Always set the current hash when inserting.
[jSite.git] / src / de / todesbaum / jsite / application / ProjectInserter.java
index 1b0021a..158a0bb 100644 (file)
@@ -1,6 +1,5 @@
 /*
- * jSite - a tool for uploading websites into Freenet
- * Copyright (C) 2006 David Roden
+ * jSite - ProjectInserter.java - Copyright © 2006–2011 David Roden
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
 
 package de.todesbaum.jsite.application;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipOutputStream;
+import java.util.Set;
+import java.util.Map.Entry;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import de.todesbaum.jsite.gui.FileScanner;
+import de.todesbaum.jsite.gui.FileScanner.ScannedFile;
 import de.todesbaum.jsite.gui.FileScannerListener;
 import de.todesbaum.util.freenet.fcp2.Client;
 import de.todesbaum.util.freenet.fcp2.ClientPutComplexDir;
+import de.todesbaum.util.freenet.fcp2.ClientPutDir.ManifestPutter;
 import de.todesbaum.util.freenet.fcp2.Connection;
 import de.todesbaum.util.freenet.fcp2.DirectFileEntry;
 import de.todesbaum.util.freenet.fcp2.FileEntry;
 import de.todesbaum.util.freenet.fcp2.Message;
 import de.todesbaum.util.freenet.fcp2.RedirectFileEntry;
 import de.todesbaum.util.freenet.fcp2.Verbosity;
-import de.todesbaum.util.io.Closer;
-import de.todesbaum.util.io.ReplacingOutputStream;
-import de.todesbaum.util.io.StreamCopier;
+import de.todesbaum.util.io.StreamCopier.ProgressListener;
 
 /**
- * @author David Roden <droden@gmail.com>
- * @version $Id$
+ * Manages project inserts.
+ *
+ * @author David ‘Bombe’ Roden <bombe@freenetproject.org>
  */
 public class ProjectInserter implements FileScannerListener, Runnable {
 
+       /** The logger. */
+       private static final Logger logger = Logger.getLogger(ProjectInserter.class.getName());
+
+       /** Random number for FCP instances. */
+       private static final int random = (int) (Math.random() * Integer.MAX_VALUE);
+
+       /** Counter for FCP connection identifier. */
        private static int counter = 0;
-       private boolean debug = false;
+
+       /** The list of insert listeners. */
        private List<InsertListener> insertListeners = new ArrayList<InsertListener>();
+
+       /** The freenet interface. */
        protected Freenet7Interface freenetInterface;
+
+       /** The project to insert. */
        protected Project project;
+
+       /** The file scanner. */
        private FileScanner fileScanner;
+
+       /** Object used for synchronization. */
        protected final Object lockObject = new Object();
 
+       /** The temp directory. */
+       private String tempDirectory;
+
+       /** The current connection. */
+       private Connection connection;
+
+       /** Whether the insert is cancelled. */
+       private volatile boolean cancelled = false;
+
+       /** Progress listener for payload transfers. */
+       private ProgressListener progressListener;
+
+       /**
+        * Adds a listener to the list of registered listeners.
+        *
+        * @param insertListener
+        *            The listener to add
+        */
        public void addInsertListener(InsertListener insertListener) {
                insertListeners.add(insertListener);
        }
 
+       /**
+        * Removes a listener from the list of registered listeners.
+        *
+        * @param insertListener
+        *            The listener to remove
+        */
        public void removeInsertListener(InsertListener insertListener) {
                insertListeners.remove(insertListener);
        }
 
