Make ResultHandlers configuration more explicit

Handle exit as a dedicated case (prevents eg 'exit' commands in scripts to make script quit)
Add an example of custom ApplicationRunner

Fixes #187
Fixes #183

Decouple ApplicationRunners

Make ThrowableResultHandler behave differently in non-interactive mode

spring-shell-samples/src/main/java/org/springframework/shell/samples/ExampleApplicationRunnerConfiguration.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * 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 org.springframework.shell.samples;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.ExitCodeExceptionMapper;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.shell.ExitRequest;
+import org.springframework.shell.Input;
+import org.springframework.shell.InputProvider;
+import org.springframework.shell.Shell;
+import org.springframework.shell.jline.InteractiveShellApplicationRunner;
+import org.springframework.util.StringUtils;
+
+@Configuration
+public class ExampleApplicationRunnerConfiguration {
+
+	@Autowired
+	private Shell shell;
+
+	@Bean
+	public CommandLineRunner exampleCommandLineRunner(ConfigurableEnvironment environment) {
+		return new ExampleCommandLineRunner(shell, environment);
+	}
+
+	@Bean
+	public ExitCodeExceptionMapper exitCodeExceptionMapper() {
+		return exception -> {
+			Throwable e = exception;
+			while (e != null && !(e instanceof ExitRequest)) {
+				e = e.getCause();
+			}
+			return e == null ? 1 : ((ExitRequest) e).status();
+		};
+	}
+}
+
+/**
+ * Example CommandLineRunner that shows how overall shell behavior can be customized. In
+ * this particular example, any program (process) arguments are assumed to be shell
+ * commands that need to be executed (and the shell then quits).
+ */
+@Order(InteractiveShellApplicationRunner.PRECEDENCE - 2)
+class ExampleCommandLineRunner implements CommandLineRunner {
+
+	private Shell shell;
+
+	private final ConfigurableEnvironment environment;
+
+	public ExampleCommandLineRunner(Shell shell, ConfigurableEnvironment environment) {
+		this.shell = shell;
+		this.environment = environment;
+	}
+
+	@Override
+	public void run(String... args) throws Exception {
+		List<String> commandsToRun = Arrays.stream(args)
+				.filter(w -> !w.startsWith("@"))
+				.collect(Collectors.toList());
+		if (!commandsToRun.isEmpty()) {
+			InteractiveShellApplicationRunner.disable(environment);
+			shell.run(new StringInputProvider(commandsToRun));
+		}
+	}
+}
+
+class StringInputProvider implements InputProvider {
+
+	private final List<String> words;
+
+	private boolean done;
+
+	public StringInputProvider(List<String> words) {
+		this.words = words;
+	}
+
+	@Override
+	public Input readInput() {
+		if (!done) {
+			done = true;
+			return new Input() {
+				@Override
+				public List<String> words() {
+					return words;
+				}
+
+				@Override
+				public String rawText() {
+					return StringUtils.collectionToDelimitedString(words, " ");
+				}
+			};
+		}
+		else {
+			return null;
+		}
+	}
+}