Java tutorial
/* * Hibernate, Relational Persistence for Idiomatic Java * * License: GNU Lesser General Public License (LGPL), version 2.1 or later. * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>. */ package org.hibernate; import java.util.List; import org.hibernate.criterion.CriteriaSpecification; import org.hibernate.criterion.Criterion; import org.hibernate.criterion.Order; import org.hibernate.criterion.Projection; import org.hibernate.sql.JoinType; import org.hibernate.transform.ResultTransformer; /** * <tt>Criteria</tt> is a simplified API for retrieving entities * by composing <tt>Criterion</tt> objects. This is a very * convenient approach for functionality like "search" screens * where there is a variable number of conditions to be placed * upon the result set.<br> * <br> * The <tt>Session</tt> is a factory for <tt>Criteria</tt>. * <tt>Criterion</tt> instances are usually obtained via * the factory methods on <tt>Restrictions</tt>. eg. * <pre> * List cats = session.createCriteria(Cat.class) * .add( Restrictions.like("name", "Iz%") ) * .add( Restrictions.gt( "weight", new Float(minWeight) ) ) * .addOrder( Order.asc("age") ) * .list(); * </pre> * You may navigate associations using <tt>createAlias()</tt> or * <tt>createCriteria()</tt>. * <pre> * List cats = session.createCriteria(Cat.class) * .createCriteria("kittens") * .add( Restrictions.like("name", "Iz%") ) * .list(); * </pre> * <pre> * List cats = session.createCriteria(Cat.class) * .createAlias("kittens", "kit") * .add( Restrictions.like("kit.name", "Iz%") ) * .list(); * </pre> * You may specify projection and aggregation using <tt>Projection</tt> * instances obtained via the factory methods on <tt>Projections</tt>. * <pre> * List cats = session.createCriteria(Cat.class) * .setProjection( Projections.projectionList() * .add( Projections.rowCount() ) * .add( Projections.avg("weight") ) * .add( Projections.max("weight") ) * .add( Projections.min("weight") ) * .add( Projections.groupProperty("color") ) * ) * .addOrder( Order.asc("color") ) * .list(); * </pre> * * @see Session#createCriteria(java.lang.Class) * @see org.hibernate.criterion.Restrictions * @see org.hibernate.criterion.Projections * @see org.hibernate.criterion.Order * @see org.hibernate.criterion.Criterion * @see org.hibernate.criterion.Projection * @see org.hibernate.criterion.DetachedCriteria a disconnected version of this API * @author Gavin King */ public interface Criteria extends CriteriaSpecification { /** * Get the alias of the entity encapsulated by this criteria instance. * * @return The alias for the encapsulated entity. */ public String getAlias(); /** * Used to specify that the query results will be a projection (scalar in * nature). Implicitly specifies the {@link #PROJECTION} result transformer. * <p/> * The individual components contained within the given * {@link Projection projection} determines the overall "shape" of the * query result. * * @param projection The projection representing the overall "shape" of the * query results. * @return this (for method chaining) */ public Criteria setProjection(Projection projection); /** * Add a {@link Criterion restriction} to constrain the results to be * retrieved. * * @param criterion The {@link Criterion criterion} object representing the * restriction to be applied. * @return this (for method chaining) */ public Criteria add(Criterion criterion); /** * Add an {@link Order ordering} to the result set. * * @param order The {@link Order order} object representing an ordering * to be applied to the results. * @return this (for method chaining) */ public Criteria addOrder(Order order); /** * Specify an association fetching strategy for an association or a * collection of values. * * @param associationPath a dot separated property path * @param mode The fetch mode for the referenced association * * @return this (for method chaining) * * @throws HibernateException Indicates a problem applying the given fetch mode */ public Criteria setFetchMode(String associationPath, FetchMode mode) throws HibernateException; /** * Set the lock mode of the current entity. * * @param lockMode The lock mode to be applied * * @return this (for method chaining) */ public Criteria setLockMode(LockMode lockMode); /** * Set the lock mode of the aliased entity. * * @param alias The previously assigned alias representing the entity to * which the given lock mode should apply. * @param lockMode The lock mode to be applied * * @return this (for method chaining) */ public Criteria setLockMode(String alias, LockMode lockMode); /** * Join an association, assigning an alias to the joined association. * <p/> * Functionally equivalent to {@link #createAlias(String, String, JoinType )} using * {@link JoinType#INNER_JOIN} for the joinType. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * * @return this (for method chaining) * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createAlias(String associationPath, String alias) throws HibernateException; /** * Join an association using the specified join-type, assigning an alias * to the joined association. * <p/> * The joinType is expected to be one of {@link JoinType#INNER_JOIN} (the default), * {@link JoinType#FULL_JOIN}, or {@link JoinType#LEFT_OUTER_JOIN}. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * * @return this (for method chaining) * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createAlias(String associationPath, String alias, JoinType joinType) throws HibernateException; /** * Join an association using the specified join-type, assigning an alias * to the joined association. * <p/> * The joinType is expected to be one of {@link #INNER_JOIN} (the default), * {@link #FULL_JOIN}, or {@link #LEFT_JOIN}. