Flow system for UI components

- Implement basic flow system with builder patterns
  to easily use components and hook those together
  as a flow.
- Fixes #364

Author: jvalkeal

spring-shell-core/src/main/java/org/springframework/shell/component/ConfirmationInput.java

@@ -63,7 +63,7 @@ public ConfirmationInput(Terminal terminal, String name, boolean defaultValue,
 	}
 
 	@Override
-	protected ConfirmationInputContext getThisContext(ComponentContext<?> context) {
+	public ConfirmationInputContext getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}

spring-shell-core/src/main/java/org/springframework/shell/component/MultiItemSelector.java

@@ -52,7 +52,7 @@ public MultiItemSelector(Terminal terminal, List<I> items, String name, Comparat
 	}
 
 	@Override
-	protected MultiItemSelectorContext<T, I> getThisContext(ComponentContext<?> context) {
+	public MultiItemSelectorContext<T, I> getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}

spring-shell-core/src/main/java/org/springframework/shell/component/PathInput.java

@@ -60,7 +60,7 @@ public PathInput(Terminal terminal, String name, Function<PathInputContext, List
 	}
 
 	@Override
-	protected PathInputContext getThisContext(ComponentContext<?> context) {
+	public PathInputContext getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}

spring-shell-core/src/main/java/org/springframework/shell/component/SingleItemSelector.java

@@ -52,7 +52,7 @@ public SingleItemSelector(Terminal terminal, List<I> items, String name, Compara
 	}
 
 	@Override
-	protected SingleItemSelectorContext<T, I> getThisContext(ComponentContext<?> context) {
+	public SingleItemSelectorContext<T, I> getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}

spring-shell-core/src/main/java/org/springframework/shell/component/StringInput.java

@@ -68,7 +68,7 @@ public void setMaskCharater(Character maskCharacter) {
 	}
 
 	@Override
-	protected StringInputContext getThisContext(ComponentContext<?> context) {
+	public StringInputContext getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}

spring-shell-core/src/main/java/org/springframework/shell/component/flow/BaseConfirmationInput.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2022 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
+ *
+ *      https://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.component.flow;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+import org.jline.utils.AttributedString;
+
+import org.springframework.shell.component.ConfirmationInput.ConfirmationInputContext;
+import org.springframework.shell.component.flow.ComponentFlow.BaseBuilder;
+import org.springframework.shell.component.flow.ComponentFlow.Builder;
+
+/**
+ * Base impl for {@link ConfirmationInputSpec}.
+ *
+ * @author Janne Valkealahti
+ */
+public abstract class BaseConfirmationInput extends BaseInput<ConfirmationInputSpec> implements ConfirmationInputSpec {
+
+	private String name;
+	private Boolean defaultValue;
+	private Function<ConfirmationInputContext, List<AttributedString>> renderer;
+	private List<Consumer<ConfirmationInputContext>> preHandlers = new ArrayList<>();
+	private List<Consumer<ConfirmationInputContext>> postHandlers = new ArrayList<>();
+	private boolean storeResult = true;
+	private String templateLocation;
+	private Function<ConfirmationInputContext, String> next;
+
+	public BaseConfirmationInput(BaseBuilder builder, String id) {
+		super(builder, id);
+	}
+
+	@Override
+	public ConfirmationInputSpec name(String name) {
+		this.name = name;
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec defaultValue(Boolean defaultValue) {
+		this.defaultValue = defaultValue;
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec renderer(Function<ConfirmationInputContext, List<AttributedString>> renderer) {
+		this.renderer = renderer;
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec template(String location) {
+		this.templateLocation = location;
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec preHandler(Consumer<ConfirmationInputContext> handler) {
+		this.preHandlers.add(handler);
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec postHandler(Consumer<ConfirmationInputContext> handler) {
+		this.postHandlers.add(handler);
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec storeResult(boolean store) {
+		this.storeResult = store;
+		return this;
+	}
+
+	@Override
+	public ConfirmationInputSpec next(Function<ConfirmationInputContext, String> next) {
+		this.next = next;
+		return this;
+	}
+
+	@Override
+	public Builder and() {
+		getBuilder().addConfirmationInput(this);
+		return getBuilder();
+	}
+
+	@Override
+	public ConfirmationInputSpec getThis() {
+		return this;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public boolean getDefaultValue() {
+		return defaultValue != null ? defaultValue : true;
+	}
+
+	public Function<ConfirmationInputContext, List<AttributedString>> getRenderer() {
+		return renderer;
+	}
+
+	public String getTemplateLocation() {
+		return templateLocation;
+	}
+
+	public List<Consumer<ConfirmationInputContext>> getPreHandlers() {
+		return preHandlers;
+	}
+
+	public List<Consumer<ConfirmationInputContext>> getPostHandlers() {
+		return postHandlers;
+	}
+
+	public boolean isStoreResult() {
+		return storeResult;
+	}
+
+	public Function<ConfirmationInputContext, String> getNext() {
+		return next;
+	}
+}

spring-shell-core/src/main/java/org/springframework/shell/component/flow/BaseInput.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2022 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
+ *
+ *      https://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.component.flow;
+
+import org.springframework.core.Ordered;
+import org.springframework.shell.component.flow.ComponentFlow.BaseBuilder;
+
+/**
+ * Base impl for specs.
+ *
+ * @author Janne Valkealahti
+ */
+public abstract class BaseInput<T extends BaseInputSpec<T>> implements Ordered, BaseInputSpec<T> {
+
+	private final BaseBuilder builder;
+	private final String id;
+	private int order;
+
+	BaseInput(BaseBuilder builder, String id) {
+		this.builder = builder;
+		this.id = id;
+	}
+
+	@Override
+	public int getOrder() {
+		return order;
+	}
+
+	public void setOrder(int order) {
+		this.order = order;
+	}
+
+	@Override
+	public T order(int order) {
+		this.order = order;
+		return getThis();
+	}
+
+	public BaseBuilder getBuilder() {
+		return builder;
+	}
+
+	public String getId() {
+		return id;
+	}
+}

spring-shell-core/src/main/java/org/springframework/shell/component/flow/BaseInputSpec.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2022 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
+ *
+ *      https://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.component.flow;
+
+/**
+ * Base spec for other specs.
+ *
+ * @author Janne Valkealahti
+ */
+public interface BaseInputSpec<T extends BaseInputSpec<T>> {
+
+	/**
+	 * Sets order of this component.
+	 *
+	 * @param order the order
+	 * @return a builder
+	 */
+	T order(int order);
+
+	/**
+	 * Usual this trick to get typed child.
+	 *
+	 * @return a builder
+	 */
+	T getThis();
+}