/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.jdbc.meta.strats;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import org.apache.openjpa.enhance.FieldManager;
import org.apache.openjpa.enhance.PersistenceCapable;
import org.apache.openjpa.jdbc.kernel.JDBCFetchConfiguration;
import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.meta.FieldMapping;
import org.apache.openjpa.jdbc.meta.FieldStrategy;
import org.apache.openjpa.jdbc.meta.RelationId;
import org.apache.openjpa.jdbc.meta.ValueMapping;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.schema.ForeignKey;
import org.apache.openjpa.jdbc.sql.Joins;
import org.apache.openjpa.jdbc.sql.Result;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.jdbc.sql.SelectExecutor;
import org.apache.openjpa.jdbc.sql.Union;
import org.apache.openjpa.kernel.OpenJPAStateManager;
import org.apache.openjpa.kernel.StateManagerImpl;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.meta.JavaTypes;
import org.apache.openjpa.util.ChangeTracker;
import org.apache.openjpa.util.Id;
import org.apache.openjpa.util.OpenJPAId;
import org.apache.openjpa.util.Proxy;
import org.apache.openjpa.util.DelayedProxy;
/**
* Base class for strategies that are stored as a collection, even if
* their field value is something else. Handles data loading and basic query
* functionality. Subclasses must implement abstract methods and
* insert/update/delete behavior as well as overriding
* {@link FieldStrategy#toDataStoreValue}, {@link FieldStrategy#join}, and
* {@link FieldStrategy#joinRelation} if necessary.
*
* @author Abe White
*/
public abstract class StoreCollectionFieldStrategy
extends ContainerFieldStrategy {
/**
* Return the foreign key used to join to the owning field for the given
* element mapping from {@link #getIndependentElementMappings} (or null).
*/
protected abstract ForeignKey getJoinForeignKey(ClassMapping elem);
/**
* Implement this method to select the elements of this field for the
* given element mapping from {@link #getIndependentElementMappings}
* (or null). Elements of the result will be loaded with
* {@link #loadElement}.
*/
protected abstract void selectElement(Select sel, ClassMapping elem,
JDBCStore store, JDBCFetchConfiguration fetch, int eagerMode,
Joins joins);
/**
* Load an element of the collection. The given state manager might be
* null if the load is for a projection or for processing eager parallel
* results.
*/
protected abstract Object loadElement(OpenJPAStateManager sm,
JDBCStore store, JDBCFetchConfiguration fetch, Result res, Joins joins)
throws SQLException;
/**
* Join this value's table to the table for the given element mapping
* from {@link #getIndependentElementMappings} (or null).
*
* @see FieldMapping#joinRelation
*/
protected abstract Joins joinElementRelation(Joins joins,
ClassMapping elem);
/**
* Join to the owning field table for the given element mapping from
* {@link #getIndependentElementMappings} (or null).
*/
protected abstract Joins join(Joins joins, ClassMapping elem);
/**
* Return a large result set proxy for this field.
*/
protected abstract Proxy newLRSProxy();
/**
* Convert the field value to a collection. Handles collections and
* arrays by default.
*/
protected Collection toCollection(Object val) {
if (field.getTypeCode() == JavaTypes.COLLECTION)
return (Collection) val;
return JavaTypes.toList(val, field.getElement().getType(), false);
}
/**
* Add an item to the data structure representing a field value.
* By default, assumes the structure is a collection.
*/
protected void add(JDBCStore store, Object coll, Object obj) {
((Collection<Object>) coll).add(obj);
}
/**
* Returns the first independent element mapping, or null.
*/
private ClassMapping getDefaultElementMapping(boolean traverse) {
ClassMapping[] elems = getIndependentElementMappings(traverse);
return (elems.length == 0) ? null : elems[0];
}
public int supportsSelect(Select sel, int type, OpenJPAStateManager sm,
JDBCStore store, JDBCFetchConfiguration fetch) {
if (field.isLRS())
return 0;
if (type == Select.EAGER_PARALLEL)
return Math.max(1, getIndependentElementMappings(true).length);
if (type != Select.EAGER_INNER && type != Select.EAGER_OUTER)
return 0;
if (getIndependentElementMappings(true).length > 1)
return 0;
return (type == Select.EAGER_INNER || store.getDBDictionary().