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * * @return this (for method chaining) * * @throws HibernateException Indicates a problem creating the sub criteria * @deprecated use {@link #createAlias(String, String, org.hibernate.sql.JoinType)} */ @Deprecated public Criteria createAlias(String associationPath, String alias, int joinType) throws HibernateException; /** * Join an association using the specified join-type, assigning an alias * to the joined association. * <p/> * The joinType is expected to be one of {@link JoinType#INNER_JOIN} (the default), * {@link JoinType#FULL_JOIN}, or {@link JoinType#LEFT_OUTER_JOIN}. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * @param withClause The criteria to be added to the join condition (<tt>ON</tt> clause) * * @return this (for method chaining) * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createAlias(String associationPath, String alias, JoinType joinType, Criterion withClause) throws HibernateException; /** * Join an association using the specified join-type, assigning an alias * to the joined association. * <p/> * The joinType is expected to be one of {@link #INNER_JOIN} (the default), * {@link #FULL_JOIN}, or {@link #LEFT_JOIN}. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * @param withClause The criteria to be added to the join condition (<tt>ON</tt> clause) * * @return this (for method chaining) * * @throws HibernateException Indicates a problem creating the sub criteria * @deprecated use {@link #createAlias(String, String, JoinType, Criterion)} */ @Deprecated public Criteria createAlias(String associationPath, String alias, int joinType, Criterion withClause) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity. * <p/> * Functionally equivalent to {@link #createCriteria(String, org.hibernate.sql.JoinType)} using * {@link JoinType#INNER_JOIN} for the joinType. * * @param associationPath A dot-separated property path * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createCriteria(String associationPath) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, using the * specified join type. * * @param associationPath A dot-separated property path * @param joinType The type of join to use. * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createCriteria(String associationPath, JoinType joinType) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, using the * specified join type. * * @param associationPath A dot-separated property path * @param joinType The type of join to use. * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria * @deprecated use {@link #createAlias(String, String, org.hibernate.sql.JoinType)} */ @Deprecated public Criteria createCriteria(String associationPath, int joinType) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, * assigning the given alias. * <p/> * Functionally equivalent to {@link #createCriteria(String, String, org.hibernate.sql.JoinType)} using * {@link JoinType#INNER_JOIN} for the joinType. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createCriteria(String associationPath, String alias) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, * assigning the given alias and using the specified join type. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createCriteria(String associationPath, String alias, JoinType joinType) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, * assigning the given alias and using the specified join type. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria * @deprecated use {@link #createCriteria(String, org.hibernate.sql.JoinType)} */ @Deprecated public Criteria createCriteria(String associationPath, String alias, int joinType) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, * assigning the given alias and using the specified join type. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * @param withClause The criteria to be added to the join condition (<tt>ON</tt> clause) * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria */ public Criteria createCriteria(String associationPath, String alias, JoinType joinType, Criterion withClause) throws HibernateException; /** * Create a new <tt>Criteria</tt>, "rooted" at the associated entity, * assigning the given alias and using the specified join type. * * @param associationPath A dot-separated property path * @param alias The alias to assign to the joined association (for later reference). * @param joinType The type of join to use. * @param withClause The criteria to be added to the join condition (<tt>ON</tt> clause) * * @return the created "sub criteria" * * @throws HibernateException Indicates a problem creating the sub criteria * @deprecated use {@link #createCriteria(String, String, org.hibernate.sql.JoinType, org.hibernate.criterion.Criterion)} */ @Deprecated public Criteria createCriteria(String associationPath, String alias, int joinType, Criterion withClause) throws HibernateException; /** * Set a strategy for handling the query results. This determines the * "shape" of the query result. * * @param resultTransformer The transformer to apply * @return this (for method chaining) * * @see #ROOT_ENTITY * @see #DISTINCT_ROOT_ENTITY * @see #ALIAS_TO_ENTITY_MAP * @see #PROJECTION */ public Criteria setResultTransformer(ResultTransformer resultTransformer); /** * Set a limit upon the number of objects to be retrieved. * * @param maxResults the maximum number of results * @return this (for method chaining) */ public Criteria setMaxResults(int maxResults); /** * Set the first result to be retrieved. * * @param firstResult the first result to retrieve, numbered from <tt>0</tt> * @return this (for method chaining) */ public Criteria setFirstResult(int firstResult); /** * Was the read-only/modifiable mode explicitly initialized? * * @return true, the read-only/modifiable mode was explicitly