Add a target handler.

src/de/inetsoftware/jwebassembly/JWebAssembly.java

@@ -36,6 +36,7 @@ import de.inetsoftware.classparser.ClassFile;
 import de.inetsoftware.jwebassembly.binary.BinaryModuleWriter;
 import de.inetsoftware.jwebassembly.module.ModuleGenerator;
 import de.inetsoftware.jwebassembly.module.ModuleWriter;
+import de.inetsoftware.jwebassembly.module.WasmTarget;
 import de.inetsoftware.jwebassembly.text.TextModuleWriter;
 
 /**
@@ -225,8 +226,8 @@ public class JWebAssembly {
      *             if any conversion error occurs
      */
     public void compileToBinary( File file ) throws WasmException {
-        try (OutputStream output = new BufferedOutputStream( new FileOutputStream( file ) )) {
+        try (WasmTarget target = new WasmTarget( file ) ) {
-            compileToBinary( output );
+            compileToBinary( target );
         } catch( Exception ex ) {
             throw WasmException.create( ex );
         }
@@ -241,7 +242,23 @@ public class JWebAssembly {
      *             if any conversion error occurs
      */
     public void compileToBinary( OutputStream output ) throws WasmException {
-        try (BinaryModuleWriter writer = new BinaryModuleWriter( output, properties )) {
+        try (WasmTarget target = new WasmTarget( output )) {
+            compileToBinary( target );
+        } catch( Exception ex ) {
+            throw WasmException.create( ex );
+        }
+    }
+
+    /**
+     * Convert the added files to a WebAssembly module in binary representation.
+     * 
+     * @param target
+     *            the target for the module data
+     * @throws WasmException
+     *             if any conversion error occurs
+     */
+    private void compileToBinary( WasmTarget target ) throws WasmException {
+        try (BinaryModuleWriter writer = new BinaryModuleWriter( target, properties )) {
             compile( writer );
         } catch( Exception ex ) {
             throw WasmException.create( ex );

src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java

@@ -16,7 +16,6 @@
 package de.inetsoftware.jwebassembly.binary;
 
 import java.io.IOException;
-import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -34,10 +33,11 @@ import de.inetsoftware.jwebassembly.JWebAssembly;
 import de.inetsoftware.jwebassembly.module.FunctionName;
 import de.inetsoftware.jwebassembly.module.ModuleWriter;
 import de.inetsoftware.jwebassembly.module.ValueTypeConvertion;
+import de.inetsoftware.jwebassembly.module.WasmTarget;
+import de.inetsoftware.jwebassembly.wasm.AnyType;
 import de.inetsoftware.jwebassembly.wasm.ArrayOperator;
 import de.inetsoftware.jwebassembly.wasm.NamedStorageType;
 import de.inetsoftware.jwebassembly.wasm.NumericOperator;
-import de.inetsoftware.jwebassembly.wasm.AnyType;
 import de.inetsoftware.jwebassembly.wasm.StructOperator;
 import de.inetsoftware.jwebassembly.wasm.ValueType;
 import de.inetsoftware.jwebassembly.wasm.VariableOperator;
@@ -54,6 +54,8 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
 
     private static final int            WASM_BINARY_VERSION = 1;
 
+    private WasmTarget                  target;
+
     private WasmOutputStream            wasm;
 
     private final boolean               debugNames;
@@ -90,8 +92,8 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
      * @throws IOException
      *             if any I/O error occur
      */
-    public BinaryModuleWriter( OutputStream output, HashMap<String, String> properties ) throws IOException {
+    public BinaryModuleWriter( WasmTarget target, HashMap<String, String> properties ) throws IOException {
-        wasm = new WasmOutputStream( output );
+        this.target = target;
         // for now we build the source map together with debug names
         debugNames = createSourceMap = Boolean.parseBoolean( properties.get( JWebAssembly.DEBUG_NAMES ) );
     }
@@ -101,6 +103,7 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
      */
     @Override
     public void close() throws IOException {
+        wasm = new WasmOutputStream( target.getWasmOutput() );
         wasm.write( WASM_BINARY_MAGIC );
         wasm.writeInt32( WASM_BINARY_VERSION );
 

src/de/inetsoftware/jwebassembly/module/WasmTarget.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2019 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly.module;
+
+import java.io.BufferedOutputStream;
+import java.io.Closeable;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+import javax.annotation.Nonnull;
+
+/**
+ * The target for the different outputs
+ */
+public class WasmTarget implements Closeable {
+
+    private File         file;
+
+    private OutputStream output;
+
+    /**
+     * Create a target with a file.
+     * 
+     * @param file
+     *            the wasm file
+     */
+    public WasmTarget( File file ) {
+        this.file = file;
+    }
+
+    /**
+     * Create a target with an OutputStream
+     * 
+     * @param output
+     *            the stream for the wasm file
+     */
+    public WasmTarget( OutputStream output ) {
+        this.output = output;
+    }
+
+    /**
+     * Get the wasm OutputStream
+     * 
+     * @return the stream
+     * @throws IOException
+     *             if any I/O error occur
+     */
+    @Nonnull
+    public OutputStream getWasmOutput() throws IOException {
+        if( output == null ) {
+            output = new BufferedOutputStream( new FileOutputStream( file ) );
+        }
+        return output;
+    }
+
+    /**
+     * Close all streams
+     * 
+     * @throws IOException
+     *             if any I/O error occur
+     */
+    @Override
+    public void close() throws IOException {
+        output.close();
+    }
+}