canOuterJoin(sel.getJoinSyntax(), getJoinForeignKey
(getDefaultElementMapping(false)))) ? 1 : 0;
}
public void selectEagerParallel(SelectExecutor sel,
final OpenJPAStateManager sm, final JDBCStore store,
final JDBCFetchConfiguration fetch, final int eagerMode) {
if (!(sel instanceof Union))
selectEager((Select) sel, getDefaultElementMapping(true), sm,
store, fetch, eagerMode, true, false);
else {
final ClassMapping[] elems = getIndependentElementMappings(true);
Union union = (Union) sel;
if (fetch.getSubclassFetchMode(field.getElementMapping().
getTypeMapping()) != fetch.EAGER_JOIN)
union.abortUnion();
union.select(new Union.Selector() {
public void select(Select sel, int idx) {
selectEager(sel, elems[idx], sm, store, fetch, eagerMode,
true, false);
}
});
}
}
public void selectEagerJoin(Select sel, OpenJPAStateManager sm,
JDBCStore store, JDBCFetchConfiguration fetch, int eagerMode) {
// we limit further eager fetches to joins, because after this point
// the select has been modified such that parallel clones may produce
// invalid sql
boolean outer = field.getNullValue() != FieldMapping.NULL_EXCEPTION;
// force inner join for inner join fetch
if (fetch.hasFetchInnerJoin(field.getFullName(false)))
outer = false;
selectEager(sel, getDefaultElementMapping(true), sm, store, fetch,
JDBCFetchConfiguration.EAGER_JOIN, false,
outer);
}
public boolean isEagerSelectToMany() {
return true;
}
/**
* Select our data eagerly.
*/
private void selectEager(Select sel, ClassMapping elem,
OpenJPAStateManager sm, JDBCStore store, JDBCFetchConfiguration fetch,
int eagerMode, boolean selectOid, boolean outer) {
// force distinct if there was a to-many join to avoid dups, but
// if this is a parallel select don't make distinct based on the
// eager joins alone if the original wasn't distinct
if (eagerMode == JDBCFetchConfiguration.EAGER_PARALLEL) {
if (sel.hasJoin(true))
sel.setDistinct(true);
else if (!sel.isDistinct())
sel.setDistinct(false); // set explicitly so remembered
}
// set a variable name that does not conflict with any in the query;
// using a variable guarantees that the selected data will use different
// aliases and joins than any existing WHERE conditions on this field
// that might otherwise limit the elements of the field that match
if (selectOid)
sel.orderByPrimaryKey(field.getDefiningMapping(), true, true);
Joins joins = sel.newJoins().setVariable("*");
joins = join(joins, elem);
// order, ref cols
if (field.getOrderColumn() != null || field.getOrders().length > 0
|| !selectOid) {
if (outer)
joins = sel.outer(joins);
if (!selectOid) {
Column[] refs = getJoinForeignKey(elem).getColumns();
sel.orderBy(refs, true, joins, true);
}
field.orderLocal(sel, elem, joins);
}
// select data
joins = joinElementRelation(joins, elem);
if (outer)
joins = sel.outer(joins);
field.orderRelation(sel, elem, joins);
selectElement(sel, elem, store, fetch, eagerMode, joins);
}
public Object loadEagerParallel(OpenJPAStateManager sm, JDBCStore store,
JDBCFetchConfiguration fetch, Object res)
throws SQLException {
// process batched results if we haven't already
Map rels;
if (res instanceof Result)
rels = processEagerParallelResult(sm, store, fetch, (Result) res);
else
rels = (Map) res;
// look up the collection for this oid, and store in instance
Object coll = rels.remove(sm.getObjectId());
if (field.getTypeCode() == JavaTypes.ARRAY)
sm.storeObject(field.getIndex(), JavaTypes.toArray
((Collection) coll, field.getElement().getType()));
else {
if (coll == null)
coll = sm.newProxy(field.getIndex());
sm.storeObject(field.getIndex(), coll);
}
return rels;
}
/**
* Process the given batched result.