initialized; false, otherwise. * * @see Criteria#setReadOnly(boolean) */ public boolean isReadOnlyInitialized(); /** * Should entities and proxies loaded by this Criteria be put in read-only mode? If the * read-only/modifiable setting was not initialized, then the default * read-only/modifiable setting for the persistence context is returned instead. * @see Criteria#setReadOnly(boolean) * @see org.hibernate.engine.spi.PersistenceContext#isDefaultReadOnly() * * The read-only/modifiable setting has no impact on entities/proxies returned by the * Criteria that existed in the session before the Criteria was executed. * * @return true, entities and proxies loaded by the criteria will be put in read-only mode * false, entities and proxies loaded by the criteria will be put in modifiable mode * @throws IllegalStateException if <code>isReadOnlyInitialized()</code> returns <code>false</code> * and this Criteria is not associated with a session. * @see Criteria#isReadOnlyInitialized() */ public boolean isReadOnly(); /** * Set the read-only/modifiable mode for entities and proxies * loaded by this Criteria. This setting overrides the default setting * for the persistence context. * @see org.hibernate.engine.spi.PersistenceContext#isDefaultReadOnly() * * To set the default read-only/modifiable setting used for * entities and proxies that are loaded into the session: * @see org.hibernate.engine.spi.PersistenceContext#setDefaultReadOnly(boolean) * @see org.hibernate.Session#setDefaultReadOnly(boolean) * * Read-only entities are not dirty-checked and snapshots of persistent * state are not maintained. Read-only entities can be modified, but * changes are not persisted. * * When a proxy is initialized, the loaded entity will have the same * read-only/modifiable setting as the uninitialized * proxy has, regardless of the session's current setting. * * The read-only/modifiable setting has no impact on entities/proxies * returned by the criteria that existed in the session before the criteria was executed. * * @param readOnly true, entities and proxies loaded by the criteria will be put in read-only mode * false, entities and proxies loaded by the criteria will be put in modifiable mode * @return {@code this}, for method chaining */ public Criteria setReadOnly(boolean readOnly); /** * Set a fetch size for the underlying JDBC query. * * @param fetchSize the fetch size * @return this (for method chaining) * * @see java.sql.Statement#setFetchSize */ public Criteria setFetchSize(int fetchSize); /** * Set a timeout for the underlying JDBC query. * * @param timeout The timeout value to apply. * @return this (for method chaining) * * @see java.sql.Statement#setQueryTimeout */ public Criteria setTimeout(int timeout); /** * Enable caching of this query result, provided query caching is enabled * for the underlying session factory. * * @param cacheable Should the result be considered cacheable; default is * to not cache (false). * @return this (for method chaining) */ public Criteria setCacheable(boolean cacheable); /** * Set the name of the cache region to use for query result caching. * * @param cacheRegion the name of a query cache region, or <tt>null</tt> * for the default query cache * @return this (for method chaining) * * @see #setCacheable */ public Criteria setCacheRegion(String cacheRegion); /** * Add a comment to the generated SQL. * * @param comment a human-readable string * @return this (for method chaining) */ public Criteria setComment(String comment); /** * Add a DB query hint to the SQL. These differ from JPA's {@link javax.persistence.QueryHint}, which is specific * to the JPA implementation and ignores DB vendor-specific hints. Instead, these are intended solely for the * vendor-specific hints, such as Oracle's optimizers. Multiple query hints are supported; the Dialect will * determine concatenation and placement. * * @param hint The database specific query hint to add. * @return this (for method chaining) */ public Criteria addQueryHint(String hint); /** * Override the flush mode for this particular query. * * @param flushMode The flush mode to use. * @return this (for method chaining) */ public Criteria setFlushMode(FlushMode flushMode); /** * Override the cache mode for this particular query. * * @param cacheMode The cache mode to use. * @return this (for method chaining) */ public Criteria setCacheMode(CacheMode cacheMode); /** * Get the results. * * @return The list of matched query results. * * @throws HibernateException Indicates a problem either translating the criteria to SQL, * exeucting the SQL or processing the SQL results. */ public List list() throws HibernateException; /** * Get the results as an instance of {@link ScrollableResults}. * * @return The {@link ScrollableResults} representing the matched * query results. * * @throws HibernateException Indicates a problem either translating the criteria to SQL, * exeucting the SQL or processing the SQL results. */ public ScrollableResults scroll() throws HibernateException; /** * Get the results as an instance of {@link ScrollableResults} based on the * given scroll mode. * * @param scrollMode Indicates the type of underlying database cursor to * request. * * @return The {@link ScrollableResults} representing the matched * query results. * * @throws HibernateException Indicates a problem either translating the criteria to SQL, * exeucting the SQL or processing the SQL results. */ public ScrollableResults scroll(ScrollMode scrollMode) throws HibernateException; /** * Convenience method to return a single instance that matches * the query, or null if the query returns no results. * * @return the single result or <tt>null</tt> * @throws HibernateException if there is more than one matching result */ public Object uniqueResult() throws HibernateException; }