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Liquibase is a tool for managing and executing database changes.
package liquibase.command;
import liquibase.Scope;
import liquibase.SingletonObject;
import liquibase.servicelocator.ServiceLocator;
import liquibase.util.DependencyUtil;
import liquibase.util.StringUtil;
import java.lang.reflect.InvocationTargetException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;
/**
* Manages the command related implementations.
*/
public class CommandFactory implements SingletonObject {
private Collection allInstances;
/**
* A cache of all found command names and their corresponding command definition.
*/
private final Map commandDefinitions = new ConcurrentHashMap<>();
/**
* A cache of all found CommandStep classes and their corresponding override CommandStep.
*/
private Map, CommandStep> commandOverrides;
private final Map>> commandArgumentDefinitions = new HashMap<>();
/**
* @deprecated. Use {@link Scope#getSingleton(Class)}
*/
public static CommandFactory getInstance() {
return Scope.getCurrentScope().getSingleton(CommandFactory.class);
}
protected CommandFactory() {
}
/**
* Returns the complete {@link CommandDefinition} for the given commandName.
*
* @throws IllegalArgumentException if the commandName is not known
*/
public CommandDefinition getCommandDefinition(String... commandName) throws IllegalArgumentException{
CommandDefinition commandDefinition = commandDefinitions.get(commandName);
if (commandDefinition == null) { //Check if we have already computed arguments, dependencies, pipeline and adjusted definition
commandDefinition = new CommandDefinition(commandName);
computePipelineForCommandDefinition(commandDefinition);
consolidateCommandArgumentsForCommand(commandDefinition);
adjustCommandDefinitionForSteps(commandDefinition);
commandDefinitions.put(commandName, commandDefinition);
}
return commandDefinition;
}
/**
* Compute the pipeline for a given command. Takes into consideration all the dependencies required by the command
* and other commands subscribed to it by getOrder.
*
* @param commandDefinition the CommandDefinition to compute the pipeline
*/
private void computePipelineForCommandDefinition(CommandDefinition commandDefinition) {
final Set pipeline = new LinkedHashSet<>();
// graph used to automatically sort the pipeline steps.
DependencyUtil.DependencyGraph pipelineGraph = new DependencyUtil.DependencyGraph<>(
p -> { if (p != null) pipeline.add(p); }
);
Collection allCommandStepInstances = findAllInstances();
Map, CommandStep> overrides = findAllOverrides(allCommandStepInstances);
for (CommandStep step : allCommandStepInstances) {
// order > 0 means is means that this CommandStep has been declared as part of this command
if (step.getOrder(commandDefinition) > 0) {
Optional overrideStep = getOverride(overrides, step);
findDependenciesForCommand(pipelineGraph, allCommandStepInstances, overrideStep.orElse(step));
}
}
pipelineGraph.computeDependencies();
if (pipeline.isEmpty()) {
throw new IllegalArgumentException("Unknown command '" + StringUtil.join(commandDefinition.getName(), " ") + "'");
} else {
pipeline.forEach(p -> {
try {
commandDefinition.add(p.getClass().getConstructor().newInstance());
} catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
throw new IllegalArgumentException(e);
}
});
}
}
/**
* Given a CommandStep step this method adds to the pipelineGraph all the CommandSteps that are providing the dependencies that it requires.
*/
private void findDependenciesForCommand(DependencyUtil.DependencyGraph pipelineGraph, Collection allCommandStepInstances,
CommandStep step) {
if (step.requiredDependencies() == null || step.requiredDependencies().isEmpty()) {
pipelineGraph.add(null, step);
} else {
for (Class d : step.requiredDependencies()) {
CommandStep provider = whoProvidesClass(d, allCommandStepInstances);
pipelineGraph.add(provider, step);
findDependenciesForCommand(pipelineGraph, allCommandStepInstances, provider);
}
}
}
/**
* Go through all command steps and find the step that provides the desired class.
*/
private CommandStep whoProvidesClass(Class dependency, Collection allCommandStepInstances) {
return allCommandStepInstances.stream().filter(cs -> cs.providedDependencies() != null && cs.providedDependencies().contains(dependency))
.reduce((a, b) -> {
throw new IllegalStateException(String.format("More than one CommandStep provides class %s. Steps: %s, %s",
dependency.getName(), a.getClass().getName(), b.getClass().getName()));
})
.orElseThrow(() -> new IllegalStateException("Unable to find CommandStep provider for class " + dependency.getName()));
}
/**
* Go through all the commandSteps on the pipeline and add their arguments to the commandDefinition arguments list.
*/
private void consolidateCommandArgumentsForCommand(CommandDefinition commandDefinition) {
final Set> stepArguments = new HashSet<>();
for (CommandStep step : commandDefinition.getPipeline()) {
String[][] names = step.defineCommandNames();
if (names != null) {
for (String[] name : names) {
for (CommandArgumentDefinition command : this.commandArgumentDefinitions.getOrDefault(StringUtil.join(name, " "), new HashSet<>())) {
// uses the most specialized version of the argument, allowing overrides
stepArguments.stream().filter(cad -> cad.getName().equals(command.getName())).findAny()
.ifPresent(stepArguments::remove);
stepArguments.add(command);
}
}
}
}
if (!stepArguments.isEmpty()) {
for (CommandArgumentDefinition commandArg : stepArguments) {
commandDefinition.add(commandArg);
}
}
}
private void adjustCommandDefinitionForSteps(CommandDefinition commandDefinition) {
for (CommandStep step : commandDefinition.getPipeline()) {
step.adjustCommandDefinition(commandDefinition);
}
}
/**
* Returns all known {@link CommandDefinition}s.
