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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.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.sql.Joins;
import org.apache.openjpa.jdbc.sql.SQLBuffer;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.kernel.exps.ExpressionVisitor;
import org.apache.openjpa.kernel.exps.Parameter;
/**
* Tests whether a value is IN a collection.
*
* @author Abe White
*/
class InExpression
implements Exp {
private final Val _val;
private final Const _const;
/**
* Constructor. Supply the value to test and the constant to obtain
* the parameters from.
*/
public InExpression(Val val, Const constant) {
_val = val;
_const = constant;
}
/**
* Constant collection.
*/
public Const getConstant() {
return _const;
}
/**
* Contained value.
*/
public Val getValue() {
return _val;
}
public ExpState initialize(Select sel, ExpContext ctx, Map contains) {
ExpState valueState = _val.initialize(sel, ctx, 0);
ExpState constantState = _const.initialize(sel, ctx, 0);
return new InExpState(valueState.joins, constantState, valueState);
}
/**
* Expression state.
*/
private static class InExpState
extends ExpState {
public final ExpState constantState;
public final ExpState valueState;
public InExpState(Joins joins, ExpState constantState,
ExpState valueState) {
super(joins);
this.constantState = constantState;
this.valueState = valueState;
}
}
public void appendTo(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf) {
InExpState istate = (InExpState) state;
if (_val instanceof Type)
_const.calculateValue(sel, ctx, istate.constantState, _val,
istate.valueState);
else
_const.calculateValue(sel, ctx, istate.constantState, null, null);
_val.calculateValue(sel, ctx, istate.valueState, null, null);
List list = null;
Collection coll = getCollection(ctx, istate.constantState);
if (coll != null) {
list = new ArrayList(coll.size());
for (Iterator itr = coll.iterator(); itr.hasNext();)
list.add(_val.toDataStoreValue(sel, ctx, istate.valueState,
itr.next()));
}
Column[] cols = null;
if (_val instanceof PCPath)
cols = ((PCPath) _val).getColumns(istate.valueState);
else if (_val instanceof GetObjectId)
cols = ((GetObjectId) _val).getColumns(istate.valueState);
if (list == null || list.isEmpty())
buf.append("1 <> 1");
else if (_val.length(sel, ctx, istate.valueState) == 1)
createInContains(sel, ctx, istate.valueState, buf, list, cols);
else
orContains(sel, ctx, istate.valueState, buf, list, cols);
sel.append(buf, state.joins);
}
/**
* Based on the inClauseLimit of the DBDictionary, create the needed IN
* clauses
*/
private void createInContains(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf, List list, Column[] cols) {
int inClauseLimit = ctx.store.getDBDictionary().inClauseLimit;
if (inClauseLimit <= 0 || list.size() <= inClauseLimit)
inContains(sel, ctx, state, buf, list, cols);
else {
buf.append("(");
for (int low = 0, high; low < list.size(); low = high) {
if (low > 0)
buf.append(" OR ");
high = java.lang.Math.min(low + inClauseLimit, list.size());
inContains(sel, ctx, state, buf, list.subList(low, high), cols);
}
buf.append(")");
}
}
/**
* Construct an IN clause with the value of the given collection.
*/
private void inContains(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf, Collection coll, Column[] cols) {
_val.appendTo(sel, ctx, state, buf, 0);
buf.append(" IN (");
Column col = (cols != null && cols.length == 1) ? cols[0] : null;
for (Iterator itr = coll.iterator(); itr.hasNext();) {
buf.appendValue(itr.next(), col, _const instanceof Parameter
? (Parameter)_const : null);
if (itr.hasNext())
buf.append(", ");
}
buf.append(")");
}
/**
* If the value to test is a compound key, we can't use IN,
* so create a clause like '(a = b AND c = d) OR (e = f AND g = h) ...'
*/
private void orContains(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf, Collection coll, Column[] cols) {
if (coll.size() > 1)
buf.append("(");
Object[] vals;
Column col;
for (Iterator itr = coll.iterator(); itr.hasNext();) {
vals = (Object[]) itr.next();
buf.append("(");
for (int i = 0; i < vals.length; i++) {
col = (cols != null && cols.length == vals.length)
? cols[i] : null;
if (i > 0)
buf.append(" AND ");
_val.appendTo(sel, ctx, state, buf, i);
if (vals[i] == null)
buf.append(" IS ");
else
buf.append(" = ");
buf.appendValue(vals[i], col);
}
buf.append(")");
if (itr.hasNext())
buf.append(" OR ");
}
if (coll.size() > 1)
buf.append(")");
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
InExpState istate = (InExpState) state;
_const.selectColumns(sel, ctx, istate.constantState, true);
_val.selectColumns(sel, ctx, istate.valueState, true);
}
/**
* Return the collection to test for containment with.
*/
protected Collection getCollection(ExpContext ctx, ExpState state) {
Object val = _const.getValue(ctx, state);
// wrap non-Collection parameters in a Collections so the query
// lanuage can permit varargs "in" clauses
if (!(val instanceof Collection))
val = Collections.singleton(val);
return (Collection) val;
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
_val.acceptVisit(visitor);
_const.acceptVisit(visitor);
visitor.exit(this);
}
}
