Another Zell Depot patch:
- refactoring query construction; - modified collection lookup to first look up the matching primary keys, then check the cache for hits then look up the remainder from the database; - other small renamery and cleanup.
This commit is contained in:
Michael Bayne
@@ -0,0 +1,219 @@
|
||||
//
|
||||
// $Id$
|
||||
//
|
||||
// samskivert library - useful routines for java programs
|
||||
// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
|
||||
//
|
||||
// This library is free software; you can redistribute it and/or modify it
|
||||
// under the terms of the GNU Lesser General Public License as published
|
||||
// by the Free Software Foundation; either version 2.1 of the License, or
|
||||
// (at your option) any later version.
|
||||
//
|
||||
// This library is distributed in the hope that it will be useful,
|
||||
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
// Lesser General Public License for more details.
|
||||
//
|
||||
// You should have received a copy of the GNU Lesser General Public
|
||||
// License along with this library; if not, write to the Free Software
|
||||
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||||
package com.samskivert.jdbc.depot;
|
||||
|
||||
import java.sql.Connection;
|
||||
import java.sql.PreparedStatement;
|
||||
import java.sql.ResultSet;
|
||||
import java.sql.SQLException;
|
||||
import java.util.ArrayList;
|
||||
import java.util.HashMap;
|
||||
import java.util.List;
|
||||
import java.util.Map;
|
||||
|
||||
import net.sf.ehcache.Cache;
|
||||
import net.sf.ehcache.Element;
|
||||
|
||||
import com.samskivert.io.PersistenceException;
|
||||
import com.samskivert.jdbc.JDBCUtil;
|
||||
import com.samskivert.jdbc.depot.operator.Logic.*;
|
||||
import com.samskivert.jdbc.depot.clause.FieldOverride;
|
||||
import com.samskivert.jdbc.depot.clause.Join;
|
||||
import com.samskivert.jdbc.depot.clause.QueryClause;
|
||||
import com.samskivert.jdbc.depot.clause.Where;
|
||||
import com.samskivert.jdbc.depot.expression.SQLExpression;
|
||||
import com.samskivert.util.ArrayUtil;
|
||||
|
||||
/**
|
||||
* This class implements the functionality required by {@link DepotRepository#findAll): fetch
|
||||
* a collection of persistent objects using one of two included strategies.
|
||||
*/
|
||||
public abstract class FindAllQuery<T extends PersistentRecord>
|
||||
implements Query<List<T>>
|
||||
{
|
||||
/**
|
||||
* The two-pass collection query implementation. {@see DepotRepository#findAll} for details.
|
||||
*/
|
||||
public static class WithCache<T extends PersistentRecord> extends FindAllQuery<T>
|
||||
{
|
||||
public WithCache (PersistenceContext ctx, Class<T> type, QueryClause[] clauses)
|
||||
throws PersistenceException
|
||||
{
|
||||
super(ctx, type);
|
||||
_types = SQLQueryBuilder.getDepotTypes(ctx, type, clauses);
|
||||
_clauses = clauses;
|
||||
}
|
||||
|
||||
public List<T> invoke (Connection conn) throws SQLException {
|
||||
SQLQueryBuilder<T> keyFieldQuery = new SQLQueryBuilder<T>(
|
||||
_ctx, _types, _marsh.getPrimaryKeyColumns(), _clauses);
|
||||
PreparedStatement stmt = keyFieldQuery.prepare(conn);
|
||||
|
||||
Map<Key<T>, T> entities = new HashMap<Key<T>, T>();
|
||||
List<Key<T>> allKeys = new ArrayList<Key<T>>();
|
||||
List<Key<T>> fetchKeys = new ArrayList<Key<T>>();
|
||||
try {
|
||||
ResultSet rs = stmt.executeQuery();
|
||||
while (rs.next()) {
|
||||
Key<T> key = _marsh.makePrimaryKey(rs);
|
||||
allKeys.add(key);
|
||||
|
||||
// TODO: All this cache fiddling needs to move to PersistenceContext?
