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Liquibase is a tool for managing and executing database changes.
package liquibase.change.custom;
import liquibase.Scope;
import liquibase.change.*;
import liquibase.database.Database;
import liquibase.exception.*;
import liquibase.parser.core.ParsedNode;
import liquibase.parser.core.ParsedNodeException;
import liquibase.resource.ResourceAccessor;
import liquibase.statement.SqlStatement;
import liquibase.util.ObjectUtil;
import java.util.*;
import liquibase.util.OsgiUtil;
/**
* Adapts CustomChange implementations to the standard change system used by Liquibase.
* Custom change implementations should implement CustomSqlChange or CustomTaskChange
*
* @see liquibase.change.custom.CustomSqlChange
* @see liquibase.change.custom.CustomTaskChange
*/
@DatabaseChange(name="customChange",
description = "Although Liquibase tries to provide a wide range of database refactorings, there are times you may" +
" want to create your own custom refactoring class.\n" +
"\n" +
"To create your own custom refactoring, simply create a class that implements the liquibase.change.custom.CustomSqlChange " +
"or liquibase.change.custom.CustomTaskChange interface and use the tag in your changeset.\n" +
"\n" +
"If your change can be rolled back, implement the liquibase.change.custom.CustomSqlRollback interface as well.\n" +
"\n" +
"For a sample custom change class, see liquibase.change.custom.ExampleCustomSqlChange",
priority = ChangeMetaData.PRIORITY_DEFAULT)
public class CustomChangeWrapper extends AbstractChange {
/**
* Non-private access only for testing.
*/
CustomChange customChange;
private String className;
private SortedSet params = new TreeSet<>();
private Map paramValues = new LinkedHashMap<>();
private boolean configured;
@Override
public boolean generateStatementsVolatile(Database database) {
return true;
}
/**
* Return the CustomChange instance created by the call to {@link #setClass(String)}.
*/
@DatabaseChangeProperty(isChangeProperty = false)
public CustomChange getCustomChange() {
return customChange;
}
/**
* Specify the name of the class to use as the CustomChange and assigns it to {@link #getCustomChange()}.
*/
public CustomChangeWrapper setClass(String className) throws CustomChangeException {
if (className == null) {
return this;
}
this.className = className;
try {
Boolean osgiPlatform = Scope.getCurrentScope().get(Scope.Attr.osgiPlatform, Boolean.class);
if (Boolean.TRUE.equals(osgiPlatform)) {
customChange = (CustomChange)OsgiUtil.loadClass(className).getConstructor().newInstance();
} else {
try {
customChange = (CustomChange) Class.forName(className, true, Scope.getCurrentScope().getClassLoader()).getConstructor().newInstance();
} catch (ClassCastException e) { //fails in Ant in particular
try {
customChange = (CustomChange) Thread.currentThread().getContextClassLoader().loadClass(className).getConstructor().newInstance();
} catch (ClassNotFoundException e1) {
customChange = (CustomChange) Class.forName(className).getConstructor().newInstance();
}
}
}
} catch (Exception e) {
throw new CustomChangeException(e);
}
return this;
}
/**
* Returns the name of the custom class set in {@link #setClass(String)}
*/
@DatabaseChangeProperty(description = "Name class that implements the custom change.")
public String getClassName() {
return className;
}
/**
* Specify a parameter on the CustomChange object to set before executing {@link liquibase.change.Change#generateStatements(liquibase.database.Database)} or {@link #generateRollbackStatements(liquibase.database.Database)} on it.
* The CustomChange class must have a set method for the given parameter. For example, to call setParam("lastName", "X") you must have a method setLastName(String val) on your class.
*/
public void setParam(String name, String value) {
this.params.add(name);
this.paramValues.put(name, value);
}
/**
* Returns the parameters set by {@link #setParam(String, String)}. If no parameters are set, an empty set will be returned
*/
@DatabaseChangeProperty(isChangeProperty = false)
public SortedSet getParams() {
return Collections.unmodifiableSortedSet(params);
}
/**
* Get the value of a parameter set by {@link #setParam(String, String)}. If the parameter was not set, null will be returned.
*/
public String getParamValue(String key) {
return paramValues.get(key);
}
/**
* Call the {@link CustomChange#validate(liquibase.database.Database)} method and return the result.
*/
@Override
public ValidationErrors validate(Database database) {
if (!configured) {
try {
configureCustomChange();
} catch (CustomChangeException e) {
throw new UnexpectedLiquibaseException(e);
}
}
try {
return customChange.validate(database);
} catch (Exception e) {
return new ValidationErrors().addError("Exception thrown calling "+getClassName()+".validate():"+ e.getMessage());
}
}
/**
* Required for the Change interface, but not supported by CustomChanges. Returns an empty Warnings object.
*/
@Override
public Warnings warn(Database database) {
//does not support warns
return new Warnings();
}
/**
* Finishes configuring the CustomChange based on the values passed to {@link #setParam(String, String)} then calls {@link CustomSqlChange#generateStatements(liquibase.database.Database)}
* or {@link CustomTaskChange#execute(liquibase.database.Database)} depending on the CustomChange implementation.
*
* If the CustomChange returns a null SqlStatement array, this method returns an empty array. If a CustomTaskChange is being used, this method will return an empty array.