+       /**
+        * Notifies all listeners that the project insert has started.
+        *
+        * @see InsertListener#projectInsertStarted(Project)
+        */
        protected void fireProjectInsertStarted() {
-               for (InsertListener insertListener: insertListeners) {
+               for (InsertListener insertListener : insertListeners) {
                        insertListener.projectInsertStarted(project);
                }
        }
-       
+
+       /**
+        * Notifies all listeners that the insert has generated a URI.
+        *
+        * @see InsertListener#projectURIGenerated(Project, String)
+        * @param uri
+        *            The generated URI
+        */
        protected void fireProjectURIGenerated(String uri) {
-               for (InsertListener insertListener: insertListeners) {
+               for (InsertListener insertListener : insertListeners) {
                        insertListener.projectURIGenerated(project, uri);
                }
        }
 
-       protected void fireProjectInsertProgress(int succeeded, int failed, int fatal, int total, boolean finalized) {
-               for (InsertListener insertListener: insertListeners) {
-                       insertListener.projectInsertProgress(project, succeeded, failed, fatal, total, finalized);
+       /**
+        * Notifies all listeners that the insert has made some progress.
+        *
+        * @see InsertListener#projectUploadFinished(Project)
+        */
+       protected void fireProjectUploadFinished() {
+               for (InsertListener insertListener : insertListeners) {
+                       insertListener.projectUploadFinished(project);
                }
        }
 
-       protected void fireProjectInsertFinished(boolean success, Throwable cause) {
-               for (InsertListener insertListener: insertListeners) {
-                       insertListener.projectInsertFinished(project, success, cause);
+       /**
+        * Notifies all listeners that the insert has made some progress.
+        *
+        * @see InsertListener#projectInsertProgress(Project, int, int, int, int,
+        *      boolean)
+        * @param succeeded
+        *            The number of succeeded blocks
+        * @param failed
+        *            The number of failed blocks
+        * @param fatal
+        *            The number of fatally failed blocks
+        * @param total
+        *            The total number of blocks
+        * @param finalized
+        *            <code>true</code> if the total number of blocks has already
+        *            been finalized, <code>false</code> otherwise
+        */
+       protected void fireProjectInsertProgress(int succeeded, int failed, int fatal, int total, boolean finalized) {
+               for (InsertListener insertListener : insertListeners) {
+                       insertListener.projectInsertProgress(project, succeeded, failed, fatal, total, finalized);
                }
        }
 
        /**
-        * @param debug
-        *            The debug to set.
+        * Notifies all listeners the project insert has finished.
+        *
+        * @see InsertListener#projectInsertFinished(Project, boolean, Throwable)
+        * @param success
+        *            <code>true</code> if the project was inserted successfully,
+        *            <code>false</code> if it failed
+        * @param cause
+        *            The cause of the failure, if any
         */
-       public void setDebug(boolean debug) {
-               this.debug = debug;
+       protected void fireProjectInsertFinished(boolean success, Throwable cause) {
+               for (InsertListener insertListener : insertListeners) {
+                       insertListener.projectInsertFinished(project, success, cause);
+               }
        }
 
        /**
+        * Sets the project to insert.
+        *
         * @param project
-        *            The project to set.
+        *            The project to insert
         */
        public void setProject(Project project) {
                this.project = project;
        }
 
        /**
+        * Sets the freenet interface to use.
+        *
         * @param freenetInterface
-        *            The freenetInterface to set.
+        *            The freenet interface to use
         */
        public void setFreenetInterface(Freenet7Interface freenetInterface) {
                this.freenetInterface = freenetInterface;
        }
 
-       public void start() {
+       /**
+        * Sets the temp directory to use.
+        *
+        * @param tempDirectory
+        *            The temp directory to use, or {@code null} to use the system
+        *            default
+        */
+       public void setTempDirectory(String tempDirectory) {
+               this.tempDirectory = tempDirectory;
+       }
+
+       /**
+        * Starts the insert.
+        *
+        * @param progressListener
+        *            Listener to notify on progress events
+        */
+       public void start(ProgressListener progressListener) {
+               cancelled = false;
+               this.progressListener = progressListener;
                fileScanner = new FileScanner(project);
                fileScanner.addFileScannerListener(this);
                new Thread(fileScanner).start();
        }
 
