/*
* ModeShape (http://www.modeshape.org)
*
* 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.modeshape.jcr.query.model;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.modeshape.common.annotation.Immutable;
import org.modeshape.common.i18n.I18n;
import org.modeshape.common.util.CheckArg;
import org.modeshape.common.util.HashCode;
import org.modeshape.common.util.ObjectUtil;
import org.modeshape.jcr.GraphI18n;
import org.modeshape.jcr.api.query.qom.QueryObjectModelConstants;
/**
* This object acts as a Set operator on multiple {@link QueryCommand queries}, such as performing UNION, INTERSECT, and EXCEPT
* operations.
* <p>
* The two {@link QueryCommand queries} are expected to have the same number and order of columns, and the corresponding columns
* types must be compatible.
* </p>
*/
@Immutable
public class SetQuery implements QueryCommand, org.modeshape.jcr.api.query.qom.SetQuery {
private static final long serialVersionUID = 1L;
public enum Operation implements Readable {
UNION("UNION"),
INTERSECT("INTERSECT"),
EXCEPT("EXCEPT");
private static final Map<String, Operation> OPERATIONS_BY_SYMBOL;
static {
Map<String, Operation> opsBySymbol = new HashMap<String, Operation>();
for (Operation op : Operation.values()) {
opsBySymbol.put(op.getSymbol(), op);
}
OPERATIONS_BY_SYMBOL = Collections.unmodifiableMap(opsBySymbol);
}
private final String symbol;
private Operation( String symbol ) {
this.symbol = symbol;
}
/**
* @return symbol
*/
public String getSymbol() {
return symbol;
}
/**
* {@inheritDoc}
*
* @see java.lang.Enum#toString()
*/
@Override
public String toString() {
return symbol;
}
public static Operation forSymbol( String symbol ) {
CheckArg.isNotNull(symbol, "symbol");
return OPERATIONS_BY_SYMBOL.get(symbol.toUpperCase());
}
@Override
public String getString() {
return getSymbol();
}
}
protected static boolean unionableColumns( List<? extends Column> left,
List<? extends Column> right ) {
// Check the column size first ...
if (left.size() != right.size()) return false;
// Same size, so check the columns ...
Iterator<? extends Column> leftIter = left.iterator();
Iterator<? extends Column> rightIter = right.iterator();
while (leftIter.hasNext() && rightIter.hasNext()) {
Column leftColumn = leftIter.next();
Column rightColumn = rightIter.next();
if (leftColumn == null || rightColumn == null) return false;
}
return leftIter.hasNext() == rightIter.hasNext();
}
private final List<? extends Ordering> orderings;
private final Limit limits;
private final QueryCommand left;
private final QueryCommand right;
private final Operation operation;
private final boolean all;
private final int hc;
private transient Column[] columnArray;
private transient Ordering[] orderingArray;
/**
* Create a set query involving the supplied left- and right-hand-side queries.
*
* @param left the left-hand-side query being combined
* @param operation the set operation
* @param right the right-hand-side query being combined
* @param all true if all of the results should be included
* @throws IllegalArgumentException if the left-hand-side query, right-hand-side query, or operation are null
*/
public SetQuery( QueryCommand left,
Operation operation,
QueryCommand right,
boolean all ) {
CheckArg.isNotNull(left, "left");
CheckArg.isNotNull(right, "right");
CheckArg.isNotNull(operation, "operation");
if (!unionableColumns(left.columns(), right.columns())) {
I18n msg = GraphI18n.leftAndRightQueriesInSetQueryMustHaveUnionableColumns;
throw new IllegalArgumentException(msg.text(left.columns(), right.columns()));
}
this.left = left;
this.right = right;
this.operation = operation;
this.all = all;
this.orderings = Collections.<Ordering>emptyList();
this.limits = Limit.NONE;
this.hc = HashCode.compute(this.left, this.right, this.operation);
}
/**
* Create a set query involving the supplied left- and right-hand-side queries.
