/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.qp.operator;
import com.foundationdb.qp.row.ValuesRow;
import com.foundationdb.qp.row.Row;
import com.foundationdb.qp.rowtype.RowType;
import com.foundationdb.qp.rowtype.ValuesRowType;
import com.foundationdb.server.explain.CompoundExplainer;
import com.foundationdb.server.explain.ExplainContext;
import com.foundationdb.server.explain.std.CountOperatorExplainer;
import com.foundationdb.server.types.mcompat.mtypes.MNumeric;
import com.foundationdb.server.types.value.Value;
import com.foundationdb.util.ArgumentValidation;
import com.foundationdb.util.tap.InOutTap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collections;
import java.util.List;
import java.util.Set;
/**
<h1>Overview</h1>
Count_Default counts the number of rows of a specified RowType.
<h1>Arguments</h1>
<ul>
<li><b>RowType countType:</b> Type of rows to be counted.
</ul>
<h1>Behavior</h1>
The input rows whose type matches the countType are counted.
<h1>Output</h1>
A single row containing the row count (type long).
<h1>Assumptions</h1>
None.
<h1>Performance</h1>
This operator does no IO.
<h1>Memory Requirements</h1>
This operator keeps no rows in memory.
*/
class Count_Default extends Operator
{
// Object interface
@Override
public String toString()
{
return String.format("%s(%s)", getClass().getSimpleName(), countType);
}
// Operator interface
@Override
public List<Operator> getInputOperators()
{
return Collections.singletonList(inputOperator);
}
@Override
protected Cursor cursor(QueryContext context, QueryBindingsCursor bindingsCursor)
{
return new Execution(context, inputOperator.cursor(context, bindingsCursor));
}
@Override
public RowType rowType()
{
return resultType;
}
@Override
public void findDerivedTypes(Set<RowType> derivedTypes)
{
inputOperator.findDerivedTypes(derivedTypes);
derivedTypes.add(resultType);
}
@Override
public String describePlan()
{
return describePlan(inputOperator);
}
// Count_Default interface
public Count_Default(Operator inputOperator, RowType countType)
{
ArgumentValidation.notNull("countType", countType);
this.inputOperator = inputOperator;
this.countType = countType;
this.resultType = countType.schema().newValuesType(MNumeric.BIGINT.instance(false));
}
// Class state
private static final InOutTap TAP_OPEN = OPERATOR_TAP.createSubsidiaryTap("operator: Count_Default open");
private static final InOutTap TAP_NEXT = OPERATOR_TAP.createSubsidiaryTap("operator: Count_Default next");
private static final Logger LOG = LoggerFactory.getLogger(Count_Default.class);
// Object state
private final Operator inputOperator;
private final RowType countType;
private final ValuesRowType resultType;
@Override
public CompoundExplainer getExplainer(ExplainContext context)
{
return new CountOperatorExplainer(getName(), countType, resultType, inputOperator, context);
}
// Inner classes
private class Execution extends ChainedCursor
{
// Cursor interface
@Override
public void open()
{
TAP_OPEN.in();
try {
super.open();
count = 0;
} finally {
TAP_OPEN.out();
}
}
@Override
public Row next()
{
if (TAP_NEXT_ENABLED) {
TAP_NEXT.in();
}
try {
if (CURSOR_LIFECYCLE_ENABLED) {
CursorLifecycle.checkIdleOrActive(this);
}
checkQueryCancelation();
Row row = null;
while ((row == null) && this.isActive()) {
row = input.next();
if (row == null) {
setIdle();
row = new ValuesRow(resultType, new Value(MNumeric.BIGINT.instance(false), count));
} else if (row.rowType() == countType) {
row = null;
count++;
}
}
if (LOG_EXECUTION) {
LOG.debug("Count_Default: yield {}", row);
}
return row;
} finally {
if (TAP_NEXT_ENABLED) {
TAP_NEXT.out();
}
}
}
// Execution interface
Execution(QueryContext context, Cursor input)
{
super(context, input);
}
// Object state
private long count;
}
}