Java tutorial
/******************************************************************************* * Copyright (c) 2008 IBM Corporation 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: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.cdt.internal.ui.wizards.settingswizards; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.eclipse.core.resources.IProject; import org.eclipse.core.runtime.CoreException; import org.eclipse.jface.dialogs.IMessageProvider; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.xml.sax.ErrorHandler; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import org.eclipse.cdt.core.model.CoreModel; import org.eclipse.cdt.core.settings.model.ICConfigurationDescription; import org.eclipse.cdt.core.settings.model.ICFolderDescription; import org.eclipse.cdt.core.settings.model.ICProjectDescription; import org.eclipse.cdt.ui.CUIPlugin; /** * Custom behavior for the Import wizard. * * @author Mike Kucera * @since 5.1 * */ public class ProjectSettingsImportStrategy implements IProjectSettingsWizardPageStrategy { @Override public String getMessage(MessageType type) { switch (type) { case TITLE: return Messages.ProjectSettingsWizardPage_Import_title; case MESSAGE: return Messages.ProjectSettingsWizardPage_Import_message; case CHECKBOX: return Messages.ProjectSettingsWizardPage_Import_checkBox; case FILE: return Messages.ProjectSettingsWizardPage_Import_file; case SETTINGS: return Messages.ProjectSettingsWizardPage_Import_selectSettings; default: return null; } } /* * Start with an empty list of processors. */ @Override public void pageCreated(IProjectSettingsWizardPage page) { page.setDisplayedSettingsProcessors(Collections.<ISettingsProcessor>emptyList()); } /* * Collects the importers that can be applied to the file and displays * them to the user. */ @Override public void fileSelected(IProjectSettingsWizardPage page) { List<ImporterSectionPair> pairs = Collections.emptyList(); try { pairs = extractSectionsFromFile(page); page.setMessage(getMessage(MessageType.MESSAGE), IMessageProvider.NONE); // its all good } catch (FileNotFoundException e) { page.setMessage(Messages.ProjectSettingsWizardPage_Import_openError, IMessageProvider.ERROR); } catch (SettingsImportExportException e) { page.setMessage(Messages.ProjectSettingsWizardPage_Import_parseError, IMessageProvider.ERROR); } List<ISettingsProcessor> importersToDisplay = new ArrayList<ISettingsProcessor>(); for (ImporterSectionPair pair : pairs) { importersToDisplay.add(pair.importer); } // if there was an error then importersToDisplay will be empty and this will clear the list page.setDisplayedSettingsProcessors(importersToDisplay); } /* * Parse the file again and this time actually do the import. */ @Override public boolean finish(IProjectSettingsWizardPage page) { // get the selected project and configuration ICConfigurationDescription config = page.getSelectedConfiguration(); IProject project = config.getProjectDescription().getProject(); // get a writable copy of the project description so that we can make changes to it ICProjectDescription writableDescription = CoreModel.getDefault().getProjectDescription(project, true); ICConfigurationDescription writableConfig = writableDescription.getConfigurationById(config.getId()); ICFolderDescription writableProjectRoot = writableConfig.getRootFolderDescription(); List<ISettingsProcessor> selectedImporters = page.getSelectedSettingsProcessors(); try { List<ImporterSectionPair> pairs = extractSectionsFromFile(page); for (ImporterSectionPair pair : pairs) { if (selectedImporters.contains(pair.importer)) pair.importer.readSectionXML(writableProjectRoot, pair.section); } } catch (FileNotFoundException e) { CUIPlugin.log(e); page.showErrorDialog(Messages.ProjectSettingsImportStrategy_fileOpenError, Messages.ProjectSettingsImportStrategy_couldNotOpen); return false; } catch (SettingsImportExportException e) { // error during parsing or importing CUIPlugin.log(e); page.showErrorDialog(Messages.ProjectSettingsImportStrategy_importError, Messages.ProjectSettingsImportStrategy_couldNotImport); return false; } // only if all the importing was successful do we actually write out to the .cproject file try { CoreModel.getDefault().setProjectDescription(project, writableDescription); } catch (CoreException e) { CUIPlugin.log(e); page.showErrorDialog(Messages.ProjectSettingsImportStrategy_importError, Messages.ProjectSettingsImportStrategy_saveError); return false; } return true; } private static class ImporterSectionPair { Element section; ISettingsProcessor importer; ImporterSectionPair(ISettingsProcessor importer, Element section) { this.importer = importer; this.section = section; } } /* * Attempts to parse the file the user selected. */ private List<ImporterSectionPair> extractSectionsFromFile(IProjectSettingsWizardPage page) throws FileNotFoundException, SettingsImportExportException { // get the file path that the user input String filePath = page.getDestinationFilePath(); // get all the importers Map<String, ISettingsProcessor> importers = new HashMap<String, ISettingsProcessor>(); for (ISettingsProcessor processor : page.getSettingsProcessors()) { importers.put(processor.getSectionName(), processor); } FileInputStream in = new FileInputStream(filePath); // throws FileNotFoundException // try to parse the file as generic XML with no schema Document document = parse(in); // now try to get a list of <section> elements Element root = document.getDocumentElement(); List<Element> sections = XMLUtils.extractChildElements(root, ProjectSettingsExportStrategy.SECTION_ELEMENT); List<ImporterSectionPair> pairs = new ArrayList<ImporterSectionPair>(); // associate an importer with each section for (Element section : sections) { String sectionName = section.getAttribute(ProjectSettingsExportStrategy.SECTION_NAME_ATTRIBUTE); if (sectionName != null) { ISettingsProcessor importer = importers.get(sectionName); // if there is an importer available for the section then delegate to it if (importer != null) pairs.add(new ImporterSectionPair(importer, section)); } } return pairs; } /** * An error handler that aborts the XML parse at the first sign * of any kind of problem. */ private static ErrorHandler ABORTING_ERROR_HANDER = new ErrorHandler() { @Override public void error(SAXParseException e) throws SAXException { throw e; } @Override public void fatalError(SAXParseException e) throws SAXException { throw e; } @Override public void warning(SAXParseException e) throws SAXException { throw e; } }; /* * Uses JAXP to parse the file. Returns null if the file could * not be parsed as XML. * * Not validating because I want to make it easy to add new settings processors. * Eventually there could be an extension point for adding settings processors * so I'm coding everything with the assumption that each settings processor * will do its own validation programatically. */ private static Document parse(InputStream in) throws SettingsImportExportException { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); factory.setValidating(false); factory.setNamespaceAware(false); factory.setIgnoringComments(true); try { DocumentBuilder parser = factory.newDocumentBuilder(); parser.setErrorHandler(ABORTING_ERROR_HANDER); // causes SAXException to be thrown on any parse error InputSource input = new InputSource(in); // TODO should I be using an InputSource? Document doc = parser.parse(input); return doc; } catch (Exception e) { throw new SettingsImportExportException(e); } } }