Introduce a result interface to allow extraction of diagnostics

src/main/java/org/mdkt/compiler/CompilationResult.java

@@ -0,0 +1,40 @@
+package org.mdkt.compiler;
+
+import java.util.List;
+import java.util.Map;
+
+import javax.tools.Diagnostic;
+import javax.tools.JavaFileObject;
+
+public interface CompilationResult {
+	/**
+	 * Return the compiled classes
+	 */
+	Map<String, Class<?>> classMap() throws ClassNotFoundException;
+
+	/**
+	 * Determine if the compilation did succeed
+	 */
+	boolean compilationSucceeded();
+
+	/**
+	 * Determine if any warnings are present
+	 */
+	boolean hasWarnings();
+
+	/**
+	 * Determine if any errors are present
+	 */
+	boolean hasErrors();
+
+	/**
+	 * Return the diagnostics produced by the compiler
+	 */
+	List<Diagnostic<? extends JavaFileObject>> getDiagnostics();
+
+	/**
+	 * Throw an exception if the compilation did not succeed
+	 */
+	CompilationResult checkNoErrors();
+
+}

src/main/java/org/mdkt/compiler/InMemoryJavaCompiler.java

@@ -1,8 +1,18 @@
 package org.mdkt.compiler;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
 
-import javax.tools.*;
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticCollector;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.ToolProvider;
 
 /**
  * Compile Java sources in-memory
@@ -65,6 +75,14 @@ public InMemoryJavaCompiler ignoreWarnings() {
 	 * @throws Exception
 	 */
 	public Map<String, Class<?>> compileAll() throws Exception {
+		return compile().checkNoErrors().classMap();
+	}
+
+	/**
+	 * Compile all sources added until now and return {@link CompilationResult},
+	 * providing access to the compiled classes and/or errors and warnings
+	 */
+	public CompilationResult compile() throws Exception {
 		if (sourceCodes.size() == 0) {
 			throw new CompilationException("No source code to compile");
 		}
@@ -77,41 +95,84 @@ public Map<String, Class<?>> compileAll() throws Exception {
 			code[i] = new CompiledCode(iter.next().getClassName());
 		}
 		DiagnosticCollector<JavaFileObject> collector = new DiagnosticCollector<>();
-		ExtendedStandardJavaFileManager fileManager = new ExtendedStandardJavaFileManager(javac.getStandardFileManager(null, null, null), classLoader);
-		JavaCompiler.CompilationTask task = javac.getTask(null, fileManager, collector, options, null, compilationUnits);
-		boolean result = task.call();
-		if (!result || collector.getDiagnostics().size() > 0) {
-			StringBuffer exceptionMsg = new StringBuffer();
-			exceptionMsg.append("Unable to compile the source");
-			boolean hasWarnings = false;
-			boolean hasErrors = false;
+		ExtendedStandardJavaFileManager fileManager = new ExtendedStandardJavaFileManager(
+				javac.getStandardFileManager(null, null, null), classLoader);
+		JavaCompiler.CompilationTask task = javac.getTask(null, fileManager, collector, options, null,
+				compilationUnits);
+		task.call();
+		boolean hasWarnings;
+		boolean hasErrors;
+
+		{
+			boolean hasWarningsTmp = false;
+			boolean hasErrorsTmp = false;
 			for (Diagnostic<? extends JavaFileObject> d : collector.getDiagnostics()) {
 				switch (d.getKind()) {
 				case NOTE:
 				case MANDATORY_WARNING:
 				case WARNING:
-					hasWarnings = true;
+					hasWarningsTmp = true;
 					break;
 				case OTHER:
 				case ERROR:
 				default:
-					hasErrors = true;
+					hasErrorsTmp = true;
 					break;
 				}
-				exceptionMsg.append("\n").append("[kind=").append(d.getKind());
-				exceptionMsg.append(", ").append("line=").append(d.getLineNumber());
-				exceptionMsg.append(", ").append("message=").append(d.getMessage(Locale.US)).append("]");
-			}
-			if (hasWarnings && !ignoreWarnings || hasErrors) {
-				throw new CompilationException(exceptionMsg.toString());
 			}
+			hasWarnings = hasWarningsTmp;
+			hasErrors = hasErrorsTmp;
 		}
 
-		Map<String, Class<?>> classes = new HashMap<String, Class<?>>();
-		for (String className : sourceCodes.keySet()) {
-			classes.put(className, classLoader.loadClass(className));
-		}
-		return classes;
+		return new CompilationResult() {
+
+			@Override
+			public Map<String, Class<?>> classMap() throws ClassNotFoundException {
+				Map<String, Class<?>> classes = new HashMap<String, Class<?>>();
+				for (String className : sourceCodes.keySet()) {
+					classes.put(className, classLoader.loadClass(className));
+				}
+				return classes;
+			}
+
+			@Override
+			public boolean compilationSucceeded() {
+				if (hasWarnings && !ignoreWarnings)
+					return false;
+				return !hasErrors;
+			}
+
+			@Override
+			public boolean hasWarnings() {
+				return hasWarnings;
+			}
+
+			@Override
+			public boolean hasErrors() {
+				return hasErrors;
+			}
+
+			@Override
+			public List<Diagnostic<? extends JavaFileObject>> getDiagnostics() {
+				return collector.getDiagnostics();
+			}
+
+			@Override
+			public CompilationResult checkNoErrors() {
+				if (!compilationSucceeded()) {
+					StringBuffer exceptionMsg = new StringBuffer();
+					exceptionMsg.append("Unable to compile the source");
+					for (Diagnostic<? extends JavaFileObject> d : getDiagnostics()) {
+						exceptionMsg.append("\n").append("[kind=").append(d.getKind());
+						exceptionMsg.append(", ").append("line=").append(d.getLineNumber());
+						exceptionMsg.append(", ").append("message=").append(d.getMessage(Locale.US)).append("]");
+					}
+					throw new CompilationException(exceptionMsg.toString());
+				}
+				return this;
+			}
+
+		};
 	}
 
 	/**