/*
* 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 java.util.Map;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.meta.JavaSQLTypes;
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.kernel.exps.ExpressionVisitor;
import org.apache.openjpa.meta.ClassMetaData;
/**
* Filter listener that evaluates to a value.
*
* @author Abe White
*/
class Extension
extends AbstractVal
implements Val, Exp {
private final JDBCFilterListener _listener;
private final Val _target;
private final Val _arg;
private final ClassMapping _candidate;
private ClassMetaData _meta = null;
private Class _cast = null;
/**
* Constructor.
*/
public Extension(JDBCFilterListener listener, Val target,
Val arg, ClassMapping candidate) {
_listener = listener;
_target = target;
_arg = arg;
_candidate = candidate;
}
public ClassMetaData getMetaData() {
return _meta;
}
public void setMetaData(ClassMetaData meta) {
_meta = meta;
}
public boolean isVariable() {
return false;
}
public boolean isAggregate() {
return false;
}
public Class getType() {
if (_cast != null)
return _cast;
Class targetClass = (_target == null) ? null : _target.getType();
return _listener.getType(targetClass, 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) {
// 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
ExpState targetState = null;
ExpState argState = null;
if (_target != null)
targetState = _target.initialize(sel, ctx, JOIN_REL);
if (_arg != null)
argState = _arg.initialize(sel, ctx, JOIN_REL);
Joins j1 = (targetState == null) ? null : targetState.joins;
Joins j2 = (argState == null) ? null : argState.joins;
return new ExtensionExpState(sel.and(j1, j2), targetState,
argState);
}
/**
* Expression state.
*/
private static class ExtensionExpState
extends ExpState {
public final ExpState targetState;
public final ExpState argState;
public ExtensionExpState(Joins joins, ExpState targetState,
ExpState argState) {
super(joins);
this.targetState = targetState;
this.argState = argState;
}
}
public void select(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
sel.select(newSQLBuffer(sel, ctx, state), this);
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
ExtensionExpState estate = (ExtensionExpState) state;
if (_target != null)
_target.selectColumns(sel, ctx, estate.targetState, true);
if (_arg != null)
_arg.selectColumns(sel, ctx, estate.argState, 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) {
ExtensionExpState estate = (ExtensionExpState) state;
if (_target != null)
_target.calculateValue(sel, ctx, estate.targetState, null, null);
if (_arg != null)
_arg.calculateValue(sel, ctx, estate.argState, 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) {
ExtensionExpState estate = (ExtensionExpState) state;
FilterValue target = (_target == null) ? null
: new FilterValueImpl(sel, ctx, estate.targetState, _target);
_listener.appendTo(sql, target, getArgs(sel, ctx, estate.argState),
_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((Exp) this);
if (_target != null)
_target.acceptVisit(visitor);
if (_arg != null)
_arg.acceptVisit(visitor);
visitor.exit((Exp) this);
}
//////////////////////
// Exp implementation
//////////////////////
public ExpState initialize(Select sel, ExpContext ctx, Map contains) {
return initialize(sel, ctx, 0);
}
public void appendTo(Select sel, ExpContext ctx, ExpState state,
SQLBuffer sql) {
calculateValue(sel, ctx, state, null, null);
appendTo(sel, ctx, state, sql, 0);
sel.append(sql, state.joins);
}
}