-       private InputStream createFileInputStream(String filename, FileOption fileOption, int edition, long[] length) throws IOException {
-               File file = new File(project.getLocalPath(), filename);
-               length[0] = file.length();
-               if (!fileOption.getReplaceEdition()) {
-                       return new FileInputStream(file);
-               }
-               ByteArrayOutputStream filteredByteOutputStream = new ByteArrayOutputStream(Math.min(Integer.MAX_VALUE, (int) length[0]));
-               ReplacingOutputStream outputStream = new ReplacingOutputStream(filteredByteOutputStream);
-               FileInputStream fileInput = new FileInputStream(file);
-               try {
-                       outputStream.addReplacement("$[EDITION]", String.valueOf(edition));
-                       outputStream.addReplacement("$[URI]", project.getFinalRequestURI(0));
-                       for (int index = 1; index <= fileOption.getEditionRange(); index++) {
-                               outputStream.addReplacement("$[URI+" + index + "]", project.getFinalRequestURI(index));
-                               outputStream.addReplacement("$[EDITION+" + index + "]", String.valueOf(edition + index));
-                       }
-                       StreamCopier.copy(fileInput, outputStream, length[0]);
-               } finally {
-                       Closer.close(fileInput);
-                       Closer.close(outputStream);
-                       Closer.close(filteredByteOutputStream);
-               }
-               byte[] filteredBytes = filteredByteOutputStream.toByteArray();
-               length[0] = filteredBytes.length;
-               return new ByteArrayInputStream(filteredBytes);
-       }
-
-       private InputStream createContainerInputStream(Map<String, List<String>> containerFiles, String containerName, int edition, long[] containerLength) throws IOException {
-               File tempFile = File.createTempFile("jsite", ".zip");
-               tempFile.deleteOnExit();
-               FileOutputStream fileOutputStream = new FileOutputStream(tempFile);
-               ZipOutputStream zipOutputStream = new ZipOutputStream(fileOutputStream);
-               try {
-                       for (String filename: containerFiles.get(containerName)) {
-                               File dataFile = new File(project.getLocalPath(), filename);
-                               if (dataFile.exists()) {
-                                       ZipEntry zipEntry = new ZipEntry(filename);
-                                       long[] fileLength = new long[1];
-                                       InputStream wrappedInputStream = createFileInputStream(filename, project.getFileOption(filename), edition, fileLength);
-                                       try {
-                                               zipOutputStream.putNextEntry(zipEntry);
-                                               StreamCopier.copy(wrappedInputStream, zipOutputStream, fileLength[0]);
-                                       } finally {
-                                               zipOutputStream.closeEntry();
-                                               wrappedInputStream.close();
-                                       }
-                               }
+       /**
+        * Stops the current insert.
+        */
+       public void stop() {
+               cancelled = true;
+               synchronized (lockObject) {
+                       if (connection != null) {
+                               connection.disconnect();
                        }
-               } finally {     
-                       zipOutputStream.closeEntry();
-                       Closer.close(zipOutputStream);
-                       Closer.close(fileOutputStream);
                }
+       }
 
-               containerLength[0] = tempFile.length();
-               return new FileInputStream(tempFile);
+       /**
+        * Creates an input stream that delivers the given file, replacing edition
+        * tokens in the file’s content, if necessary.
+        *
+        * @param filename
+        *            The name of the file
+        * @param fileOption
+        *            The file options
+        * @param edition
+        *            The current edition
+        * @param length
+        *            An array containing a single long which is used to
+        *            <em>return</em> the final length of the file, after all
+        *            replacements
+        * @return The input stream for the file
+        * @throws IOException
+        *             if an I/O error occurs
+        */
+       private InputStream createFileInputStream(String filename, FileOption fileOption, int edition, long[] length) throws IOException {
+               File file = new File(project.getLocalPath(), filename);
+               length[0] = file.length();
+               return new FileInputStream(file);
        }
 