*
* @param includeInternal if true, also include commands marked as {@link CommandDefinition#getInternal()}
*/
public SortedSet getCommands(boolean includeInternal) {
Map commandNames = new HashMap<>();
for (CommandStep step : findAllInstances()) {
String[][] names = step.defineCommandNames();
if (names != null) {
for (String[] name : names) {
commandNames.put(StringUtil.join(name, " "), name);
}
}
}
SortedSet commands = new TreeSet<>();
for (String[] commandName : commandNames.values()) {
try {
final CommandDefinition definition = getCommandDefinition(commandName);
if (includeInternal || !definition.getInternal()) {
commands.add(definition);
}
} catch (IllegalArgumentException e) {
//not a full command, like ConvertCommandStep
}
}
return Collections.unmodifiableSortedSet(commands);
}
/**
* Called by {@link CommandArgumentDefinition.Building#build()} to
* register that a particular {@link CommandArgumentDefinition} is available for a command.
*/
protected void register(String[] commandName, CommandArgumentDefinition definition) {
String commandNameKey = StringUtil.join(commandName, " ");
if (!commandArgumentDefinitions.containsKey(commandNameKey)) {
commandArgumentDefinitions.put(commandNameKey, new TreeSet<>());
}
if (commandArgumentDefinitions.get(commandNameKey).contains(definition)) {
throw new IllegalArgumentException("Duplicate argument '" + definition.getName() + "' found for command '" + commandNameKey + "'");
}
this.commandArgumentDefinitions.get(commandNameKey).add(definition);
}
/**
* Unregisters all information about the given {@link CommandStep}.
* package-protected method used primarily for testing and may be removed or modified in the future.
*/
protected void unregister(String[] commandName) {
commandArgumentDefinitions.remove(StringUtil.join(commandName, " "));
}
/**
* @deprecated use {@link #getCommandDefinition(String...)}
*/
public LiquibaseCommand getCommand(String commandName) {
return Scope.getCurrentScope().getSingleton(LiquibaseCommandFactory.class).getCommand(commandName);
}
/**
* @deprecated Use {@link CommandScope#execute()}
*/
public T execute(LiquibaseCommand command) throws CommandExecutionException {
command.validate();
try {
return command.run();
} catch (Exception e) {
if (e instanceof CommandExecutionException) {
throw (CommandExecutionException) e;
} else {
throw new CommandExecutionException(e);
}
}
}
//
// Find and cache all instances of CommandStep
//
private synchronized Collection findAllInstances() {
if (this.allInstances == null) {
this.allInstances = new ArrayList<>();
ServiceLocator serviceLocator = Scope.getCurrentScope().getServiceLocator();
this.allInstances.addAll(serviceLocator.findInstances(CommandStep.class));
}
return this.allInstances;
}
/**
* Find all commands that override other commands based on {@link CommandOverride#override()}.
* Validates that only a single command is overriding another.
* @param allCommandSteps all commands found during runtime
* @return a map with key of the CommandStep intended to override and value of the valid overriding command step
* @throws RuntimeException if more than one command step overrides another command step
*/
private Map, CommandStep> findAllOverrides(Collection allCommandSteps) throws RuntimeException {
if (commandOverrides == null) { //If we have not already found any overrides
Map, List> overrides = new HashMap<>();
allCommandSteps.stream()
.filter(commandStep -> commandStep.getClass().isAnnotationPresent(CommandOverride.class))
.forEach(overrideStep -> {
Class classToOverride = overrideStep.getClass().getAnnotation(CommandOverride.class).override();
overrides.computeIfAbsent(classToOverride, val -> new ArrayList<>()).add(overrideStep);
});
validateOverrides(overrides);
Map, CommandStep> validOverrides = new HashMap<>();
overrides.forEach((overriddenClass, validOverride) -> validOverride.stream().findFirst().ifPresent(valid -> validOverrides.put(overriddenClass, valid)));
this.commandOverrides = validOverrides;
}
return commandOverrides;
}
/**
* Validates that for all overrides, there is only a single override per command step. Logs all invalid overrides found.
* @param overrides the list of overrides
* @throws RuntimeException if more than one command step overrides a command step
*/
private void validateOverrides(Map, List> overrides) throws RuntimeException {
Map, List> invalidOverrides = new HashMap<>();
overrides.forEach((step, overrideSteps) -> {
if (overrideSteps.size() > 1) {
invalidOverrides.put(step, overrideSteps);
}
});
invalidOverrides.forEach((step, overrideSteps) -> {
Scope.getCurrentScope().getLog(getClass()).severe(String.format("Found multiple command steps overriding %s! A command may have at most one override. Invalid overrides include: %s",
step.getSimpleName(),
overrideSteps.stream().map(ovrr -> ovrr.getClass().getSimpleName()).collect(Collectors.joining(", "))));
});
if (!invalidOverrides.isEmpty()) {
throw new RuntimeException(String.format("Found more than one CommandOverride for CommandStep(s): %s! A command may have at most one override.", invalidOverrides.keySet().stream().map(Class::getSimpleName).collect(Collectors.joining(", "))));
}
}
/**
* Get the override for a given CommandStep.
* @param overrides the list of overrides
* @param step the step to check for overrides
* @return an optional containing the CommandStep override if present
*/
private Optional getOverride(Map, CommandStep> overrides, CommandStep step) {
CommandStep overrideStep = overrides.get(step.getClass());
if (overrideStep != null) {
if (overrideStep.getClass() != step.getClass()) {
Scope.getCurrentScope().getLog(getClass()).fine(String.format("Found %s override for %s! Using %s in pipeline.", overrideStep.getClass().getSimpleName(), step.getClass().getSimpleName(), overrideStep.getClass().getSimpleName()));
return Optional.of(overrideStep);
}
}
return Optional.empty();
}
}