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Liquibase is a tool for managing and executing database changes.
package liquibase;
import liquibase.configuration.LiquibaseConfiguration;
import liquibase.database.Database;
import liquibase.database.DatabaseConnection;
import liquibase.database.OfflineConnection;
import liquibase.database.jvm.JdbcConnection;
import liquibase.exception.UnexpectedLiquibaseException;
import liquibase.listener.LiquibaseListener;
import liquibase.logging.LogService;
import liquibase.logging.Logger;
import liquibase.logging.core.JavaLogService;
import liquibase.logging.core.LogServiceFactory;
import liquibase.osgi.Activator;
import liquibase.resource.ClassLoaderResourceAccessor;
import liquibase.resource.ResourceAccessor;
import liquibase.servicelocator.ServiceLocator;
import liquibase.servicelocator.StandardServiceLocator;
import liquibase.ui.ConsoleUIService;
import liquibase.ui.UIService;
import liquibase.util.SmartMap;
import liquibase.util.StringUtil;
import java.lang.reflect.Constructor;
import java.nio.charset.Charset;
import java.util.*;
/**
* This scope object is used to hold configuration and other parameters within a call without needing complex method signatures.
* It also allows new parameters to be added by extensions without affecting standard method signatures.
* Scope objects can be created in a hierarchical manner with the {@link #child(Map, ScopedRunner)} or {@link #child(String, Object, ScopedRunner)} methods.
* Values set in parent scopes are visible in child scopes, but values in child scopes are not visible to parent scopes.
* Values with the same key in different scopes "mask" each other with the value furthest down the scope chain being returned.
*/
public class Scope {
/**
* Enumeration containing standard attributes. Normally use methods like convenience {@link #getResourceAccessor()} or {@link #getDatabase()}
*/
public enum Attr {
logService,
ui,
resourceAccessor,
classLoader,
database,
quotingStrategy,
changeLogHistoryService,
lockService,
executeMode,
lineSeparator,
serviceLocator,
/**
* @deprecated use {@link GlobalConfiguration#FILE_ENCODING}
*/
fileEncoding,
databaseChangeLog,
changeSet,
osgiPlatform
}
private static ScopeManager scopeManager;
private Scope parent;
private SmartMap values = new SmartMap();
private String scopeId;
private LiquibaseListener listener;
public static Scope getCurrentScope() {
if (scopeManager == null) {
scopeManager = new SingletonScopeManager();
}
if (scopeManager.getCurrentScope() == null) {
Scope rootScope = new Scope();
scopeManager.setCurrentScope(rootScope);
rootScope.values.put(Attr.logService.name(), new JavaLogService());
rootScope.values.put(Attr.resourceAccessor.name(), new ClassLoaderResourceAccessor());
rootScope.values.put(Attr.serviceLocator.name(), new StandardServiceLocator());
rootScope.values.put(Attr.ui.name(), new ConsoleUIService());
rootScope.getSingleton(LiquibaseConfiguration.class).init(rootScope);
LogService overrideLogService = rootScope.getSingleton(LogServiceFactory.class).getDefaultLogService();
if (overrideLogService == null) {
throw new UnexpectedLiquibaseException("Cannot find default log service");
}
rootScope.values.put(Attr.logService.name(), overrideLogService);
//check for higher-priority serviceLocator
ServiceLocator serviceLocator = rootScope.getServiceLocator();
for (ServiceLocator possibleLocator : serviceLocator.findInstances(ServiceLocator.class)) {
if (possibleLocator.getPriority() > serviceLocator.getPriority()) {
serviceLocator = possibleLocator;
}
}
rootScope.values.put(Attr.serviceLocator.name(), serviceLocator);
rootScope.values.put(Attr.osgiPlatform.name(), Activator.OSGIContainerChecker.isOsgiPlatform());
}
return scopeManager.getCurrentScope();
}
public static void setScopeManager(ScopeManager scopeManager) {
Scope currentScope = getCurrentScope();
if (currentScope == null) {
currentScope = new Scope();
}
try {
currentScope = scopeManager.init(currentScope);
} catch (Exception e) {
Scope.getCurrentScope().getLog(Scope.class).warning(e.getMessage(), e);
}
scopeManager.setCurrentScope(currentScope);
Scope.scopeManager = scopeManager;
}
/**
* Creates a new "root" scope.