*/
private Map processEagerParallelResult(OpenJPAStateManager sm,
JDBCStore store, JDBCFetchConfiguration fetch, Result res)
throws SQLException {
// do same joins as for load
//### cheat: we know typical result joins only care about the relation
//### path; thus we can ignore different mappings
ClassMapping elem = getDefaultElementMapping(true);
Joins dataJoins = res.newJoins().setVariable("*");
dataJoins = join(dataJoins, elem);
dataJoins = joinElementRelation(dataJoins, elem);
Joins orderJoins = null;
if (field.getOrderColumn() != null) {
orderJoins = res.newJoins().setVariable("*");
orderJoins = join(orderJoins, elem);
}
Map rels = new HashMap();
ClassMapping ownerMapping = field.getDefiningMapping();
Object nextOid, oid = null;
Object coll = null;
int seq = 0;
while (res.next()) {
// extract the owner id value
nextOid = getNextObjectId(ownerMapping, store, res, oid);
if (nextOid != oid) {
// if the old coll was an ordered tracking proxy, set
// its seq value to the last order val we read
if (seq != 0 && coll instanceof Proxy)
((Proxy) coll).getChangeTracker().setNextSequence(seq);
// start a new collection
oid = nextOid;
seq = 0;
if (field.getTypeCode() == JavaTypes.ARRAY)
coll = new ArrayList();
else
coll = sm.newProxy(field.getIndex());
rels.put(oid, coll);
}
if (field.getOrderColumn() != null)
seq = res.getInt(field.getOrderColumn(), orderJoins) + 1;
// for inverse relation field
setMappedBy(oid.equals(sm.getObjectId()) ?
sm.getPersistenceCapable() : oid, res);
Object val = loadElement(null, store, fetch, res, dataJoins);
add(store, coll, val);
}
res.close();
return rels;
}
private void setMappedBy(Object oid, Result res) {
// for inverse toOne relation field
FieldMapping mappedByFieldMapping = field.getMappedByMapping();
if (mappedByFieldMapping != null) {
ValueMapping val = mappedByFieldMapping.getValueMapping();
ClassMetaData decMeta = val.getTypeMetaData();
// this inverse field does not have corresponding classMapping
// its value may be a collection/map etc.
if (decMeta == null)
return;
res.setMappedByFieldMapping(mappedByFieldMapping);
res.setMappedByValue(oid);
}
}
private void setMappedBy(Object oid, OpenJPAStateManager sm, Object coll,
Result res) {
// for inverseEager field
FieldMapping mappedByFieldMapping = field.getMappedByMapping();
PersistenceCapable mappedByValue = null;
if (mappedByFieldMapping != null) {
ValueMapping val = mappedByFieldMapping.getValueMapping();
ClassMetaData decMeta = val.getTypeMetaData();
// this inverse field does not have corresponding classMapping
// its value may be a collection/map etc.
if (decMeta == null)
return;
StateManagerImpl owner = ((StateManagerImpl)sm).getObjectIdOwner();
if (oid.equals(owner.getObjectId())) {
mappedByValue = owner.getPersistenceCapable();
res.setMappedByFieldMapping(mappedByFieldMapping);
res.setMappedByValue(mappedByValue);
} else if (coll instanceof Collection &&
((Collection) coll).size() > 0) {
// Customer (1) <--> Orders(n)
// coll contains the values of the toMany field (Orders)
// get the StateManager of this toMany value
// and find the value of the inverse mappedBy field (Customer)
// for this toMacdny field
PersistenceCapable pc = (PersistenceCapable)
((Collection) coll).iterator().next();
OpenJPAStateManager sm1 = (OpenJPAStateManager) pc.
pcGetStateManager();
ClassMapping clm = ((ClassMapping) sm1.getMetaData());
FieldMapping fm = (FieldMapping) clm.getField(
mappedByFieldMapping.getName());
if (fm == mappedByFieldMapping)
res.setMappedByValue(sm1.fetchObject(fm.getIndex()));
} else {
res.setMappedByValue(null);
}
}
}
/**
* Extract the oid value from the given result. If the next oid is the
* same as the given one, returns the given JVM instance.
