/*
* Copyright 2006-2014 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.batch.core.job.flow.support;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.job.flow.Flow;
import org.springframework.batch.core.job.flow.FlowExecution;
import org.springframework.batch.core.job.flow.FlowExecutionException;
import org.springframework.batch.core.job.flow.FlowExecutionStatus;
import org.springframework.batch.core.job.flow.FlowExecutor;
import org.springframework.batch.core.job.flow.State;
import org.springframework.beans.factory.InitializingBean;
/**
* A {@link Flow} that branches conditionally depending on the exit status of
* the last {@link State}. The input parameters are the state transitions (in no
* particular order). The start state name can be specified explicitly (and must
* exist in the set of transitions), or computed from the existing transitions,
* if unambiguous.
*
* @author Dave Syer
* @author Michael Minella
* @since 2.0
*/
public class SimpleFlow implements Flow, InitializingBean {
private static final Log logger = LogFactory.getLog(SimpleFlow.class);
private State startState;
private Map<String, Set<StateTransition>> transitionMap = new HashMap<String, Set<StateTransition>>();
private Map<String, State> stateMap = new HashMap<String, State>();
private List<StateTransition> stateTransitions = new ArrayList<StateTransition>();
private final String name;
private Comparator<StateTransition> stateTransitionComparator;
public void setStateTransitionComparator(Comparator<StateTransition> stateTransitionComparator) {
this.stateTransitionComparator = stateTransitionComparator;
}
/**
* Create a flow with the given name.
*
* @param name the name of the flow
*/
public SimpleFlow(String name) {
this.name = name;
}
public State getStartState() {
return this.startState;
}
/**
* Get the name for this flow.
*
* @see Flow#getName()
*/
@Override
public String getName() {
return name;
}
/**
* Public setter for the stateTransitions.
*
* @param stateTransitions the stateTransitions to set
*/
public void setStateTransitions(List<StateTransition> stateTransitions) {
this.stateTransitions = stateTransitions;
}
/**
* {@inheritDoc}
*/
@Override
public State getState(String stateName) {
return stateMap.get(stateName);
}
/**
* {@inheritDoc}
*/
@Override
public Collection<State> getStates() {
return new HashSet<State>(stateMap.values());
}
/**
* Locate start state and pre-populate data structures needed for execution.
*
* @see InitializingBean#afterPropertiesSet()
*/
@Override
public void afterPropertiesSet() throws Exception {
if (startState == null) {
initializeTransitions();
}
}
/**
* @see Flow#start(FlowExecutor)
*/
@Override
public FlowExecution start(FlowExecutor executor) throws FlowExecutionException {
if (startState == null) {
initializeTransitions();
}
State state = startState;
String stateName = state.getName();
return resume(stateName, executor);
}
/**
* @see Flow#resume(String, FlowExecutor)
*/
@Override
public FlowExecution resume(String stateName, FlowExecutor executor) throws FlowExecutionException {
FlowExecutionStatus status = FlowExecutionStatus.UNKNOWN;
State state = stateMap.get(stateName);
logger.debug("Resuming state="+stateName+" with status="+status);
StepExecution stepExecution = null;
// Terminate if there are no more states
while (isFlowContinued(state, status, stepExecution)) {
stateName = state.getName();
try {
logger.debug("Handling state="+stateName);
status = state.handle(executor);
stepExecution = executor.getStepExecution();
}
catch (FlowExecutionException e) {
executor.close(new FlowExecution(stateName, status));
throw e;
}
catch (Exception e) {
executor.close(new FlowExecution(stateName, status));
throw new FlowExecutionException(String.format("Ended flow=%s at state=%s with exception", name,
stateName), e);
}
logger.debug("Completed state="+stateName+" with status="+status);
state = nextState(stateName, status, stepExecution);
}
FlowExecution result = new FlowExecution(stateName, status);
executor.close(result);
return result;
}
protected Map<String, Set<StateTransition>> getTransitionMap() {
return transitionMap;
}
protected Map<String, State> getStateMap() {
return stateMap;
}
/**
* @return the next {@link Step} (or null if this is the end)
* @throws org.springframework.batch.core.job.flow.FlowExecutionException
*/
protected State nextState(String stateName, FlowExecutionStatus status, StepExecution stepExecution) throws FlowExecutionException {
Set<StateTransition> set = transitionMap.get(stateName);
if (set == null) {
throw new FlowExecutionException(String.format("No transitions found in flow=%s for state=%s", getName(),
stateName));
}
String next = null;
String exitCode = status.getName();
for (StateTransition stateTransition : set) {
if (stateTransition.matches(exitCode) || (exitCode.equals("PENDING") && stateTransition.matches("STOPPED"))) {
if (stateTransition.isEnd()) {
// End of job
return null;
}
next = stateTransition.getNext();
break;
}
}
if (next == null) {
throw new FlowExecutionException(String.format("Next state not found in flow=%s for state=%s with exit status=%s", getName(), stateName, status.getName()));
}
if (!stateMap.containsKey(next)) {
throw new FlowExecutionException(String.format("Next state not specified in flow=%s for next=%s",
getName(), next));
}
return stateMap.get(next);
}
protected boolean isFlowContinued(State state, FlowExecutionStatus status, StepExecution stepExecution) {
boolean continued = true;
continued = state != null && status!=FlowExecutionStatus.STOPPED;
if(stepExecution != null) {
Boolean reRun = (Boolean) stepExecution.getExecutionContext().get("batch.restart");
Boolean executed = (Boolean) stepExecution.getExecutionContext().get("batch.executed");
if((executed == null || !executed) && reRun != null && reRun && status == FlowExecutionStatus.STOPPED && !state.getName().endsWith(stepExecution.getStepName()) ) {
continued = true;
}
}
return continued;
}
private boolean stateNameEndsWithStepName(State state, StepExecution stepExecution) {
return !(stepExecution == null || state == null) && !state.getName().endsWith(stepExecution.getStepName());
}
/**
* Analyse the transitions provided and generate all the information needed
* to execute the flow.
*/
private void initializeTransitions() {
startState = null;
transitionMap.clear();
stateMap.clear();
boolean hasEndStep = false;
if (stateTransitions.isEmpty()) {
throw new IllegalArgumentException("No start state was found. You must specify at least one step in a job.");
}
for (StateTransition stateTransition : stateTransitions) {
State state = stateTransition.getState();
String stateName = state.getName();
stateMap.put(stateName, state);
}
for (StateTransition stateTransition : stateTransitions) {
State state = stateTransition.getState();
if (!stateTransition.isEnd()) {
String next = stateTransition.getNext();
if (!stateMap.containsKey(next)) {
throw new IllegalArgumentException("Missing state for [" + stateTransition + "]");
}
}
else {
hasEndStep = true;
}
String name = state.getName();
Set<StateTransition> set = transitionMap.get(name);
if (set == null) {
// If no comparator is provided, we will maintain the order of insertion
if(stateTransitionComparator == null) {
set = new LinkedHashSet<StateTransition>();
} else {
set = new TreeSet<StateTransition>(stateTransitionComparator);
}
transitionMap.put(name, set);
}
set.add(stateTransition);
}
if (!hasEndStep) {
throw new IllegalArgumentException(
"No end state was found. You must specify at least one transition with no next state.");
}
startState = stateTransitions.get(0).getState();
}
}