {
TemplateEngineUtil.log(exp);
}
persistDataMap.putAll(sharedDefaultsMap);
List<Element> sharedElementList = TemplateEngine.getChildrenOfElement(document.getDocumentElement());
int elementListSize = sharedElementList.size();
for (int i = 0; i < elementListSize; i++) {
Element xmlElement = sharedElementList.get(i);
String name = xmlElement.getAttribute(TemplateEngineHelper.ID);
if (updateName.equals(name)) {
persistDataMap.put(updateName, updateValue);
}
}
updateShareDefaultsMap(persistDataMap);
}
/**
* Deletes the key-value pair from the backend with Key as identifier.
*
* @param deleteName
*/
public void deleteBackEndStorage(String[] deleteName) {
try {
document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(parsedXML.toURI().toURL().openStream());
} catch (Exception exp) {
TemplateEngineUtil.log(exp);
}
List<Element> sharedElementList = TemplateEngine.getChildrenOfElement(document.getDocumentElement());
int elementListSize = sharedElementList.size();
for (int i = 0; i < elementListSize; i++) {
Element xmlElement = sharedElementList.get(i);
String name = xmlElement.getAttribute(TemplateEngineHelper.ID);
for (int k = 0; k < deleteName.length; k++) {
if (deleteName[k].equals(name)) {
xmlElement.removeAttribute(name);
sharedDefaultsMap.remove(name);
}
}
}
updateShareDefaultsMap(sharedDefaultsMap);
}
/**
* This method returns the default XMLFormat for the newly created XML file
*
* @param parsedXML
* @return
*/
private File createDefaultXMLFormat(File xmlFile) {
Document d;
try {
d = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
} catch (ParserConfigurationException e) {
TemplateEngineUtil.log(e);
return xmlFile;
}
Node rootElement = d.appendChild(d.createElement("SharedRoot")); //$NON-NLS-1$
Element element = (Element) rootElement.appendChild(d.createElement("SharedProperty")); //$NON-NLS-1$
element.setAttribute(TemplateEngineHelper.ID, ""); //$NON-NLS-1$
element.setAttribute(TemplateEngineHelper.VALUE, ""); //$NON-NLS-1$
DOMSource domSource = new DOMSource(d);
TransformerFactory transFactory = TransformerFactory.newInstance();
try {
FileOutputStream fos= null;
try {
fos= new FileOutputStream(xmlFile);
Result fileResult = new StreamResult(fos);
transFactory.newTransformer().transform(domSource, fileResult);
} finally {
if(fos!=null) {
fos.close();
}
}
} catch(IOException ioe) {
TemplateEngineUtil.log(ioe);
} catch(TransformerConfigurationException tce) {
TemplateEngineUtil.log(tce);
} catch(TransformerException te) {
TemplateEngineUtil.log(te);
}
return xmlFile;
}
/**
* This method generates XML file for backupshareddefaults and
* shareddefaults to support consistent persistency
*/
private void generateSharedXML(File xmlFile) {
Document d;
try {
d = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
} catch (ParserConfigurationException e) {
TemplateEngineUtil.log(e);
return;
}
Node rootElement = d.appendChild(d.createElement("SharedRoot")); //$NON-NLS-1$
for(String key : sharedDefaultsMap.keySet()) {
Element element = (Element) rootElement.appendChild(d.createElement("SharedProperty")); //$NON-NLS-1$
element.setAttribute(TemplateEngineHelper.ID, key);
element.setAttribute(TemplateEngineHelper.VALUE, sharedDefaultsMap.get(key));
}
DOMSource domSource = new DOMSource(d);
TransformerFactory transFactory = TransformerFactory.newInstance();
Result fileResult = new StreamResult(xmlFile);
try {
transFactory.newTransformer().transform(domSource, fileResult);
} catch (Throwable t) {
TemplateEngineUtil.log(t);
}
}
/**
* This method swaps the backup file name to XML file containing latest or
* persisted data
*/
private void swapXML() {
if (parsedXML.exists())
parsedXML.delete();
backUpSharedXML.renameTo(parsedXML);
}
}