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/*
* 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.JavaSQLTypes;
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.kernel.exps.ExpressionVisitor;
import org.apache.openjpa.meta.ClassMetaData;
/**
* Aggregate listener that evaluates to a value.
*
* @author Abe White
*/
class Aggregate
extends AbstractVal {
private final JDBCAggregateListener _listener;
private final Val _arg;
private final ClassMapping _candidate;
private ClassMetaData _meta = null;
private Class _cast = null;
/**
* Constructor.
*/
public Aggregate(JDBCAggregateListener listener, Val arg,
ClassMapping candidate) {
_listener = listener;
_arg = arg;
_candidate = candidate;
}
public ClassMetaData getMetaData() {
return _meta;
}
public void setMetaData(ClassMetaData meta) {
_meta = meta;
}
public boolean isAggregate() {
return true;
}
public Class getType() {
if (_cast != null)
return _cast;
return _listener.getType(getArgTypes());
}
private Class[] getArgTypes() {
if (_arg == null)
return null;
if (_arg instanceof Args)
return ((Args) _arg).getTypes();
return new Class[]{ _arg.getType() };
}
public void setImplicitType(Class type) {
_cast = type;
}
public ExpState initialize(Select sel, ExpContext ctx, int flags) {
if (_arg == null)
return ExpState.NULL;
// note that we tell targets and args to extensions that are sql
// paths to go ahead and join to their related object (if any),
// because we assume that, unlike most operations, if a relation
// field like a 1-1 is given as the target of an extension, then
// the extension probably acts on some field or column in the
// related object, not the 1-1 field itself
return _arg.initialize(sel, ctx, JOIN_REL);
}
public void select(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
sel.select(newSQLBuffer(sel, ctx, state), this);
sel.setAggregate(true);
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
if (_arg != null)
_arg.selectColumns(sel, ctx, state, 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(newSQLBuffer(sel, ctx, state), asc, false,
getSelectAs());
}
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) {
if (_arg != null)
_arg.calculateValue(sel, ctx, state, 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) {
_listener.appendTo(sql, getArgs(sel, ctx, state), _candidate,
ctx.store);
sel.append(sql, state.joins);
}
private FilterValue[] getArgs(Select sel, ExpContext ctx, ExpState state) {
if (_arg == null)
return null;
if (_arg instanceof Args)
return ((Args) _arg).newFilterValues(sel, ctx, state);
return new FilterValue[]{
new FilterValueImpl(sel, ctx, state, _arg)
};
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
if (_arg != null)
_arg.acceptVisit(visitor);
visitor.exit(this);
}
}
