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A Scala ORM and DSL for talking with Databases using minimum verbosity and maximum type safety
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/*******************************************************************************
* Copyright 2010 Maxime Lévesque
*
* Licensed 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.squeryl.dsl
import ast._
import internal.{InnerJoinedQueryable, OuterJoinedQueryable}
import java.sql.ResultSet
import org.squeryl.internals._
import org.squeryl.{View, Queryable, Session, Query}
import collection.mutable.ArrayBuffer
import org.squeryl.logging._
import java.io.Closeable
abstract class AbstractQuery[R](
val isRoot:Boolean,
private [squeryl] val unions: List[(String, Query[R])]
) extends Query[R] {
private [squeryl] var selectDistinct = false
private [squeryl] var isForUpdate = false
private [squeryl] var page: Option[(Int,Int)] = None
private [squeryl] var unionIsForUpdate = false
private [squeryl] var unionPage: Option[(Int, Int)] = None
private var __root: Option[Query[R]] = None
val resultSetMapper = new ResultSetMapper
val name = "query"
private def isUnionQuery = ! unions.isEmpty
override private [squeryl] def root = __root
def give(rsm: ResultSetMapper, rs: ResultSet): R = {
rsm.pushYieldedValues(rs)
val r = invokeYield(rsm, rs)
r
}
/**
* Builds the AST tree of the this Query, *some state mutation of the AST nodes occurs
* during AST construction, for example, the parent child relationship is set by this method,
* unique IDs of node that needs them for example.
*
* After this call, the query (and it's AST) becomes immutable by virtue of the unaccessibility
* of it's public methods
*/
val definitionSite: Option[StackTraceElement] =
if(!isRoot) None
else Some(_deduceDefinitionSite)
private def _deduceDefinitionSite: StackTraceElement = {
val st = Thread.currentThread.getStackTrace
var i = 1
while(i < st.length) {
val e = st(i)
val cn = e.getClassName
if((cn.startsWith("org.squeryl.") && (!cn.startsWith("org.squeryl.tests."))) || cn.startsWith("scala."))
i = i + 1
else
return e
}
new StackTraceElement("unknown", "unknown", "unknown", -1)
}
protected def copyUnions(u: List[(String, Query[R])]) =
u map (t => (t._1, t._2.copy(false, Nil)))
protected def buildAst(qy: QueryYield[R], subQueryables: SubQueryable[_]*) = {
val subQueries = new ArrayBuffer[QueryableExpressionNode]
val views = new ArrayBuffer[ViewExpressionNode[_]]
if(qy.joinExpressions != Nil) {
val sqIterator = subQueryables.iterator
val joinExprsIterator = qy.joinExpressions.iterator
sqIterator.next // get rid of the first one
while(sqIterator.hasNext) {
val nthQueryable = sqIterator.next
val nthJoinExpr = joinExprsIterator.next
nthQueryable.node.joinExpression = Some(nthJoinExpr())
}
}
for(sq <- subQueryables)
if(! sq.isQuery)
views.append(sq.node.asInstanceOf[ViewExpressionNode[_]])
for(sq <- subQueryables)
if(sq.isQuery) {
val z = sq.node.asInstanceOf[QueryExpressionNode[_]]
if(! z.isUseableAsSubquery)
org.squeryl.internals.Utils.throwError("Sub query returns a primitive type or a Tuple of primitive type, and therefore is not useable as a subquery in a from or join clause, see \nhttp://squeryl.org/limitations.html")
subQueries.append(z)
}
val qen = new QueryExpressionNode[R](this, qy, subQueries, views)
val (sl,d) = qy.invokeYieldForAst(qen, resultSetMapper)
qen.setOutExpressionNodesAndSample(sl, d)
// sl.filter(_.isInstanceOf[ExportedSelectElement]).
// map(_.asInstanceOf[ExportedSelectElement]).
// foreach(_.buildReferencePath)
qen
}
def ast: QueryExpressionNode[R]
def copy(asRoot:Boolean, newUnions: List[(String, Query[R])]) = {
val c = createCopy(asRoot, newUnions)
c.selectDistinct = selectDistinct
c.page = page
if (! isRoot) {
c.__root = __root
} else {
c.__root = Some(this)
}
c
}
def createCopy(asRoot:Boolean, newUnions: List[(String, Query[R])]): AbstractQuery[R]
def dumpAst = ast.dumpAst
def statement: String = _genStatement(true)
private def _genStatement(forDisplay: Boolean) = {
val sw = new StatementWriter(forDisplay, Session.currentSession.databaseAdapter)
ast.write(sw)
sw.statement
}
def distinct = {
if (isUnionQuery) {
Utils.throwError("distinct is not supported on union queries")
}
val c = copy(true, Nil)
c.selectDistinct = true;
c
}
def page(offset: Int, pageLength: Int): Query[R] = {
val c = copy(true, Nil)
val page = Some((offset, pageLength))
if (c.isUnionQuery)
c.unionPage = page
else
c.page = page
c
}
def forUpdate = {
val c = copy(true, Nil)
if (c.isUnionQuery)
c.unionIsForUpdate = true
else
c.isForUpdate = true;
c
}
private def _dbAdapter = Session.currentSession.databaseAdapter
def iterator = new Iterator[R] with Closeable {
val sw = new StatementWriter(false, _dbAdapter)
ast.write(sw)
val s = Session.currentSession
val beforeQueryExecute = System.currentTimeMillis
val (rs, stmt) = _dbAdapter.executeQuery(s, sw)
lazy val statEx = new StatementInvocationEvent(definitionSite.get, beforeQueryExecute, System.currentTimeMillis, -1, sw.statement)
if(s.statisticsListener != None)
s.statisticsListener.get.queryExecuted(statEx)
s._addStatement(stmt) // if the iteration doesn't get completed, we must hang on to the statement to clean it up at session end.
