Added ProcessLauncher and implementation.

src/main/java/net/rubygrapefruit/platform/ProcessLauncher.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012 Adam Murdoch
+ *
+ *    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 net.rubygrapefruit.platform;
+
+import java.lang.Process;
+
+/**
+ * Used to start processes, taking care of some platform-specific issues when launching processes concurrently or
+ * launching processes that will run in the background.
+ */
+@ThreadSafe
+public interface ProcessLauncher extends NativeIntegration {
+    /**
+     * Starts a process from the given settings.
+     *
+     * @param processBuilder The process settings.
+     * @return the process
+     * @throws NativeException On failure to start the process.
+     */
+    @ThreadSafe
+    Process start(ProcessBuilder processBuilder) throws NativeException;
+}

src/main/java/net/rubygrapefruit/platform/internal/DefaultProcessLauncher.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012 Adam Murdoch
+ *
+ *    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 net.rubygrapefruit.platform.internal;
+
+import net.rubygrapefruit.platform.NativeException;
+import net.rubygrapefruit.platform.ProcessLauncher;
+
+import java.io.IOException;
+
+public class DefaultProcessLauncher implements ProcessLauncher {
+    private final Object startLock = new Object();
+
+    public Process start(ProcessBuilder processBuilder) throws NativeException {
+        try {
+            synchronized (startLock) {
+                // Start a single process at a time, to avoid streams to child process being inherited by other
+                // children before the parent
+                return processBuilder.start();
+            }
+        } catch (IOException e) {
+            throw new NativeException(String.format("Could not start '%s'", processBuilder.command().get(0)), e);
+        }
+    }
+}

src/main/java/net/rubygrapefruit/platform/internal/Platform.java

@@ -131,6 +131,9 @@ public abstract class Platform {
             if (type.equals(Process.class)) {
                 return type.cast(new WrapperProcess(new DefaultProcess()));
             }
+            if (type.equals(ProcessLauncher.class)) {
+                return type.cast(new DefaultProcessLauncher());
+            }
             if (type.equals(Terminals.class)) {
                 nativeLibraryLoader.load(getCursesLibraryName());
                 int nativeVersion = TerminfoFunctions.getVersion();

src/test/groovy/net/rubygrapefruit/platform/ProcessLauncherTest.groovy

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012 Adam Murdoch
+ *
+ *    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 net.rubygrapefruit.platform
+
+import spock.lang.Specification
+
+class ProcessLauncherTest extends Specification {
+    final ProcessLauncher launcher = Native.get(ProcessLauncher)
+
+    def "can start a child process"() {
+        def javaHome = System.getProperty("java.home")
+        def exe = "${javaHome}/bin/java"
+        ProcessBuilder builder = new ProcessBuilder(exe, "-version")
+        builder.redirectErrorStream(true)
+
+        when:
+        def process = launcher.start(builder)
+        def stdout = new ByteArrayOutputStream()
+        def stdoutThread = process.consumeProcessOutputStream(stdout)
+        def result = process.waitFor()
+        stdoutThread.join()
+
+        then:
+        result == 0
+        stdout.toString().contains(System.getProperty('java.vm.version'))
+    }
+}