|
||||
Cache cache = _ctx.getCache(key.getCacheId());
|
||||
Element hit = cache.get(key.getCacheKey());
|
||||
if (hit != null) {
|
||||
@SuppressWarnings("unchecked") T value = (T) hit.getValue();
|
||||
if (value != null) {
|
||||
@SuppressWarnings("unchecked") T newValue = (T) value.clone();
|
||||
entities.put(key, newValue);
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
fetchKeys.add(key);
|
||||
}
|
||||
|
||||
} finally {
|
||||
JDBCUtil.close(stmt);
|
||||
}
|
||||
|
||||
if (fetchKeys.size() > 0) {
|
||||
int jj = 0;
|
||||
QueryClause[] newClauses = new QueryClause[_clauses.length + 1];
|
||||
// a select subset of query clauses are preserved for the entity query
|
||||
for (int ii = 0; ii < _clauses.length; ii ++) {
|
||||
if (_clauses[ii] instanceof Join || _clauses[ii] instanceof FieldOverride) {
|
||||
newClauses[jj ++] = _clauses[ii];
|
||||
}
|
||||
}
|
||||
SQLExpression[] keyArray = fetchKeys.toArray(new SQLExpression[0]);
|
||||
|
||||
// add our special key-matching where clause
|
||||
newClauses[jj ++] = new Where(new Or(keyArray));
|
||||
newClauses = ArrayUtil.splice(newClauses, jj);
|
||||
|
||||
// build the new query
|
||||
SQLQueryBuilder<T> entityQuery = new SQLQueryBuilder<T>(
|
||||
_ctx, _types, _marsh.getFieldNames(), newClauses);
|
||||
|
||||
// and execute it
|
||||
stmt = entityQuery.prepare(conn);
|
||||
|
||||
try {
|
||||
ResultSet rs = stmt.executeQuery();
|
||||
for (Key<T> key : fetchKeys) {
|
||||
if (!rs.next()) {
|
||||
throw new SQLException("Expecting more rows in result set.");
|
||||
}
|
||||
entities.put(key, _marsh.createObject(rs));
|
||||
}
|
||||
|
||||
} finally {
|
||||
JDBCUtil.close(stmt);
|
||||
}
|
||||
}
|
||||
|
||||
List<T> result = new ArrayList<T>();
|
||||
for (Key<T> key : allKeys) {
|
||||
result.add(entities.get(key));
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
protected DepotTypes<T> _types;
|
||||
protected QueryClause[] _clauses;
|
||||
}
|
||||
|
||||
/**
|
||||
* The single-pass collection query implementation. {@see DepotRepository#findAll} for details.
|
||||
*/
|
||||
public static class Explicitly<T extends PersistentRecord> extends FindAllQuery<T>
|
||||
{
|
||||
public Explicitly (PersistenceContext ctx, Class<T> type, QueryClause[] clauses)
|
||||
throws PersistenceException
|
||||
{
|
||||
super(ctx, type);
|
||||
DepotTypes<List<T>> types = SQLQueryBuilder.getDepotTypes(ctx, type, clauses);
|
||||
_builder = new SQLQueryBuilder<List<T>>(ctx, types, _marsh.getFieldNames(), clauses);
|
||||
}
|
||||
|
||||
public List<T> invoke (Connection conn) throws SQLException {
|
||||
PreparedStatement stmt = _builder.prepare(conn);
|
||||
|
||||
List<T> result = new ArrayList<T>();
|
||||
try {
|
||||
ResultSet rs = stmt.executeQuery();
|
||||
while (rs.next()) {
|
||||
result.add(_marsh.createObject(rs));
|
||||
}
|
||||
|
||||
} finally {
|
||||
JDBCUtil.close(stmt);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
protected SQLQueryBuilder<List<T>> _builder;
|
||||
}
|
||||
|
||||
public FindAllQuery (PersistenceContext ctx, Class<T> type)
|
||||
throws PersistenceException
|
||||
{
|
||||
_ctx = ctx;
|
||||
_marsh = _ctx.getMarshaller(type);
|
||||
}
|
||||
|
||||
// from Query
|
||||
public CacheKey getCacheKey ()
|
||||
{
|
||||
return null;
|
||||
}
|
||||
|
||||
// from Query
|
||||
public void updateCache (PersistenceContext ctx, List<T> result) {
|
||||
if (_marsh.hasPrimaryKey()) {
|
||||
for (T bit : result) {
|
||||
ctx.cacheStore(_marsh.getPrimaryKey(bit), bit.clone());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// from Query
|
||||
public List<T> transformCacheHit (CacheKey key, List<T> bits)
|
||||
{
|
||||
if (bits == null) {
|
||||
return bits;
|
||||
}
|
||||
|
||||
List<T> result = new ArrayList<T>();
|
||||
for (T bit : bits) {
|
||||
if (bit != null) {
|
||||
@SuppressWarnings("unchecked") T cbit = (T) bit.clone();
|
||||
result.add(cbit);
|
||||
} else {
|
||||
result.add(null);
|
||||
}
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
protected PersistenceContext _ctx;
|
||||
protected DepotMarshaller<T> _marsh;
|
||||
}
|
||||
Reference in New Issue
Block a user