s._addResultSet(rs) // same for the result set
var _nextCalled = false;
var _hasNext = false;
var rowCount = 0
def close {
stmt.close
rs.close
}
def _next = {
_hasNext = rs.next
if(!_hasNext) {// close it since we've completed the iteration
Utils.close(rs)
stmt.close
if(s.statisticsListener != None) {
s.statisticsListener.get.resultSetIterationEnded(statEx.uuid, System.currentTimeMillis, rowCount, true)
}
}
rowCount = rowCount + 1
_nextCalled = true
}
def hasNext = {
if(!_nextCalled)
_next
_hasNext
}
def next: R = {
if(!_nextCalled)
_next
if(!_hasNext)
throw new NoSuchElementException("next called with no rows available")
_nextCalled = false
if(s.isLoggingEnabled)
s.log(ResultSetUtils.dumpRow(rs))
give(resultSetMapper, rs)
}
}
override def toString = dumpAst + "\n" + _genStatement(true)
protected def createSubQueryable[U](q: Queryable[U]): SubQueryable[U] =
if(q.isInstanceOf[View[_]]) {
val v = q.asInstanceOf[View[U]]
val vxn = v.viewExpressionNode
vxn.sample =
v.posoMetaData.createSample(FieldReferenceLinker.createCallBack(vxn))
new SubQueryable(v, vxn.sample, vxn.resultSetMapper, false, vxn)
}
else if(q.isInstanceOf[OptionalQueryable[_]]) {
val oqr = q.asInstanceOf[OptionalQueryable[U]]
val sq = createSubQueryable[U](oqr.queryable)
sq.node.inhibited = oqr.inhibited
val oqCopy = new OptionalQueryable(sq.queryable)
oqCopy.inhibited = oqr.inhibited
new SubQueryable(oqCopy.asInstanceOf[Queryable[U]], Some(sq.sample).asInstanceOf[U], sq.resultSetMapper, sq.isQuery, sq.node)
}
else if(q.isInstanceOf[OuterJoinedQueryable[_]]) {
val ojq = q.asInstanceOf[OuterJoinedQueryable[U]]
val sq = createSubQueryable[U](ojq.queryable)
sq.node.joinKind = Some((ojq.leftRightOrFull, "outer"))
sq.node.inhibited = ojq.inhibited
new SubQueryable(sq.queryable, Some(sq.sample).asInstanceOf[U], sq.resultSetMapper, sq.isQuery, sq.node)
}
else if(q.isInstanceOf[InnerJoinedQueryable[_]]) {
val ijq = q.asInstanceOf[InnerJoinedQueryable[U]]
val sq = createSubQueryable[U](ijq.queryable)
sq.node.joinKind = Some((ijq.leftRightOrFull, "inner"))
new SubQueryable(sq.queryable, sq.sample, sq.resultSetMapper, sq.isQuery, sq.node)
}
else if(q.isInstanceOf[DelegateQuery[_]]) {
createSubQueryable(q.asInstanceOf[DelegateQuery[U]].q)
}
else {
val qr = q.asInstanceOf[AbstractQuery[U]]
val copy = qr.copy(false, Nil)
new SubQueryable(copy, copy.ast.sample.asInstanceOf[U], copy.resultSetMapper, true, copy.ast)
}
protected class SubQueryable[U]
(val queryable: Queryable[U],
val sample: U,
val resultSetMapper: ResultSetMapper,
val isQuery:Boolean,
val node: QueryableExpressionNode) {
def give(rs: ResultSet): U =
if(node.joinKind != None) {
if(node.isOuterJoined) {
val isNoneInOuterJoin =
(!isQuery) && resultSetMapper.isNoneInOuterJoin(rs)
if(isNoneInOuterJoin)
None.asInstanceOf[U]
else
Some(queryable.give(resultSetMapper, rs)).asInstanceOf[U]
}
else
queryable.give(resultSetMapper, rs)
}
else if((node.isRightJoined) && resultSetMapper.isNoneInOuterJoin(rs))
sample
else
queryable.give(resultSetMapper, rs)
}
private def createUnion(kind: String, q: Query[R]): Query[R] =
copy(true, List((kind, q)))
def union(q: Query[R]): Query[R] = createUnion("Union", q)
def unionAll(q: Query[R]): Query[R] = createUnion("Union All", q)
def intersect(q: Query[R]): Query[R] = createUnion("Intersect", q)
def intersectAll(q: Query[R]): Query[R] = createUnion("Intersect All", q)
def except(q: Query[R]): Query[R] = createUnion("Except", q)
def exceptAll(q: Query[R]): Query[R] = createUnion("Except All", q)
}