Include error log in CompilationException/TranslationException

src/main/java/org/liblouis/CompilationException.java

@@ -1,17 +1,32 @@
 package org.liblouis;
 
+import java.util.List;
+
 @SuppressWarnings("serial")
 public class CompilationException extends Exception {
 
 	public CompilationException(String message) {
 		super(message);
 	}
 
+	public CompilationException(String message, List<String> errors) {
+		this(addErrorsToMessage(message, errors));
+	}
+
 	public CompilationException(Throwable cause) {
 		super(cause);
 	}
 
 	public CompilationException(String message, Throwable cause) {
 		super(message, cause);
 	}
+
+	private static String addErrorsToMessage(String message, List<String> errors) {
+		if (errors != null && !errors.isEmpty()) {
+			message += "\nErrors:";
+			for (String e : errors)
+				message += ("\n" + e);
+		}
+		return message;
+	}
 }

src/main/java/org/liblouis/Louis.java

@@ -8,9 +8,11 @@
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.file.Files;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -136,11 +138,22 @@ private File[] _invoke(String table, File base) {
 	private static Lou_LogCallback lou_logCallback = null;
 	private static boolean loggerIsRegistered = false;
 
+	// capture errors so that Translator can include them in CompilationException or TranslationException
+	static List<String> errors = new ArrayList<>();
+
 	public static synchronized void setLogger(final Logger logger) {
 		logCallback = logger;
 		lou_logCallback = new Lou_LogCallback() {
 			public void invoke(int level, String message) {
-				logger.log(Logger.Level.from(level), message);
+				Logger.Level lvl = Logger.Level.from(level);
+				switch (lvl) {
+				case ERROR:
+				case FATAL:
+					errors.add(message);
+					break;
+				}
+				if (logger != null)
+					logger.log(lvl, message);
 			}
 		};
 		loggerIsRegistered = false;

src/main/java/org/liblouis/TranslationException.java

@@ -1,11 +1,17 @@
 package org.liblouis;
 
+import java.util.List;
+
 @SuppressWarnings("serial")
 public class TranslationException extends Exception {
 
 	public TranslationException(String message) {
 		super(message);
 	}
+
+	public TranslationException(String message, List<String> errors) {
+		this(addErrorsToMessage(message, errors));
+	}
 
 	public TranslationException(Throwable throwable) {
 		super(throwable);
@@ -14,4 +20,13 @@ public TranslationException(Throwable throwable) {
 	public TranslationException(String message, Throwable throwable) {
 		super(message, throwable);
 	}
+
+	private static String addErrorsToMessage(String message, List<String> errors) {
+		if (errors != null && !errors.isEmpty()) {
+			message += "\nErrors:";
+			for (String e : errors)
+				message += ("\n" + e);
+		}
+		return message;
+	}
 }

src/main/java/org/liblouis/Translator.java

@@ -33,8 +33,11 @@ public class Translator {
 	 */
 	public Translator(String table) throws CompilationException {
 		Louis.log(Logger.Level.DEBUG, "Loading table %s", table);
-		if (Louis.getLibrary().lou_getTable(table) == Pointer.NULL)
-			throw new CompilationException("Unable to compile table '" + table + "'");
+		synchronized (Louis.errors) {
+			Louis.errors.clear();
+			if (Louis.getLibrary().lou_getTable(table) == Pointer.NULL)
+				throw new CompilationException("Unable to compile table '" + table + "'", Louis.errors);
+		}
 		this.table = table;
 	}
 
@@ -45,8 +48,11 @@ public Translator(String table) throws CompilationException {
 	public Translator(URL table) throws CompilationException {
 		Louis.log(Logger.Level.DEBUG, "Loading table %s", table);
 		this.table = Louis.getTableNameForURL(table);
-		if (Louis.getLibrary().lou_getTable(this.table) == Pointer.NULL)
-			throw new CompilationException("Unable to compile table '" + table + "'");
+		synchronized (Louis.errors) {
+			Louis.errors.clear();
+			if (Louis.getLibrary().lou_getTable(this.table) == Pointer.NULL)
+				throw new CompilationException("Unable to compile table '" + table + "'", Louis.errors);
+		}
 	}
 
 	/**
@@ -192,9 +198,12 @@ private TranslationResult translate(String text,
 		if (characterAttributes != null || interCharacterAttributes != null)
 			inputPos = getIntegerBuffer("inputpos", textLength * OUTLEN_MULTIPLIER);
 		int mode = displayTable.getMode().value();
-		if (Louis.getLibrary().lou_translate(table, inbuf, inlen, outbuf, outlen, typeform,
-		                                     null, null, inputPos, null, mode) == 0)
-			throw new TranslationException("Unable to complete translation");
+		synchronized (Louis.errors) {
+			Louis.errors.clear();
+			if (Louis.getLibrary().lou_translate(table, inbuf, inlen, outbuf, outlen, typeform,
+			                                     null, null, inputPos, null, mode) == 0)
+				throw new TranslationException("Unable to complete translation", Louis.errors);
+		}
 		return new TranslationResult(outbuf, outlen, inputPos, characterAttributes, interCharacterAttributes, displayTable);
 	}
 
@@ -210,10 +219,12 @@ public String backTranslate(String text) throws TranslationException {
 		WideCharString outbuf = getWideCharBuffer("text-out", textLength * OUTLEN_MULTIPLIER);
 		IntByReference inlen = new IntByReference(textLength);
 		IntByReference outlen = new IntByReference(outbuf.length());
-
-		if (Louis.getLibrary().lou_backTranslate(table, inbuf, inlen, outbuf, outlen,
-				null, null, null, null, null, 0) == 0)
-			throw new TranslationException("Unable to complete translation");
+		synchronized (Louis.errors) {
+			Louis.errors.clear();
+			if (Louis.getLibrary().lou_backTranslate(table, inbuf, inlen, outbuf, outlen,
+					null, null, null, null, null, 0) == 0)
+				throw new TranslationException("Unable to complete translation", Louis.errors);
+		}
 		try {
 			return outbuf.read(outlen.getValue()); }
 		catch (IOException e) {
@@ -251,8 +262,11 @@ public byte[] hyphenate(String text) throws TranslationException {
 		while (matcher.find()) {
 			int start = matcher.start();
 			int end = matcher.end();
-			if (louis.lou_hyphenate(table, inbuf.substring(start), end - start, wordHyphens, 0) == 0)
-				throw new TranslationException("Unable to complete hyphenation");
+			synchronized (Louis.errors) {
+				Louis.errors.clear();
+				if (louis.lou_hyphenate(table, inbuf.substring(start), end - start, wordHyphens, 0) == 0)
+					throw new TranslationException("Unable to complete hyphenation", Louis.errors);
+			}
 			for (int i = 0; i < end - start; i++) hyphens[start + i] = wordHyphens[i]; }
 
 		byte[] hyphenPositions = readHyphens(new byte[inlen - 1], hyphens);