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org.apache.openjpa.jdbc.kernel.exps.GetMapValue Maven / Gradle / Ivy
/*
* 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.kernel.exps;
import java.sql.SQLException;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.meta.FieldMapping;
import org.apache.openjpa.jdbc.meta.JavaSQLTypes;
import org.apache.openjpa.jdbc.meta.strats.ContainerFieldStrategy;
import org.apache.openjpa.jdbc.meta.strats.LRSMapFieldStrategy;
import org.apache.openjpa.jdbc.meta.strats.RelationStrategies;
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.SQLBuffer;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.kernel.Filters;
import org.apache.openjpa.meta.ClassMetaData;
/**
* Returns the value of the given map's key.
*
* @author Marc Prud'hommeaux
*/
class GetMapValue
extends AbstractVal {
private final Val _map;
private final Val _key;
private final String _alias;
private ClassMetaData _meta = null;
private Class _cast = null;
/**
* Constructor. Provide the map and key to operate on.
*/
public GetMapValue(Val map, Val key, String alias) {
_map = map;
_key = key;
_alias = alias;
}
public ClassMetaData getMetaData() {
return _meta;
}
public void setMetaData(ClassMetaData meta) {
_meta = meta;
}
public boolean isVariable() {
return false;
}
public Class getType() {
if (_cast != null)
return _cast;
return _map.getType();
}
public void setImplicitType(Class type) {
_cast = type;
}
public ExpState initialize(Select sel, ExpContext ctx, int flags) {
ExpState mapState = _map.initialize(sel, ctx, 0);
ExpState keyState = _key.initialize(sel, ctx, 0);
return new GetMapValueExpState(sel.and(mapState.joins, keyState.joins),
mapState, keyState);
}
/**
* Expression state.
*/
private static class GetMapValueExpState
extends ExpState {
public final ExpState mapState;
public final ExpState keyState;
public GetMapValueExpState(Joins joins, ExpState mapState,
ExpState keyState) {
super(joins);
this.mapState = mapState;
this.keyState = keyState;
}
}
public Object toDataStoreValue(Select sel, ExpContext ctx, ExpState state,
Object val) {
GetMapValueExpState gstate = (GetMapValueExpState) state;
return _map.toDataStoreValue(sel, ctx, gstate.mapState, val);
}
public void select(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
sel.select(newSQLBuffer(sel, ctx, state).append(" AS ").append(_alias),
this);
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
GetMapValueExpState gstate = (GetMapValueExpState) state;
_map.selectColumns(sel, ctx, gstate.mapState, true);
_key.selectColumns(sel, ctx, gstate.keyState, true);
}
public void groupBy(Select sel, ExpContext ctx, ExpState state) {
sel.groupBy(newSQLBuffer(sel, ctx, state));
}
public void orderBy(Select sel, ExpContext ctx, ExpState state,
boolean asc) {
sel.orderBy(_alias, asc, false);
}
private SQLBuffer newSQLBuffer(Select sel, ExpContext ctx, ExpState state) {
calculateValue(sel, ctx, state, null, null);
SQLBuffer buf = new SQLBuffer(ctx.store.getDBDictionary());
appendTo(sel, ctx, state, buf, 0);
return buf;
}
public Object load(ExpContext ctx, ExpState state, Result res)
throws SQLException {
return Filters.convert(res.getObject(this,
JavaSQLTypes.JDBC_DEFAULT, null), getType());
}
public void calculateValue(Select sel, ExpContext ctx, ExpState state,
Val other, ExpState otherState) {
GetMapValueExpState gstate = (GetMapValueExpState) state;
_map.calculateValue(sel, ctx, gstate.mapState, null, null);
_key.calculateValue(sel, ctx, gstate.keyState, null, null);
}
public int length(Select sel, ExpContext ctx, ExpState state) {
return 1;
}
public void appendTo(Select sel, ExpContext ctx, ExpState state,
SQLBuffer sql, int index) {
if (!(_map instanceof PCPath))
throw new UnsupportedOperationException();
if (!(_key instanceof Const))
throw new UnsupportedOperationException();
GetMapValueExpState gstate = (GetMapValueExpState) state;
PCPath map = (PCPath) _map;
Object key = ((Const) _key).getValue(ctx, gstate.keyState);
FieldMapping field = map.getFieldMapping(gstate.mapState);
if (!(field.getStrategy() instanceof LRSMapFieldStrategy))
throw new UnsupportedOperationException();
LRSMapFieldStrategy strat = (LRSMapFieldStrategy) field.getStrategy();
ClassMapping[] clss = strat.getIndependentValueMappings(true);
if (clss != null && clss.length > 1)
throw RelationStrategies.unjoinable(field);
ClassMapping cls = (clss == null || clss.length == 0) ? null : clss[0];
ForeignKey fk = strat.getJoinForeignKey(cls);
// manually create a subselect for the Map's value
sql.append("(SELECT ");
Column[] values = field.getElementMapping().getColumns();
for (int i = 0; i < values.length; i++) {
if (i > 0)
sql.append(", ");
sql.append(values[i].getTable()).append(".").append(values[i]);
}
sql.append(" FROM ").append(values[0].getTable());
sql.append(" WHERE ");
// add in the joins
ContainerFieldStrategy.appendUnaliasedJoin(sql, sel, null,
ctx.store.getDBDictionary(), field, fk);
sql.append(" AND ");
key = strat.toKeyDataStoreValue(key, ctx.store);
Column[] cols = strat.getKeyColumns(cls);
Object[] vals = (cols.length == 1) ? null : (Object[]) key;
for (int i = 0; i < cols.length; i++) {
sql.append(cols[i].getTable()).append(".").append(cols[i]);
if (vals == null)
sql.append((key == null) ? " IS " : " = ").
appendValue(key, cols[i]);
else
sql.append((vals[i] == null) ? " IS " : " = ").
appendValue(vals[i], cols[i]);
}
sql.append(")");
}
}