*/
private Object getNextObjectId(ClassMapping owner, JDBCStore store,
Result res, Object oid)
throws SQLException {
// if this is a datastore id class we can avoid creating a new oid
// object for the common case
if (oid != null && owner.getIdentityType() == ClassMapping.ID_DATASTORE
&& owner.isPrimaryKeyObjectId(true)) {
long nid = res.getLong(owner.getPrimaryKeyColumns()[0]);
long id = ((Id) oid).getId();
return (nid == id) ? oid : store.newDataStoreId(nid, owner, true);
}
Object noid = owner.getObjectId(store, res, null, true, null);
if (noid == null)
return null;
return (noid.equals(oid)) ? oid : noid;
}
public void loadEagerJoin(OpenJPAStateManager sm, JDBCStore store,
JDBCFetchConfiguration fetch, Result res)
throws SQLException {
// initialize field value
Object coll;
if (field.getTypeCode() == JavaTypes.ARRAY)
coll = new ArrayList();
else
coll = sm.newProxy(field.getIndex());
Joins dataJoins = null;
Joins refJoins = res.newJoins().setVariable("*");
join(refJoins, false);
ClassMapping ownerMapping = field.getDefiningMapping();
Object ref = null;
int seq = 0;
int typeIdx = res.indexOf();
for (int i = 0; true; i++) {
// extract the owner id value
ref = getNextRef(ownerMapping, store, res, ref, refJoins);
if (ref == null) {
// if the old coll was an ordered tracking proxy, set
// its seq value to the last order val we read
if (seq != 0 && coll instanceof Proxy)
((Proxy) coll).getChangeTracker().setNextSequence(seq);
if (i != 0)
res.pushBack();
break;
}
// do same joins as for load
if (dataJoins == null) {
dataJoins = res.newJoins().setVariable("*");
dataJoins = join(dataJoins, false);
dataJoins = joinRelation(dataJoins, false, false);
}
if (field.getOrderColumn() != null)
seq = res.getInt(field.getOrderColumn(), refJoins) + 1;
res.setBaseMapping(null);
Object obj = loadElement(sm, store, fetch, res, dataJoins);
if (obj != null)
add(store, coll, obj);
if (!res.next() || res.indexOf() != typeIdx) {
res.pushBack();
break;
}
}
// load the collection into the object
if (field.getTypeCode() == JavaTypes.ARRAY)
sm.storeObject(field.getIndex(), JavaTypes.toArray
((Collection) coll, field.getElement().getType()));
else
sm.storeObject(field.getIndex(), coll);
}
/**
* Extract the reference column value(s) from the given result. If the
* extracted result is the same as the current one or the current
* one is null, returns the extracted result. Else returns null.
*/
private Object getNextRef(ClassMapping mapping, JDBCStore store,
Result res, Object ref, Joins refJoins)
throws SQLException {
Column[] cols = getJoinForeignKey(getDefaultElementMapping(false)).
getColumns();
Object val;
if (cols.length == 1) {
val = res.getObject(cols[0], null, refJoins);
if (val == null || (ref != null && !val.equals(ref)))
return null;
return val;
}
Object[] refs = (Object[]) ref;
if (refs == null)
refs = new Object[cols.length];
for (int i = 0; i < cols.length; i++) {
val = res.getObject(cols[i], null, refJoins);
if (val == null)
return null;
if (refs[i] != null && !val.equals(refs[i]))
return null;
refs[i] = val;
}
return refs;
}
public void load(final OpenJPAStateManager sm, final JDBCStore store,
final JDBCFetchConfiguration fetch)
throws SQLException {
Object coll = null;
final int fieldIndex = field.getIndex();
final boolean delayed = sm.isDelayed(fieldIndex);
if (!delayed && field.isDelayCapable()) {
coll = sm.newProxy(fieldIndex);
if (coll instanceof DelayedProxy) {
sm.storeObject(fieldIndex, coll);
sm.setDelayed(fieldIndex, true);
return;
}
}
if (field.isLRS()) {
Proxy pcoll = newLRSProxy();
// if this is ordered we need to know the next seq to use in case
// objects are added to the collection
if (field.getOrderColumn() != null) {
// we don't allow ordering table per class one-many's, so
// we know we don't need a union
Select sel = store.getSQLFactory().newSelect();
sel.setAggregate(true);
StringBuilder sql = new StringBuilder();
sql.append("MAX(").
append(sel.getColumnAlias(field.getOrderColumn())).
