//$Id: Example.java,v 1.1.2.9 2003/11/12 15:27:44 oneovthafew Exp $
package net.sf.hibernate.expression;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.engine.SessionFactoryImplementor;
import net.sf.hibernate.engine.TypedValue;
import net.sf.hibernate.metadata.ClassMetadata;
import net.sf.hibernate.type.AbstractComponentType;
import net.sf.hibernate.type.Type;
import net.sf.hibernate.util.StringHelper;
/**
* Support for query by example.
*
* List results = session.createCriteria(Parent.class)
* .add( Example.create(parent).ignoreCase() )
* .createCriteria("child")
* .add( Example.create( parent.getChild() ) )
* .list();
*
* "Examples" may be mixed and matched with "Expressions" in the same Criteria.
* @see net.sf.hibernate.Criteria
* @author Gavin King
*/
public class Example extends AbstractCriterion {
private final Object entity;
private final Set excludedProperties = new HashSet();
private PropertySelector selector;
private boolean isLikeEnabled;
private boolean isIgnoreCaseEnabled;
private MatchMode matchMode;
/**
* A strategy for choosing property values for inclusion in the query
* criteria
*/
public static interface PropertySelector {
public boolean include(Object propertyValue, String propertyName, Type type);
}
private static final PropertySelector NOT_NULL = new NotNullPropertySelector();
private static final PropertySelector ALL = new AllPropertySelector();
private static final PropertySelector NOT_NULL_OR_ZERO = new NotNullOrZeroPropertySelector();
static final class AllPropertySelector implements PropertySelector {
public boolean include(Object object, String propertyName, Type type) {
return true;
}
}
static final class NotNullPropertySelector implements PropertySelector {
public boolean include(Object object, String propertyName, Type type) {
return object!=null;
}
}
static final class NotNullOrZeroPropertySelector implements PropertySelector {
public boolean include(Object object, String propertyName, Type type) {
return object!=null && (
!(object instanceof Number) || ( (Number) object ).longValue()!=0
);
}
}
/**
* Set the property selector
*/
public Example setPropertySelector(PropertySelector selector) {
this.selector = selector;
return this;
}
/**
* Exclude zero-valued properties
*/
public Example excludeZeroes() {
setPropertySelector(NOT_NULL_OR_ZERO);
return this;
}
/**
* Don't exclude null or zero-valued properties
*/
public Example excludeNone() {
setPropertySelector(ALL);
return this;
}
/**
* Use the "like" operator for all string-valued properties
*/
public Example enableLike(MatchMode matchMode) {
isLikeEnabled = true;
this.matchMode = matchMode;
return this;
}
/**
* Use the "like" operator for all string-valued properties
*/
public Example enableLike() {
return enableLike(MatchMode.EXACT);
}
/**
* Ignore case for all string-valued properties
*/
public Example ignoreCase() {
isIgnoreCaseEnabled = true;
return this;
}
/**
* Exclude a particular named property
*/
public Example excludeProperty(String name) {
excludedProperties.add(name);
return this;
}
/**
* Create a new instance, which includes all non-null properties
* by default
* @param entity
* @return a new instance of Example
*/
public static Example create(Object entity) {
if (entity==null) throw new NullPointerException("null example");
return new Example(entity, NOT_NULL);
}
protected Example(Object entity, PropertySelector selector) {
this.entity = entity;
this.selector = selector;
}
public String toString() {
return entity.toString();
}
private boolean isPropertyIncluded(Object value, String name, Type type) {
return !excludedProperties.contains(name) &&
!type.isAssociationType() &&
selector.include(value, name, type);
}
public String toSqlString(
SessionFactoryImplementor sessionFactory,
Class persistentClass,
String alias,
Map aliasClasses)
throws HibernateException {
StringBuffer buf = new StringBuffer().append(StringHelper.OPEN_PAREN);
ClassMetadata meta = sessionFactory.getClassMetadata(persistentClass);
String[] propertyNames = meta.getPropertyNames();
Type[] propertyTypes = meta.getPropertyTypes();
Object[] propertyValues = meta.getPropertyValues(entity);
for (int i=0; i Object propertyValue = propertyValues[i];
String propertyName = propertyNames[i];
boolean isPropertyIncluded = i!=meta.getVersionProperty() &&
isPropertyIncluded( propertyValue, propertyName, propertyTypes[i] );
if (isPropertyIncluded) {
if ( propertyTypes[i].isComponentType() ) {
appendComponentCondition(
propertyName,
propertyValue,
(AbstractComponentType) propertyTypes[i],
persistentClass,
alias,
aliasClasses,
sessionFactory,
buf
);
}
else {
appendPropertyCondition(
propertyName,
propertyValue,
persistentClass,
alias,
aliasClasses,
sessionFactory,
buf
);
}
}
}
if ( buf.length()==1 ) buf.append("1=1"); //yuck!