-       private FileEntry createFileEntry(String filename, int edition, Map<String, List<String>> containerFiles) {
+       /**
+        * Creates a file entry suitable for handing in to
+        * {@link ClientPutComplexDir#addFileEntry(FileEntry)}.
+        *
+        * @param file
+        *            The name and hash of the file to insert
+        * @param edition
+        *            The current edition
+        * @return A file entry for the given file
+        */
+       private FileEntry createFileEntry(ScannedFile file, int edition) {
                FileEntry fileEntry = null;
+               String filename = file.getFilename();
                FileOption fileOption = project.getFileOption(filename);
-               if (filename.startsWith("/container/:")) {
-                       String containerName = filename.substring("/container/:".length());
+               if (fileOption.isInsert()) {
+                       fileOption.setCurrentHash(file.getHash());
+                       /* check if file was modified. */
+                       if (file.getHash().equals(fileOption.getLastInsertHash())) {
+                               /* only insert a redirect. */
+                               logger.log(Level.FINE, String.format("Inserting redirect to edition %d for %s.", fileOption.getLastInsertEdition(), filename));
+                               return new RedirectFileEntry(filename, fileOption.getMimeType(), "SSK@" + project.getRequestURI() + "/" + project.getPath() + "-" + fileOption.getLastInsertEdition() + "/" + filename);
+                       }
                        try {
-                               long[] containerLength = new long[1];
-                               InputStream containerInputStream = createContainerInputStream(containerFiles, containerName, edition, containerLength);
-                               fileEntry = new DirectFileEntry(containerName + ".zip", "application/zip", containerInputStream, containerLength[0]);
+                               long[] fileLength = new long[1];
+                               InputStream fileEntryInputStream = createFileInputStream(filename, fileOption, edition, fileLength);
+                               fileEntry = new DirectFileEntry(filename, fileOption.getMimeType(), fileEntryInputStream, fileLength[0]);
                        } catch (IOException ioe1) {
+                               /* ignore, null is returned. */
                        }
                } else {
-                       if (fileOption.isInsert()) {
-                               try {
-                                       long[] fileLength = new long[1];
-                                       InputStream fileEntryInputStream = createFileInputStream(filename, fileOption, edition, fileLength);
-                                       fileEntry = new DirectFileEntry(filename, project.getFileOption(filename).getMimeType(), fileEntryInputStream, fileLength[0]);
-                               } catch (IOException ioe1) {
-                               }
-                       } else {
+                       if (fileOption.isInsertRedirect()) {
                                fileEntry = new RedirectFileEntry(filename, fileOption.getMimeType(), fileOption.getCustomKey());
+                       } else {
+                               fileOption.setLastInsertHash("");
                        }
                }
                return fileEntry;
        }
 