*/
@Override
public SqlStatement[] generateStatements(Database database) {
SqlStatement[] statements = null;
if (shouldExecuteChange(database)) {
try {
configureCustomChange();
if (customChange instanceof CustomSqlChange) {
statements = ((CustomSqlChange) customChange).generateStatements(database);
} else if (customChange instanceof CustomTaskChange) {
((CustomTaskChange) customChange).execute(database);
} else {
throw new UnexpectedLiquibaseException(customChange.getClass().getName() + " does not implement " + CustomSqlChange.class.getName() + " or " + CustomTaskChange.class.getName());
}
} catch (CustomChangeException e) {
throw new UnexpectedLiquibaseException(e);
}
}
if (statements == null) {
statements = SqlStatement.EMPTY_SQL_STATEMENT;
}
return statements;
}
/**
* Finishes configuring the CustomChange based on the values passed to {@link #setParam(String, String)} then calls {@link CustomSqlRollback#generateRollbackStatements(liquibase.database.Database)}
* or {@link CustomTaskRollback#rollback(liquibase.database.Database)} depending on the CustomChange implementation.
*
* If the CustomChange returns a null SqlStatement array, this method returns an empty array. If a CustomTaskChange is being used, this method will return an empty array.
* Any {@link RollbackImpossibleException} exceptions thrown by the CustomChange will thrown by this method.
*/
@Override
public SqlStatement[] generateRollbackStatements(Database database) throws RollbackImpossibleException {
SqlStatement[] statements = null;
try {
configureCustomChange();
if (customChange instanceof CustomSqlRollback) {
statements = ((CustomSqlRollback) customChange).generateRollbackStatements(database);
} else if (customChange instanceof CustomTaskRollback) {
((CustomTaskRollback) customChange).rollback(database);
} else {
throw new RollbackImpossibleException("Unknown rollback type: "+customChange.getClass().getName());
}
} catch (CustomChangeException e) {
throw new UnexpectedLiquibaseException(e);
}
if (statements == null) {
statements = SqlStatement.EMPTY_SQL_STATEMENT;
}
return statements;
}
/**
* Returns true if the customChange supports rolling back.
* {@link #generateRollbackStatements} may still throw a {@link RollbackImpossibleException} when it is actually executed, even if this method returns true.
* Currently only checks if the customChange implements {@link CustomSqlRollback}
*/
@Override
public boolean supportsRollback(Database database) {
return (customChange instanceof CustomSqlRollback) || (customChange instanceof CustomTaskRollback);
}
/**
* Return the customChange's {@link CustomChange#getConfirmationMessage} message as the Change's message.
*/
@Override
public String getConfirmationMessage() {
try {
configureCustomChange();
} catch (CustomChangeException e) {
throw new UnexpectedLiquibaseException(e);
}
return customChange.getConfirmationMessage();
}
private void configureCustomChange() throws CustomChangeException {
if (configured) {
return;
}
try {
for (String param : params) {
ObjectUtil.setProperty(customChange, param, paramValues.get(param));
}
customChange.setFileOpener(Scope.getCurrentScope().getResourceAccessor());
customChange.setUp();
configured = true;
} catch (Exception e) {
throw new CustomChangeException(e);
}
}
@Override
public SerializationType getSerializableFieldType(String field) {
switch (field) {
case "class":
return SerializationType.NAMED_FIELD;
case "param":
return SerializationType.NAMED_FIELD;
default:
throw new UnexpectedLiquibaseException("Unexpected CustomChangeWrapper field " + field);
}
}
@Override
public Object getSerializableFieldValue(String field) {
switch (field) {
case "class":
return getClassName();
case "param":
return this.paramValues;
default:
throw new UnexpectedLiquibaseException("Unexpected CustomChangeWrapper field " + field);
}
}
@Override
public Set getSerializableFields() {
return new HashSet<>(Arrays.asList("class", "param"));
}
@Override
public String getSerializedObjectNamespace() {
return STANDARD_CHANGELOG_NAMESPACE;
}
@Override
public void load(ParsedNode parsedNode, ResourceAccessor resourceAccessor) throws ParsedNodeException {
try {
String classNameValue = parsedNode.getChildValue(null, "class", String.class);
if (classNameValue == null) {
throw new ParsedNodeException("Custom change node has no 'class' attribute!");
}
setClass(classNameValue);
} catch (CustomChangeException e) {
throw new ParsedNodeException(e);
}
super.load(parsedNode, resourceAccessor);
}
@Override
public void customLoadLogic(ParsedNode parsedNode, ResourceAccessor resourceAccessor) throws ParsedNodeException {
ParsedNode paramsNode = parsedNode.getChild(null, "params");
if (paramsNode == null) {
paramsNode = parsedNode;
}
for (ParsedNode child : paramsNode.getChildren(null, "param")) {
Object value = child.getValue();
if (value == null) {
value = child.getChildValue(null, "value");
}
if (value != null) {
value = value.toString();
}
String paramName = child.getChildValue(null, "name", String.class);
if (paramName == null) {
throw new ParsedNodeException("Custom change param " + child + " does not have a 'name' attribute");
}
this.setParam(paramName, (String) value);
}
CustomChange customChange = null;
try {
Boolean osgiPlatform = Scope.getCurrentScope().get(Scope.Attr.osgiPlatform, Boolean.class);
if (Boolean.TRUE.equals(osgiPlatform)) {
customChange = (CustomChange)OsgiUtil.loadClass(className).getConstructor().newInstance();
} else {
customChange = (CustomChange) Class.forName(className, false, Scope.getCurrentScope().getClassLoader()).getConstructor().newInstance();
}
} catch (Exception e) {
throw new UnexpectedLiquibaseException(e);
}
for (ParsedNode node : parsedNode.getChildren()) {
Object value = node.getValue();
if ((value != null) && ObjectUtil.hasProperty(customChange, node.getName())) {
this.setParam(node.getName(), value.toString());
}
}
}
}