return buf.append(StringHelper.CLOSE_PAREN).toString();
}
private static final Object[] TYPED_VALUES = new TypedValue[0];
public TypedValue[] getTypedValues(
SessionFactoryImplementor sessionFactory,
Class persistentClass,
Map aliasClasses)
throws HibernateException {
ClassMetadata meta = sessionFactory.getClassMetadata(persistentClass);
String[] propertyNames = meta.getPropertyNames();
Type[] propertyTypes = meta.getPropertyTypes();
Object[] values = meta.getPropertyValues(entity);
List list = new ArrayList();
for (int i=0; i Object value = values[i];
Type type = propertyTypes[i];
String name = propertyNames[i];
boolean isPropertyIncluded = i!=meta.getVersionProperty() &&
isPropertyIncluded(value, name, type);
if (isPropertyIncluded) {
if ( propertyTypes[i].isComponentType() ) {
addComponentTypedValues(name, value, (AbstractComponentType) type, list);
}
else {
addPropertyTypedValue(value, type, list);
}
}
}
return (TypedValue[]) list.toArray(TYPED_VALUES);
}
protected void addPropertyTypedValue(Object value, Type type, List list) {
if ( value!=null ) {
if ( value instanceof String ) {
String string = (String) value;
if (isIgnoreCaseEnabled) string = string.toLowerCase();
if (isLikeEnabled) string = matchMode.toMatchString(string);
value = string;
}
list.add( new TypedValue(type, value) );
}
}
protected void addComponentTypedValues(String path, Object component, AbstractComponentType type, List list)
throws HibernateException {
if (component!=null) {
String[] propertyNames = type.getPropertyNames();
Type[] subtypes = type.getSubtypes();
Object[] values = type.getPropertyValues(component);
for (int i=0; i Object value = values[i];
Type subtype = subtypes[i];
String subpath = StringHelper.qualify( path, propertyNames[i] );
if ( isPropertyIncluded(value, subpath, subtype) ) {
addPropertyTypedValue(value, subtype, list);
}
}
}
}
protected void appendPropertyCondition(
String propertyName,
Object propertyValue,
Class persistentClass,
String alias,
Map aliasClasses,
SessionFactoryImplementor sessionFactory,
StringBuffer buf)
throws HibernateException {
if ( buf.length()>1 ) buf.append(" and ");
Criterion crit;
if ( propertyValue!=null ) {
boolean isString = propertyValue instanceof String;
crit = ( isLikeEnabled && isString ) ?
(Criterion) new LikeExpression( propertyName, propertyValue, isIgnoreCaseEnabled ) :
(Criterion) new EqExpression( propertyName, propertyValue, isIgnoreCaseEnabled && isString );
}
else {
crit = new NullExpression(propertyName);
}
buf.append( crit.toSqlString(sessionFactory, persistentClass, alias, aliasClasses) );
}
protected void appendComponentCondition(
String path,
Object component,
AbstractComponentType type,
Class persistentClass,
String alias,
Map aliasClasses,
SessionFactoryImplementor sessionFactory,
StringBuffer buf)
throws HibernateException {
if (component!=null) {
String[] propertyNames = type.getPropertyNames();
Object[] values = type.getPropertyValues(component);
Type[] subtypes = type.getSubtypes();
for (int i=0; i String subpath = StringHelper.qualify( path, propertyNames[i] );
Object value = values[i];
if ( isPropertyIncluded( value, subpath, subtypes[i] ) ) {
appendPropertyCondition(
subpath,
value,
persistentClass,
alias,
aliasClasses,
sessionFactory,
buf
);
}
}
}
}
}
