SHL-174: Multi-Step Commands #67

AbstractStepExecutionProcessor.java

package org.springframework.shell.core;

import static java.util.logging.Level.SEVERE;

import java.util.logging.Logger;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.shell.core.annotation.CliStepIndicator;
import org.springframework.shell.event.ParseResult;
import org.springframework.shell.support.logging.HandlerUtils;


/**
 * An abstract custom {@link ExecutionProcessor} whose implementations can examine if the 
 * command being invoked has been annotated with @{@link CliStepIndicator} and, if so, 
 * handles, configures, executes, and displays each of the steps configured for the command.
 *  
 * @author robin
 */
public abstract class AbstractStepExecutionProcessor implements ExecutionProcessor {
	
	private static final Logger logger = HandlerUtils.getLogger(AbstractStepExecutionProcessor.class);
	
	@Autowired
	@Qualifier("shell")
	protected JLineShellComponent shell;
	
	private Object stepResult;
	private Object stepConfig;
	
	@Override
	public ParseResult beforeInvocation(ParseResult invocationContext) {
		return invocationContext;
	}
	
	@Override
	public void afterThrowingInvocation(ParseResult invocationContext, Throwable thrown) {
		logger.log(SEVERE, "Exception " + thrown.getMessage() + " thrown for " + invocationContext);
	}

	@Override
	public void afterReturningInvocation(ParseResult invocationContext, Object result) {
		// if the command being invoked supports steps...
		if (isStepCommand(invocationContext)) {			
			stepResult = result;
			
			// display the initial step result
			handleStepExecutionResult(invocationContext, stepResult);
			
			shell.setAlreadyHandledExecutionResult(true);
			
			// while there are more steps
			while (hasMoreSteps(stepResult)) {
				// configure the next step
				stepConfig = configureStep(stepResult);
				
				// execute the next step in the workflow
				stepResult = executeStep(stepResult, stepConfig);
				
				// display the step result
				handleStepExecutionResult(invocationContext, stepResult);
			}
		}
	}
	
	/**
	 * If the {@link CliStepIndicator} annotation is present, process the Step workflow
	 * 
	 * @param invocationContext
	 * @return
	 */
	protected final boolean isStepCommand(ParseResult invocationContext) {
		return invocationContext.getMethod().isAnnotationPresent(CliStepIndicator.class);		
	}

	/**
	 * Print the output of the current step execution
	 * @param invocationContext 
	 * @param stepResult 
	 */
	protected abstract void handleStepExecutionResult(ParseResult invocationContext, Object stepResult);
	
	/**
	 * Are there more steps to process
	 * @param stepResult 
	 * @return
	 */
	protected abstract boolean hasMoreSteps(Object stepResult);
	
	/**
	 * Use this method to control if/when and how the step will be processed
	 * @param stepResult 
	 * @return
	 */
	protected abstract Object configureStep(Object stepResult);
	
	/**
	 * Process the step using the stepConfig
	 * @param stepConfig
	 * @return
	 */
	protected abstract Object executeStep(Object stepResult, Object stepConfig); 

	/**
	 * @return the stepResult
	 */
	protected Object getStepResult() {
		return stepResult;
	}

	/**
	 * @return the stepConfig
	 */
	protected Object getStepConfig() {
		return stepConfig;
	}

}

StepCommand.java

package org.springframework.shell.commands;

import org.springframework.shell.core.AbstractStepExecutionProcessor;
import org.springframework.shell.core.annotation.CliCommand;
import org.springframework.shell.core.annotation.CliStepIndicator;
import org.springframework.shell.event.ParseResult;
import org.springframework.stereotype.Component;

/**
 * Multi-step commands to be tested
 *
 * @author robin
 */
@Component
public class StepCommand extends AbstractStepExecutionProcessor {
	
	private int steps = 0;
	
	@CliCommand(value={ "step-test"})
	@CliStepIndicator
	public Integer stepTest() {
		return steps;
	};
	
	@CliCommand(value={ "step-check"})
	public Integer stepCheck() {
		return steps;
	}

	/* (non-Javadoc)
	 * @see org.springframework.shell.core.AbstractStepExecutionProcessor#handleStepExecutionResult(org.springframework.shell.event.ParseResult, java.lang.Object)
	 */
	@Override
	protected void handleStepExecutionResult(ParseResult invocationContext, Object stepResult) {
		shell.getLogger().info("Step result: " + stepResult.toString());
	}

	/* (non-Javadoc)
	 * @see org.springframework.shell.core.AbstractStepExecutionProcessor#hasMoreSteps(java.lang.Object)
	 */
	@Override
	protected boolean hasMoreSteps(Object stepResult) {
		return steps < 3;
	}

	/* (non-Javadoc)
	 * @see org.springframework.shell.core.AbstractStepExecutionProcessor#configureStep(java.lang.Object)
	 */
	@Override
	protected Object configureStep(Object stepResult) {
		steps++;
		return null;
	}

	/* (non-Javadoc)
	 * @see org.springframework.shell.core.AbstractStepExecutionProcessor#executeStep(java.lang.Object, java.lang.Object)
	 */
	@Override
	protected Object executeStep(Object stepResult, Object stepConfig) {
		shell.getLogger().info("Executing step " + steps);
		return steps;
	}

}

StepCommandsTest.java

package org.springframework.shell.commands;

import org.hamcrest.MatcherAssert;
import org.hamcrest.Matchers;
import org.junit.Test;
import org.springframework.shell.core.CommandResult;
import org.springframework.shell.core.annotation.CliStepIndicator;

/**
 * Tests for commands annotated with @{@link CliStepIndicator}
 *
 * @author robin
 */
public class StepCommandsTest extends AbstractShellIntegrationTest {

	@Test
	public void command_withTwoSteps_StepCheckReportsCorrectCount() throws Exception {
		CommandResult cr = getShell().executeCommand("step-test");   
		String result = cr.getResult().toString();
		MatcherAssert.assertThat(result, Matchers.equalTo("0"));
		
		cr = getShell().executeCommand("step-check");   
		result = cr.getResult().toString();
		MatcherAssert.assertThat(result, Matchers.equalTo("3"));
	}
	
}