/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.orient.core.sql.functions.coll;
import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.command.traverse.OTraverseRecordProcess;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.exception.OCommandExecutionException;
import com.orientechnologies.orient.core.record.impl.ODocument;
import com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Returns a traversed element from the stack. Use it with SQL traverse only.
*
* @author Luca Garulli (l.garulli--at--orientechnologies.com)
*
*/
public class OSQLFunctionTraversedElement extends OSQLFunctionConfigurableAbstract {
public static final String NAME = "traversedElement";
public OSQLFunctionTraversedElement(final String name) {
super(name, 1, 2);
}
public boolean aggregateResults() {
return false;
}
@Override
public Object getResult() {
return null;
}
@Override
public boolean filterResult() {
return true;
}
public String getSyntax() {
return getName() + "(<beginIndex> [,<items>])";
}
public Object execute(Object iThis, final OIdentifiable iCurrentRecord, Object iCurrentResult, final Object[] iParams,
final OCommandContext iContext) {
return evaluate(iParams, iContext, null);
}
protected Object evaluate(final Object[] iParams, final OCommandContext iContext, final String iClassName) {
final int beginIndex = (Integer) iParams[0];
final int items = iParams.length > 1 ? (Integer) iParams[1] : 1;
final ArrayDeque stack = (ArrayDeque) iContext.getVariable("stack");
if (stack == null)
throw new OCommandExecutionException("Cannot invoke " + getName() + "() against non traverse command");
final List<OIdentifiable> result = items > 1 ? new ArrayList<OIdentifiable>(items) : null;
if (beginIndex < 0) {
int i = -1;
for (Iterator it = stack.iterator(); it.hasNext();) {
final Object o = it.next();
if (o instanceof OTraverseRecordProcess) {
final ODocument record = ((OTraverseRecordProcess) o).getTarget();
if (iClassName == null || record.getSchemaClass().isSubClassOf(iClassName)) {
if (i <= beginIndex) {
if (items == 1)
return record;
else {
result.add(record);
if (result.size() >= items)
break;
}
}
i--;
}
}
}
} else {
int i = 0;
for (Iterator it = stack.descendingIterator(); it.hasNext();) {
final Object o = it.next();
if (o instanceof OTraverseRecordProcess) {
final ODocument record = ((OTraverseRecordProcess) o).getTarget();
if (iClassName == null || record.getSchemaClass().isSubClassOf(iClassName)) {
if (i >= beginIndex) {
if (items == 1)
return record;
else {
result.add(record);
if (result.size() >= items)
break;
}
}
i++;
}
}
}
}
if (items > 0 && result != null && !result.isEmpty())
return result;
return null;
}
}