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Liquibase is a tool for managing and executing database changes.
package liquibase;
import liquibase.exception.UnexpectedLiquibaseException;
import liquibase.util.ObjectUtil;
import liquibase.util.SmartMap;
import liquibase.util.StringUtil;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.*;
/**
* Convenience class implementing ExtensibleObject. It is usually easiest to extend this class rather than implement all of ExtensibleObject yourself.
*/
public class AbstractExtensibleObject implements ExtensibleObject {
/**
* Additional non-standard attributes.
*/
private SmartMap attributes = new SmartMap();
/**
* Cache of fields on this object. Lazy loaded in {@link #getAttributeFields()}
*/
private static Map> attributeFieldCache = new HashMap<>();
public AbstractExtensibleObject() {
}
/**
* Creates a new object with the given attributes.
*/
public AbstractExtensibleObject(Map values) {
for (Map.Entry entry : values.entrySet()) {
this.set(entry.getKey(), entry.getValue());
}
}
@Override
public SortedSet getAttributes() {
SortedSet returnSet = new TreeSet<>(attributes.keySet());
for (String field : getAttributeFields().keySet()) {
if (has(field)) {
returnSet.add(field);
}
}
return Collections.unmodifiableSortedSet(returnSet);
}
@Override
public ObjectMetaData getObjectMetaData() {
ObjectMetaData metaData = new ObjectMetaData();
for (Field field : getAttributeFields().values()) {
ObjectMetaData.Attribute attribute = new ObjectMetaData.Attribute(field.getName());
attribute.type = field.getGenericType();
ExtensibleObjectAttribute annotation = field.getAnnotation(ExtensibleObjectAttribute.class);
if (annotation != null) {
attribute.description = annotation.description();
attribute.required = annotation.required();
}
metaData.attributes.add(attribute);
}
return metaData;
}
/**
* Return true if the given key is defined.
*/
@Override
public boolean has(String key) {
return get(key, Object.class) != null;
}
@Override
public T get(String attribute, Class type) {
return get(attribute, null, type);
}
@Override
public T get(String attribute, T defaultValue) {
Class type = (Class) Object.class;
if (defaultValue != null) {
type = (Class) defaultValue.getClass();
}
return get(attribute, defaultValue, type);
}
private Map getAttributeFields() {
Map fields = attributeFieldCache.get(this.getClass());
if (fields == null) {
fields = new HashMap<>();
for (Field field : this.getClass().getFields()) {
int modifiers = field.getModifiers();
if (Modifier.isPublic(modifiers) && !field.isSynthetic() && !Modifier.isFinal(modifiers) && !Modifier.isStatic(modifiers)) {
fields.put(field.getName(), field);
}
}
attributeFieldCache.put(this.getClass(), fields);
}
return fields;
}
protected T get(String attribute, T defaultValue, Class type) {
Object value;
if (attribute.contains(".")) {
List path = getValuePath(attribute, type);
value = path.get(path.size() - 1);
} else {
value = getFieldValue(attribute, type);
}
if (value == null) {
return defaultValue;
} else {
return (T) value;
}
}
@Override
public List getValuePath(String attributes, Class lastType) {
List path = new ArrayList();
String baseField;
String remainingAttribute = null;
int separatorIndex = attributes.indexOf('.');
if (separatorIndex < 0) {
baseField = attributes;
} else {
baseField = attributes.substring(0, separatorIndex);
remainingAttribute = attributes.substring(separatorIndex + 1);
}
Object lastValue = this;
while (baseField != null) {
boolean isLastField = remainingAttribute == null;
Object newValue;
Class typeToGet = isLastField ? lastType : Object.class;
if (lastValue == null) {
newValue = null;
} else if (lastValue instanceof ExtensibleObject) {
newValue = ((ExtensibleObject) lastValue).get(baseField, typeToGet);
} else if (lastValue instanceof Collection) {
newValue = new ArrayList<>();
boolean foundNonNullValue = false;
for (Object object : (Collection) lastValue) {
if (object == null) {
((Collection) newValue).add(null);
} else if (object instanceof ExtensibleObject) {
((Collection) newValue).add(((ExtensibleObject) object).get(baseField, typeToGet));
foundNonNullValue = true;
} else {
throw new UnexpectedLiquibaseException("Cannot traverse field(s) " + baseField + " on a " + object.getClass().getName());
}
}
if (!foundNonNullValue) {
newValue = null;
}
} else {
throw new UnexpectedLiquibaseException("Cannot traverse field(s) " + baseField + " on a " + lastValue.getClass().getName());
}
if (newValue instanceof Collection) {
List flattenedCollection = new ArrayList();
for (Object obj : (Collection) newValue) {
if (obj instanceof Collection) {
flattenedCollection.addAll((Collection) obj);
} else {
flattenedCollection.add(obj);
}
}
newValue = flattenedCollection;
}
path.add(newValue);
lastValue = newValue;
if (remainingAttribute == null) {
baseField = null;
} else {
separatorIndex = remainingAttribute.indexOf('.');
if (separatorIndex < 0) {
baseField = remainingAttribute;
remainingAttribute = null;
} else {
baseField = remainingAttribute.substring(0, separatorIndex);
remainingAttribute = remainingAttribute.substring(separatorIndex + 1);
}
}
}
return path;
}
protected Object getFieldValue(String attribute, Class type) {
Object value;
Field field = getAttributeFields().get(attribute);
if (field == null) {
value = attributes.get(attribute, type);
} else {
try {
value = ObjectUtil.convert(field.get(this), type);
} catch (IllegalAccessException e) {
throw new UnexpectedLiquibaseException(e);
}
}
return value;
}
@Override
public ExtensibleObject set(String attribute, Object value) {
Field field = getAttributeFields().get(attribute);
if (field == null) {
attributes.set(attribute, value);
} else {
try {
field.set(this, ObjectUtil.convert(value, field.getType()));
} catch (Exception e) {
throw new UnexpectedLiquibaseException("Error setting " + getClass().getName() + "." + attribute, e);
}
}
return this;
}
@Override
public String describe() {
String name = getClass().getSimpleName();
return name + "{" + StringUtil.join(this, ", ", new StringUtil.DefaultFormatter()) + "}";
}
@Override
public String toString() {
return describe();
}
@Override
public int hashCode() {
return toString().hashCode();
}
/**
* Default implementation counts objects equal if their describe() methods return equal strings.
*/
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
return obj instanceof AbstractExtensibleObject && this.describe().equals(((AbstractExtensibleObject) obj).describe());
}
@Override
public Object clone() {
try {
AbstractExtensibleObject clone = (AbstractExtensibleObject) super.clone();
for (String attr : getAttributes()) {
Object value = this.get(attr, Object.class);
if (value instanceof Collection) {
try {
Collection valueClone = (Collection) value.getClass().getConstructor().newInstance();
valueClone.addAll(((Collection) value));
value = valueClone;
} catch (Exception e) {
//keep original object
}
} else if (value instanceof Map) {
try {
Map valueClone = (Map) value.getClass().getConstructor().newInstance();
valueClone.putAll((Map) value);
value = valueClone;
} catch (Exception e) {
//keep original object
}
} else if (value instanceof AbstractExtensibleObject) {
value = ((AbstractExtensibleObject) value).clone();
}
clone.set(attr, value);
}
return clone;
} catch (CloneNotSupportedException e) {
throw new UnexpectedLiquibaseException(e);
}
}
}