/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.processor.xml;
import java.util.List;
import java.util.Map;
import org.teiid.client.plan.PlanNode;
import org.teiid.common.buffer.BlockedException;
import org.teiid.core.TeiidComponentException;
import org.teiid.core.TeiidProcessingException;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.util.VariableContext;
/**
* Loop instruction on the result set execute before this instruction.
*/
public class JoinedWhileInstruction extends WhileInstruction {
private Integer mappingClassNumber;
private ElementSymbol mappingClassSymbol;
private String originalResultSet;
/**
* Constructor for WhileInstruction.
*/
public JoinedWhileInstruction(String rsName,
Integer mappingClassNumber,
ElementSymbol mappingClassSymbol, String originalResultSet) {
super(rsName);
this.mappingClassNumber = mappingClassNumber;
this.mappingClassSymbol = mappingClassSymbol;
this.originalResultSet = originalResultSet;
}
/**
* @see ProcessorInstruction#process(ProcessorEnvironment)
*/
public XMLContext process(XMLProcessorEnvironment env,
XMLContext context) throws BlockedException,
TeiidComponentException,
TeiidProcessingException {
List values = context.getCurrentRow(getResultSetName());
if (values == null) {
env.incrementCurrentProgramCounter();
return context;
}
List outputElements = context.getOutputElements(getResultSetName());
int index = outputElements.indexOf(mappingClassSymbol);
Object value = values.get(index);
VariableContext varContext = context.getVariableContext();
// move on to the next row and don't push the program
if (value == null) {
if (Boolean.TRUE.equals(getFirst(varContext))) {
context.getNextRow(getResultSetName());
}
setFirst(varContext, Boolean.TRUE);
env.incrementCurrentProgramCounter();
return context;
}
boolean canConsume = true;
// TODO: this is very inefficient. each root should check only its values and pass that value through the context
// TODO: likewise the context update below should also only involve the columns from this context
if (!Boolean.TRUE.equals(getFirst(varContext))) {
Map previousValues = getPreviousValues(varContext);
if (previousValues != null) {
for (int i = 0; i < index - 1 && canConsume; i++) {
Object previousValue = previousValues.get(outputElements.get(i));
Object currentValue = values.get(i);
if (previousValue != null) {
if (!previousValue.equals(currentValue)) {
canConsume = false;
}
} else if (currentValue != null) {
canConsume = false;
}
}
}
}
// consume this row only if the parent values are the same
if (value.equals(mappingClassNumber) && canConsume) {
//it is not necessary to push the values back into the context here
setPreviousValues(varContext, context.getReferenceValues());
pushProgram(env, context, values);
setFirst(varContext, Boolean.FALSE);
} else {
setFirst(varContext, Boolean.TRUE);
env.incrementCurrentProgramCounter();
return context;
}
return context;
}
Boolean getFirst(VariableContext varContext) {
return (Boolean)varContext.getValue(new ElementSymbol("$" + getResultSetName() + "$" + originalResultSet + "$first")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
void setFirst(VariableContext varContext, Boolean value) {
varContext.setValue(new ElementSymbol("$" + getResultSetName() + "$" + originalResultSet + "$first"), value); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
public String toString() {
return "JOINED " + originalResultSet + " " + super.toString(); //$NON-NLS-1$ //$NON-NLS-2$
}
public PlanNode getDescriptionProperties() {
return new PlanNode("JOINED LOOP"); //$NON-NLS-1$
}
}