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/*
* VariableTable.java
*
* Created on April 12, 2000
*/
package com.sun.jdo.spi.persistence.support.sqlstore.query.jqlc;
import java.util.*;
import com.sun.jdo.spi.persistence.utility.I18NHelper;
import com.sun.jdo.api.persistence.support.JDOQueryException;
import com.sun.jdo.api.persistence.support.JDOUnsupportedOptionException;
import com.sun.jdo.api.persistence.support.JDOFatalInternalException;
/**
* The variable table
*
* @author Michael Bouschen
* @version 0.1
*/
public class VariableTable
{
/**
* I18N support
*/
protected final static ResourceBundle messages =
I18NHelper.loadBundle(VariableTable.class);
/**
* A VarInfo consists of two info fields:
* - constraint: the variable is constraint with the specified expr
* - used: the variable is used
*/
static class VarInfo
{
/**
* The constraint expression.
*/
JQLAST constraint;
/**
* Set of JQLAST nodes denoting an access of this variable.
*/
Set used;
/**
* Dependency for this variable.
* The constraint for this variable may use another variable.
*/
String dependsOn;
/**
* Flag whether this varInfo is checked already (see checkConstraints)
*/
int status;
static final int UNCHECKED = 0;
static final int IN_PROGRESS = 1;
static final int CHECKED = 2;
VarInfo()
{
this.constraint = null;
this.used = new HashSet();
this.dependsOn = null;
this.status = UNCHECKED;
}
VarInfo(VarInfo other)
{
this.constraint = other.constraint;
this.used = new HashSet(other.used);
this.dependsOn = other.dependsOn;
this.status = other.status;
}
}
/** */
private ErrorMsg errorMsg;
/** List of names of declared variables. */
private List declaredVars;
/** Map of variable infos. */
private Map varInfos;
/**
* Create an empty variable table
*/
public VariableTable(ErrorMsg errorMsg)
{
this.errorMsg = errorMsg;
declaredVars = new ArrayList();
varInfos = new HashMap();
}
/**
* Create a variable table initialized with the entries of the other variable table.
* The constructor creates copies of the values stored in the map (instances of class VarInfo).
*/
public VariableTable(VariableTable other)
{
errorMsg = other.errorMsg;
declaredVars = other.declaredVars;
varInfos = new HashMap();
for (Iterator i = other.varInfos.entrySet().iterator(); i.hasNext();)
{
Map.Entry entry = (Map.Entry)i.next();
varInfos.put(entry.getKey(), new VarInfo((VarInfo)entry.getValue()));
}
}
/**
* Creates a new entry in the variable table with the specified name as key and
* an empty value.
*/
public void add(String name)
{
declaredVars.add(name);
// init var entry as not constraint and unused
varInfos.put(name, new VarInfo());
}
/**
* Mark the specified variable as used.
* The method sets the info field of the VarInfo object to true.
*/
public void markUsed(JQLAST variable, String dependendVar)
{
String name = variable.getText();
VarInfo entry = (VarInfo)varInfos.get(name);
if (entry == null)
throw new JDOFatalInternalException(I18NHelper.getMessage(messages,
"jqlc.variabletable.markused.varnotfound", //NOI18N
name));
entry.used.add(variable);
if (dependendVar != null)
{
VarInfo dependendVarInfo = (VarInfo)varInfos.get(dependendVar);
if (dependendVarInfo.dependsOn != null)
throw new JDOFatalInternalException(I18NHelper.getMessage(
messages,
"jqlc.variabletable.markused.multidep", //NOI18N
dependendVar, dependendVarInfo.dependsOn, name));
dependendVarInfo.dependsOn = name;
}
}
/**
* Mark the specified variable as constaint with the specified expr.
* The method sets the constraint field of the VarInfo object to true.
*/
public void markConstraint(JQLAST variable, JQLAST expr)
{
String name = variable.getText();
VarInfo entry = (VarInfo)varInfos.get(name);
if (entry == null)
throw new JDOFatalInternalException(I18NHelper.getMessage(
messages,
"jqlc.variabletable.markconstraint.varnotfound", //NOI18N
name));
String old = (entry.constraint==null ? null : entry.constraint.getText());
if ((old != null) && !old.equals(expr.getText()))
{
errorMsg.unsupported(variable.getLine(), variable.getColumn(),
I18NHelper.getMessage(messages, "jqlc.variabletable.markconstraint.multiple", //NOI18N
name));
}
entry.constraint = expr;
}
/**
* Merges the specified variable table (other) into this variable table.
*/
public void merge(VariableTable other)
{
for (Iterator i = declaredVars.iterator(); i.hasNext();)
{
String name = (String)i.next();
VarInfo info = (VarInfo)varInfos.get(name);
VarInfo otherInfo = (VarInfo)other.varInfos.get(name);
// copy other info if this info is empty
if ((info.constraint == null) && (info.used.size() == 0))
{
info.constraint = otherInfo.constraint;
info.used = otherInfo.used;
info.dependsOn = otherInfo.dependsOn;
info.status = otherInfo.status;
continue;
}
// do nothing if otherInfo is empty
if ((otherInfo.constraint == null) && (otherInfo.used.size() == 0))
{
continue;
}
// constraint check
// If both variables tables include constraints they have to be the same
if ((info.constraint != null) && (otherInfo.constraint != null))
{
if (!otherInfo.constraint.getText().equals(info.constraint.getText()))
{
throw new JDOUnsupportedOptionException(
I18NHelper.getMessage(messages, "jqlc.variabletable.merge.different", name)); //NOI18N
}
}
// If at least one variable table does not define constraint,
// nullify the constaint in this variable table
else
{
info.constraint = null;
info.dependsOn = null;
info.status = VarInfo.UNCHECKED;
}
// copy otherInfo.used to this used list
info.used.addAll(otherInfo.used);
}
}
/**
*
*/
public void checkConstraints()
{
// iterate declaredVars to check the variables in the order they are declared
for (Iterator i = declaredVars.iterator(); i.hasNext();)
{
String name = (String)i.next();
VarInfo info = (VarInfo)varInfos.get(name);
checkConstraint(name, info);
}
}
protected void checkConstraint(String variable, VarInfo info)
{
switch (info.status)
{
case VarInfo.UNCHECKED:
// if unchecked, start checking
info.status = VarInfo.IN_PROGRESS;
break;
case VarInfo.IN_PROGRESS:
// if this VarInfo is currently processed we have a cyclic dependency
throw new JDOUnsupportedOptionException(
I18NHelper.getMessage(messages, "jqlc.variabletable.checkconstraint.cycle", // NOI18N
variable));
case VarInfo.CHECKED:
// if alreday checked just return
return;
}
if (info.dependsOn != null)
{
VarInfo dependendVarInfo = (VarInfo)varInfos.get(info.dependsOn);
checkConstraint(info.dependsOn, dependendVarInfo);
}
if ((info.constraint != null) && (info.used.size() == 0))
{
throw new JDOUnsupportedOptionException(
I18NHelper.getMessage(messages, "jqlc.variabletable.checkconstraint.unused", //NOI18N
variable));
}
attachConstraintToUsedAST(info);
info.status = VarInfo.CHECKED;
}
/**
*
*/
protected void attachConstraintToUsedAST(VarInfo info)
{
for (Iterator i = info.used.iterator(); i.hasNext();)
{
JQLAST varNode = (JQLAST)i.next();
if (varNode.getFirstChild() == null)
varNode.setFirstChild(JQLAST.Factory.getInstance().dupTree(info.constraint));
}
}
}
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