-       private void createContainers(List<String> files, List<String> containers, Map<String, List<String>> containerFiles) {
-               for (String filename: new ArrayList<String>(files)) {
-                       FileOption fileOption = project.getFileOption(filename);
-                       String containerName = fileOption.getContainer();
-                       if (!containerName.equals("")) {
-                               if (!containers.contains(containerName)) {
-                                       containers.add(containerName);
-                                       containerFiles.put(containerName, new ArrayList<String>());
-                                       /* hmm. looks like a hack to me. */
-                                       files.add("/container/:" + containerName);
-                               }
-                               containerFiles.get(containerName).add(filename);
-                               files.remove(filename);
+       /**
+        * Validates the given project. The project will be checked for any invalid
+        * conditions, such as invalid insert or request keys, missing path names,
+        * missing default file, and so on.
+        *
+        * @param project
+        *            The project to check
+        * @return The encountered warnings and errors
+        */
+       public static CheckReport validateProject(Project project) {
+               CheckReport checkReport = new CheckReport();
+               if ((project.getLocalPath() == null) || (project.getLocalPath().trim().length() == 0)) {
+                       checkReport.addIssue("error.no-local-path", true);
+               }
+               if ((project.getPath() == null) || (project.getPath().trim().length() == 0)) {
+                       checkReport.addIssue("error.no-path", true);
+               }
+               if ((project.getIndexFile() == null) || (project.getIndexFile().length() == 0)) {
+                       checkReport.addIssue("warning.empty-index", false);
+               } else {
+                       File indexFile = new File(project.getLocalPath(), project.getIndexFile());
+                       if (!indexFile.exists()) {
+                               checkReport.addIssue("error.index-missing", true);
+                       }
+               }
+               String indexFile = project.getIndexFile();
+               boolean hasIndexFile = (indexFile != null) && (indexFile.length() > 0);
+               List<String> allowedIndexContentTypes = Arrays.asList("text/html", "application/xhtml+xml");
+               if (hasIndexFile && !allowedIndexContentTypes.contains(project.getFileOption(indexFile).getMimeType())) {
+                       checkReport.addIssue("warning.index-not-html", false);
+               }
+               Map<String, FileOption> fileOptions = project.getFileOptions();
+               Set<Entry<String, FileOption>> fileOptionEntries = fileOptions.entrySet();
+               boolean insert = fileOptionEntries.isEmpty();
+               for (Entry<String, FileOption> fileOptionEntry : fileOptionEntries) {
+                       String fileName = fileOptionEntry.getKey();
+                       FileOption fileOption = fileOptionEntry.getValue();
+                       insert |= fileOption.isInsert() || fileOption.isInsertRedirect();
+                       if (fileName.equals(project.getIndexFile()) && !fileOption.isInsert() && !fileOption.isInsertRedirect()) {
+                               checkReport.addIssue("error.index-not-inserted", true);
                        }
+                       if (!fileOption.isInsert() && fileOption.isInsertRedirect() && ((fileOption.getCustomKey().length() == 0) || "CHK@".equals(fileOption.getCustomKey()))) {
+                               checkReport.addIssue("error.no-custom-key", true, fileName);
+                       }
+               }
+               if (!insert) {
+                       checkReport.addIssue("error.no-files-to-insert", true);
                }
+               Set<String> fileNames = new HashSet<String>();
+               for (Entry<String, FileOption> fileOptionEntry : fileOptionEntries) {
+                       FileOption fileOption = fileOptionEntry.getValue();
+                       if (!fileOption.isInsert() && !fileOption.isInsertRedirect()) {
+                               logger.log(Level.FINEST, "Ignoring {0}.", fileOptionEntry.getKey());
+                               continue;
+                       }
+                       String fileName = fileOptionEntry.getKey();
+                       if (fileOption.hasChangedName()) {
+                               fileName = fileOption.getChangedName();
+                       }
+                       logger.log(Level.FINEST, "Adding “{0}” for {1}.", new Object[] { fileName, fileOptionEntry.getKey() });
+                       if (!fileNames.add(fileName)) {
+                               checkReport.addIssue("error.duplicate-file", true, fileName);
+                       }
+               }
+               return checkReport;
        }
 
        /**
@@ -229,10 +376,13 @@ public class ProjectInserter implements FileScannerListener, Runnable {
         */
        public void run() {
                fireProjectInsertStarted();
-               List<String> files = fileScanner.getFiles();
+               List<ScannedFile> files = fileScanner.getFiles();
 
                /* create connection to node */
-               Connection connection = freenetInterface.getConnection("project-insert-" + counter++);
+               synchronized (lockObject) {
+                       connection = freenetInterface.getConnection("project-insert-" + random + counter++);
+               }
+               connection.setTempDirectory(tempDirectory);
                boolean connected = false;
                Throwable cause = null;
                try {
@@ -240,36 +390,41 @@ public class ProjectInserter implements FileScannerListener, Runnable {
                } catch (IOException e1) {
                        cause = e1;
                }
-               
-               if (!connected) {
-                       fireProjectInsertFinished(false, cause);
+
+               if (!connected || cancelled) {
+                       fireProjectInsertFinished(false, cancelled ? new AbortedException() : cause);
                        return;
                }
-               
-               Client client = new Client(connection);
 