* Defaults resourceAccessor to {@link ClassLoaderResourceAccessor}.
* Defaults serviceLocator to {@link StandardServiceLocator}
*/
private Scope() {
}
/**
* @param parent The new Scopes parent in the hierarchy of Scopes, not null.
* @param scopeValues The values for the new Scope.
*/
protected Scope(Scope parent, Map scopeValues) {
if (parent == null) {
throw new UnexpectedLiquibaseException("Cannot pass a null parent to a new Scope. Use Scope.child to correctly create a nested scope");
}
this.parent = parent;
if (scopeValues != null) {
for (Map.Entry entry : scopeValues.entrySet()) {
values.put(entry.getKey(), entry.getValue());
}
}
}
/**
* Returns the parent scope to this scope. Returns null if this is a root scope.
*/
public Scope getParent() {
return parent;
}
/**
* Creates a new scope that is a child of this scope.
*/
public static void child(Map scopeValues, ScopedRunner runner) throws Exception {
child((LiquibaseListener) null, scopeValues, runner);
}
/**
* Creates a new scope that is a child of this scope.
*/
public static ReturnType child(Map scopeValues, ScopedRunnerWithReturn runner) throws Exception {
return child(null, scopeValues, runner);
}
/**
* Creates a new child scope that includes the given {@link LiquibaseListener}.
* You cannot unassign a listener, they simply fall out of scope when the Scope does.
*
* @see #getListeners(Class)
*/
public static void child(LiquibaseListener listener, ScopedRunner runner) throws Exception {
child(listener, null, runner);
}
public static void child(LiquibaseListener listener, Map scopeValues, ScopedRunner runner) throws Exception {
child(listener, scopeValues, () -> {
runner.run();
return null;
});
}
public static T child(LiquibaseListener listener, Map scopeValues, ScopedRunnerWithReturn runner) throws Exception {
String scopeId = enter(listener, scopeValues);
try {
return runner.run();
} finally {
exit(scopeId);
}
}
/**
* Convenience version of {@link #enter(LiquibaseListener, Map)} with no {@link LiquibaseListener}
*/
public static String enter(Map scopeValues) throws Exception {
return enter(null, scopeValues);
}
/**
* Creates a new scope without passing a ScopedRunner.
* This mainly exists for tests where you have a setup/cleanup method pattern.
* The recommended way to create Scopes is the "child" methods.
* When done with the scope, call {@link #exit(String)}
*
* @return Returns the scopeId to pass to to {@link #exit(String)}
*/
public static String enter(LiquibaseListener listener, Map scopeValues) throws Exception {
String scopeId = StringUtil.randomIdentifer(10).toLowerCase();
Scope originalScope = getCurrentScope();
Scope child = new Scope(originalScope, scopeValues);
child.listener = listener;
child.scopeId = scopeId;
scopeManager.setCurrentScope(child);
return scopeId;
}
/**
* Exits the scope started with {@link #enter(LiquibaseListener, Map)}
*
* @param scopeId The id of the scope to exit. Throws an exception if the name does not match the current scope.
*/
public static void exit(String scopeId) throws Exception {
Scope currentScope = getCurrentScope();
if (!currentScope.scopeId.equals(scopeId)) {
throw new RuntimeException("Cannot end scope " + scopeId + " when currently at scope " + currentScope.scopeId);
}
scopeManager.setCurrentScope(currentScope.getParent());
}
/**
* Creates a new scope that is a child of this scope.
*/
public static void child(String newValueKey, Object newValue, ScopedRunner runner) throws Exception {
Map scopeValues = new HashMap();
scopeValues.put(newValueKey, newValue);
child(scopeValues, runner);
}
public static void child(Enum newValueKey, Object newValue, ScopedRunner runner) throws Exception {
child(newValueKey.name(), newValue, runner);
}
/**
* Return true if the given key is defined.
*/
public boolean has(String key) {
return get(key, Object.class) != null;
}
/**
* Return true if the given key is defined.