append(")");
sel.select(sql.toString(), field);
ClassMapping rel = getDefaultElementMapping(false);
sel.whereForeignKey(getJoinForeignKey(rel),
sm.getObjectId(), field.getDefiningMapping(), store);
Result res = sel.execute(store, fetch);
try {
res.next();
pcoll.getChangeTracker().setNextSequence
(res.getInt(field) + 1);
} finally {
res.close();
}
}
sm.storeObjectField(fieldIndex, pcoll);
return;
}
// select data for this sm
final ClassMapping[] elems = getIndependentElementMappings(true);
final Joins[] resJoins = new Joins[Math.max(1, elems.length)];
Union union = store.getSQLFactory().newUnion
(Math.max(1, elems.length));
union.select(new Union.Selector() {
public void select(Select sel, int idx) {
ClassMapping elem = (elems.length == 0) ? null : elems[idx];
resJoins[idx] = selectAll(sel, elem, sm, store, fetch,
JDBCFetchConfiguration.EAGER_PARALLEL);
}
});
// create proxy
ChangeTracker ct = null;
if (delayed) {
if (sm.isDetached() || sm.getOwner() == null) {
sm.getPersistenceCapable().pcProvideField(fieldIndex);
coll =
((FieldManager)sm.getPersistenceCapable().pcGetStateManager()).fetchObjectField(fieldIndex);
} else {
coll = sm.fetchObjectField(fieldIndex);
}
if (coll instanceof Proxy)
ct = ((Proxy) coll).getChangeTracker();
} else {
if (field.getTypeCode() == JavaTypes.ARRAY)
coll = new ArrayList();
else {
if (coll == null) {
coll = sm.newProxy(fieldIndex);
}
if (coll instanceof Proxy)
ct = ((Proxy) coll).getChangeTracker();
}
}
// load values
Result res = union.execute(store, fetch);
try {
int seq = -1;
while (res.next()) {
if (ct != null && field.getOrderColumn() != null)
seq = res.getInt(field.getOrderColumn());
setMappedBy(sm.getObjectId(), sm, coll, res);
add(store, coll, loadElement(sm, store, fetch, res,
resJoins[res.indexOf()]));
}
if (ct != null && field.getOrderColumn() != null)
ct.setNextSequence(seq + 1);
} finally {
res.close();
}
// if not a delayed collection, set into sm
if (!delayed) {
if (field.getTypeCode() == JavaTypes.ARRAY)
sm.storeObject(fieldIndex, JavaTypes.toArray
((Collection) coll, field.getElement().getType()));
else
sm.storeObject(fieldIndex, coll);
}
}
/**
* Select data for loading, starting in field table.
*/
protected Joins selectAll(Select sel, ClassMapping elem,
OpenJPAStateManager sm, JDBCStore store, JDBCFetchConfiguration fetch,
int eagerMode) {
ForeignKey fk = getJoinForeignKey(elem);
Object oid = getObjectIdForJoin(fk, sm);
sel.whereForeignKey(fk, oid, field.getDefiningMapping(), store);
// order first, then select so that if the projection introduces
// additional ordering, it will be after our required ordering
field.orderLocal(sel, elem, null);
Joins joins = joinElementRelation(sel.newJoins(), elem);
field.orderRelation(sel, elem, joins);
selectElement(sel, elem, store, fetch, eagerMode, joins);
return joins;
}
public Object loadProjection(JDBCStore store, JDBCFetchConfiguration fetch,
Result res, Joins joins)
throws SQLException {
return loadElement(null, store, fetch, res, joins);
}
public ForeignKey getJoinForeignKey() {
return getJoinForeignKey(getDefaultElementMapping(false));
}
/**
* Gets the identity value of the given instance that is suitable to join to the given foreign key.
* The special case of the foreign key being a relation identifier will encode the value.
*/
Object getObjectIdForJoin(ForeignKey fk, OpenJPAStateManager sm) {
Object oid = sm.getObjectId();
if (!RelationStrategies.isRelationId(fk)) {
return oid;
}
FieldMapping owningField = field.getMappedByMapping();
if (owningField != null && owningField.getHandler() instanceof RelationId) {
return ((RelationId)owningField.getHandler()).toRelationDataStoreValue(sm, null);
}
if (oid instanceof OpenJPAId) {
return ((OpenJPAId)oid).getIdObject();
}
return oid;
}
}