-               /* create containers */
-               final List<String> containers = new ArrayList<String>();
-               final Map<String, List<String>> containerFiles = new HashMap<String, List<String>>();
-               createContainers(files, containers, containerFiles);
+               Client client = new Client(connection);
 
                /* collect files */
                int edition = project.getEdition();
-               String dirURI = "freenet:USK@" + project.getInsertURI() + "/" + project.getPath() + "/" + edition + "/";
-               ClientPutComplexDir putDir = new ClientPutComplexDir("dir-" + counter++, dirURI);
-               putDir.setDefaultName(project.getIndexFile());
+               String dirURI = "USK@" + project.getInsertURI() + "/" + project.getPath() + "/" + edition + "/";
+               ClientPutComplexDir putDir = new ClientPutComplexDir("dir-" + counter++, dirURI, tempDirectory);
+               if ((project.getIndexFile() != null) && (project.getIndexFile().length() > 0)) {
+                       putDir.setDefaultName(project.getIndexFile());
+               }
                putDir.setVerbosity(Verbosity.ALL);
                putDir.setMaxRetries(-1);
-               for (String filename: files) {
-                       FileEntry fileEntry = createFileEntry(filename, edition, containerFiles);
+               putDir.setEarlyEncode(false);
+               putDir.setManifestPutter(ManifestPutter.DEFAULT);
+               for (ScannedFile file : files) {
+                       FileEntry fileEntry = createFileEntry(file, edition);
                        if (fileEntry != null) {
-                               putDir.addFileEntry(fileEntry);
+                               try {
+                                       putDir.addFileEntry(fileEntry);
+                               } catch (IOException ioe1) {
+                                       fireProjectInsertFinished(false, ioe1);
+                                       return;
+                               }
                        }
                }
 
                /* start request */
                try {
-                       client.execute(putDir);
+                       client.execute(putDir, progressListener);
+                       fireProjectUploadFinished();
                } catch (IOException ioe1) {
                        fireProjectInsertFinished(false, ioe1);
                        return;
@@ -280,13 +435,12 @@ public class ProjectInserter implements FileScannerListener, Runnable {
                boolean success = false;
                boolean finished = false;
                boolean disconnected = false;
-               while (!finished) {
+               while (!finished && !cancelled) {
                        Message message = client.readMessage();
                        finished = (message == null) || (disconnected = client.isDisconnected());
-                       if (debug) {
-                               System.out.println(message);
-                       }
+                       logger.log(Level.FINE, "Received message: " + message);
                        if (!finished) {
+                               @SuppressWarnings("null")
                                String messageName = message.getName();
                                if ("URIGenerated".equals(messageName)) {
                                        finalURI = message.get("URI");
@@ -300,18 +454,21 @@ public class ProjectInserter implements FileScannerListener, Runnable {
                                        boolean finalized = Boolean.parseBoolean(message.get("FinalizedTotal"));
                                        fireProjectInsertProgress(succeeded, failed, fatal, total, finalized);
                                }
-                               success = "PutSuccessful".equals(messageName);
-                               finished = success || "PutFailed".equals(messageName);
+                               success |= "PutSuccessful".equals(messageName);
+                               finished = (success && (finalURI != null)) || "PutFailed".equals(messageName) || messageName.endsWith("Error");
                        }
                }
 