*/
public boolean has(Enum key) {
return has(key.name());
}
public T get(Enum key, Class type) {
return get(key.name(), type);
}
public T get(Enum key, T defaultValue) {
return get(key.name(), defaultValue);
}
/**
* Return the value associated with the given key in this scope or any parent scope.
* The value is converted to the given type if necessary using {@link liquibase.util.ObjectUtil#convert(Object, Class)}.
* Returns null if key is not defined in this or any parent scopes.
*/
public T get(String key, Class type) {
T value = values.get(key, type);
if (value == null && parent != null) {
value = parent.get(key, type);
}
return value;
}
/**
* Return the value associated with the given key in this scope or any parent scope.
* If the value is not defined, the passed defaultValue is returned.
* The value is converted to the given type if necessary using {@link liquibase.util.ObjectUtil#convert(Object, Class)}.
*/
public T get(String key, T defaultValue) {
Class type;
if (defaultValue == null) {
type = Object.class;
} else {
type = defaultValue.getClass();
}
Object value = get(key, type);
if (value == null) {
return defaultValue;
}
return (T) value;
}
/**
* Looks up the singleton object of the given type. If the singleton has not been created yet, it will be instantiated.
* The singleton is a singleton based on the root scope and the same object will be returned for all child scopes of the root.
*/
public T getSingleton(Class type) {
if (getParent() != null) {
return getParent().getSingleton(type);
}
String key = type.getName();
T singleton = get(key, type);
if (singleton == null) {
try {
try {
Constructor constructor = type.getDeclaredConstructor(Scope.class);
constructor.setAccessible(true);
singleton = constructor.newInstance(this);
} catch (NoSuchMethodException e) { //try without scope
Constructor constructor = type.getDeclaredConstructor();
constructor.setAccessible(true);
singleton = constructor.newInstance();
}
} catch (Exception e) {
throw new UnexpectedLiquibaseException(e);
}
values.put(key, singleton);
}
return singleton;
}
public Logger getLog(Class clazz) {
return get(Attr.logService, LogService.class).getLog(clazz);
}
public UIService getUI() {
return get(Attr.ui, UIService.class);
}
public Database getDatabase() {
return get(Attr.database, Database.class);
}
public ClassLoader getClassLoader() {
return get(Attr.classLoader, Thread.currentThread().getContextClassLoader());
}
public ClassLoader getClassLoader(boolean fallbackToContextClassLoader) {
ClassLoader classLoader = getClassLoader();
if (classLoader == null && fallbackToContextClassLoader) {
return Thread.currentThread().getContextClassLoader();
}
return classLoader;
}
public ServiceLocator getServiceLocator() {
return get(Attr.serviceLocator, ServiceLocator.class);
}
public ResourceAccessor getResourceAccessor() {
return get(Attr.resourceAccessor, ResourceAccessor.class);
}
public String getLineSeparator() {
return get(Attr.lineSeparator, System.lineSeparator());
}
/**
* @deprecated use {@link GlobalConfiguration#FILE_ENCODING}
*/
public Charset getFileEncoding() {
return get(Attr.fileEncoding, Charset.defaultCharset());
}
/**
* Returns {@link LiquibaseListener}s defined in this scope and/or all its parents that are of the given type.
*/
public Collection getListeners(Class type) {
List returnList = new ArrayList<>();
Scope scopeToCheck = this;
while (scopeToCheck != null) {
if (scopeToCheck.listener != null && type.isAssignableFrom(scopeToCheck.listener.getClass())) {
returnList.add((T) scopeToCheck.listener);
}
scopeToCheck = scopeToCheck.getParent();
}
return returnList;
}
@Override
public String toString() {
return describe();
}
public String describe() {
String databaseName = null;
Database database = getDatabase();
if (database != null) {
databaseName = database.getShortName();
DatabaseConnection connection = database.getConnection();
if (connection == null) {
databaseName = "unconnected " + databaseName;
} else if (connection instanceof OfflineConnection) {
databaseName = "offline " + databaseName;
} else if (connection instanceof JdbcConnection) {
databaseName = "jdbc " + databaseName;
}
}
return "scope(database=" + databaseName + ")";
}
public interface ScopedRunner {
void run() throws Exception;
}
public interface ScopedRunnerWithReturn {
T run() throws Exception;
}
}