*
* @param left the left-hand-side query being combined
* @param operation the set operation
* @param right the right-hand-side query being combined
* @param all true if all of the results should be included
* @param orderings the specification of the order of the result rows, or null if the results need not be ordered
* @param limit the limit for the result rows, or null if there are no limits
* @throws IllegalArgumentException if the left-hand-side query, right-hand-side query, or operation are null
*/
public SetQuery( QueryCommand left,
Operation operation,
QueryCommand right,
boolean all,
List<? extends Ordering> orderings,
Limit limit ) {
CheckArg.isNotNull(left, "left");
CheckArg.isNotNull(right, "right");
CheckArg.isNotNull(operation, "operation");
if (!unionableColumns(left.columns(), right.columns())) {
I18n msg = GraphI18n.leftAndRightQueriesInSetQueryMustHaveUnionableColumns;
throw new IllegalArgumentException(msg.text(left.columns(), right.columns()));
}
this.left = left;
this.right = right;
this.operation = operation;
this.all = all;
this.orderings = orderings != null ? orderings : Collections.<Ordering>emptyList();
this.limits = limit != null ? limit : Limit.NONE;
this.hc = HashCode.compute(this.left, this.right, this.operation);
}
@Override
public List<? extends Column> columns() {
return left.columns(); // equivalent to right columns
}
@Override
public Limit getLimits() {
return limits;
}
@Override
public List<? extends Ordering> orderings() {
return orderings;
}
@Override
public QueryCommand getLeft() {
return left;
}
@Override
public QueryCommand getRight() {
return right;
}
/**
* Get the set operation for this query.
*
* @return the operation; never null
*/
public final Operation operation() {
return operation;
}
@Override
public String getOperation() {
switch (operation()) {
case UNION:
return QueryObjectModelConstants.JCR_SET_TYPE_UNION;
case INTERSECT:
return QueryObjectModelConstants.JCR_SET_TYPE_INTERSECT;
case EXCEPT:
return QueryObjectModelConstants.JCR_SET_TYPE_EXCEPT;
}
assert false;
return null;
}
@Override
public final boolean isAll() {
return all;
}
@Override
public Ordering[] getOrderings() {
if (orderingArray == null) {
// this is idempotent ...
orderingArray = orderings.toArray(new Ordering[orderings.size()]);
}
return orderingArray;
}
@Override
public Column[] getColumns() {
if (columnArray == null) {
// this is idempotent ...
List<? extends Column> columns = columns();
columnArray = columns.toArray(new Column[columns.size()]);
}
return columnArray;
}
@Override
public String toString() {
return Visitors.readable(this);
}
@Override
public int hashCode() {
return hc;
}
@Override
public boolean equals( Object obj ) {
if (obj == this) return true;
if (obj instanceof SetQuery) {
SetQuery that = (SetQuery)obj;
if (this.hc != that.hc) return false;
if (this.operation != that.operation) return false;
if (!this.left.equals(that.left)) return false;
if (!this.right.equals(that.right)) return false;
if (!ObjectUtil.isEqualWithNulls(this.getLimits(), that.getLimits())) return false;
if (!ObjectUtil.isEqualWithNulls(this.orderings(), that.orderings())) return false;
return true;
}
return false;
}
@Override
public void accept( Visitor visitor ) {
visitor.visit(this);
}
@Override
public SetQuery withLimit( int rowLimit ) {
if (getLimits().getRowLimit() == rowLimit) return this; // nothing to change
return new SetQuery(left, operation, right, all, orderings(), getLimits().withRowLimit(rowLimit));
}
@Override
public SetQuery withOffset( int offset ) {
if (getLimits().getOffset() == offset) return this; // nothing to change
return new SetQuery(left, operation, right, all, orderings(), getLimits().withOffset(offset));
}
public SetQuery adding( Ordering... orderings ) {
List<Ordering> newOrderings = null;
if (this.orderings() != null) {
newOrderings = new ArrayList<Ordering>(orderings());
for (Ordering ordering : orderings) {
newOrderings.add(ordering);
}
} else {
newOrderings = Arrays.asList(orderings);
}
return new SetQuery(left, operation, right, all, newOrderings, getLimits());
}
}