                /* post-insert work */
-               fireProjectInsertFinished(success, disconnected ? new IOException("Connection terminated") : null);
                if (success) {
+                       @SuppressWarnings("null")
                        String editionPart = finalURI.substring(finalURI.lastIndexOf('/') + 1);
                        int newEdition = Integer.parseInt(editionPart);
                        project.setEdition(newEdition);
+                       project.setLastInsertionTime(System.currentTimeMillis());
+                       project.copyHashes();
                }
+               fireProjectInsertFinished(success, cancelled ? new AbortedException() : (disconnected ? new IOException("Connection terminated") : null));
        }
 
        //
@@ -330,4 +487,138 @@ public class ProjectInserter implements FileScannerListener, Runnable {
                fileScanner.removeFileScannerListener(this);
        }
 
+       /**
+        * Container class that collects all warnings and errors that occured during
+        * {@link ProjectInserter#validateProject(Project) project validation}.
+        *
+        * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+        */
+       public static class CheckReport implements Iterable<Issue> {
+
+               /** The issures that occured. */
+               private final List<Issue> issues = new ArrayList<Issue>();
+
+               /**
+                * Adds an issue.
+                *
+                * @param issue
+                *            The issue to add
+                */
+               public void addIssue(Issue issue) {
+                       issues.add(issue);
+               }
+
+               /**
+                * Creates an {@link Issue} from the given error key and fatality flag
+                * and {@link #addIssue(Issue) adds} it.
+                *
+                * @param errorKey
+                *            The error key
+                * @param fatal
+                *            {@code true} if the error is fatal, {@code false} if only
+                *            a warning should be generated
+                * @param parameters
+                *            Any additional parameters
+                */
+               public void addIssue(String errorKey, boolean fatal, String... parameters) {
+                       addIssue(new Issue(errorKey, fatal, parameters));
+               }
+
+               /**
+                * {@inheritDoc}
+                */
+               public Iterator<Issue> iterator() {
+                       return issues.iterator();
+               }
+
+               /**
+                * Returns whether this check report does not contain any errors.
+                *
+                * @return {@code true} if this check report does not contain any
+                *         errors, {@code false} if this check report does contain
+                *         errors
+                */
+               public boolean isEmpty() {
+                       return issues.isEmpty();
+               }
+
+               /**
+                * Returns the number of issues in this check report.
+                *
+                * @return The number of issues
+                */
+               public int size() {
+                       return issues.size();
+               }
+
+       }
+
+       /**
+        * Container class for a single issue. An issue contains an error key
+        * that describes the error, and a fatality flag that determines whether
+        * the insert has to be aborted (if the flag is {@code true}) or if it
+        * can still be performed and only a warning should be generated (if the
+        * flag is {@code false}).
+        *
+        * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’
+        *         Roden</a>
+        */
+       public static class Issue {
+
+               /** The error key. */
+               private final String errorKey;
+
+               /** The fatality flag. */
+               private final boolean fatal;
+
+               /** Additional parameters. */
+               private String[] parameters;
+
+               /**
+                * Creates a new issue.
+                *
+                * @param errorKey
+                *            The error key
+                * @param fatal
+                *            The fatality flag
+                * @param parameters
+                *            Any additional parameters
+                */
+               protected Issue(String errorKey, boolean fatal, String... parameters) {
+                       this.errorKey = errorKey;
+                       this.fatal = fatal;
+                       this.parameters = parameters;
+               }
+
+               /**
+                * Returns the key of the encountered error.
+                *
+                * @return The error key
+                */
+               public String getErrorKey() {
+                       return errorKey;
+               }
+
+               /**
+                * Returns whether the issue is fatal and the insert has to be
+                * aborted. Otherwise only a warning should be shown.
+                *
+                * @return {@code true} if the insert needs to be aborted, {@code
+                *         false} otherwise
+                */
+               public boolean isFatal() {
+                       return fatal;
+               }
+
+               /**
+                * Returns any additional parameters.
+                *
+                * @return The additional parameters
+                */
+               public String[] getParameters() {
+                       return parameters;
+               }
+
+       }
+
 }