package com.espertech.esper.core;
import com.espertech.esper.epl.variable.VariableService;
import com.espertech.esper.epl.variable.VariableReader;
import com.espertech.esper.util.ManagedReadWriteLock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.*;
/**
* Service for holding references between statements and their variable use.
*/
public class StatementVariableRefImpl implements StatementVariableRef
{
private static final Log log = LogFactory.getLog(StatementVariableRefImpl.class);
private final ManagedReadWriteLock mapLock;
private final HashMap<String, Set<String>> variableToStmt;
private final HashMap<String, Set<String>> stmtToVariable;
private final VariableService variableService;
private final Set<String> configuredVariables;
/**
* Ctor.
* @param variableService variables
*/
public StatementVariableRefImpl(VariableService variableService)
{
variableToStmt = new HashMap<String, Set<String>>();
stmtToVariable = new HashMap<String, Set<String>>();
mapLock = new ManagedReadWriteLock("StatementVariableRefImpl", false);
this.variableService = variableService;
configuredVariables = new HashSet<String>();
for (Map.Entry<String, VariableReader> entry : variableService.getVariables().entrySet()) {
configuredVariables.add(entry.getKey());
}
}
public void addConfiguredVariable(String variableName) {
configuredVariables.add(variableName);
}
public void removeConfiguredVariable(String variableName) {
configuredVariables.remove(variableName);
}
public void addReferences(String statementName, Set<String> variablesReferenced)
{
if ((variablesReferenced == null) || (variablesReferenced.isEmpty()))
{
return;
}
mapLock.acquireWriteLock();
try
{
for (String ref : variablesReferenced)
{
addReference(statementName, ref);
}
}
finally
{
mapLock.releaseWriteLock();
}
}
public void removeReferencesStatement(String statementName)
{
mapLock.acquireWriteLock();
try
{
Set<String> variables = stmtToVariable.remove(statementName);
if (variables != null)
{
for (String variable : variables)
{
removeReference(statementName, variable);
}
}
}
finally
{
mapLock.releaseWriteLock();
}
}
public void removeReferencesVariable(String name)
{
mapLock.acquireWriteLock();
try
{
Set<String> statementNames = variableToStmt.remove(name);
if (statementNames != null)
{
for (String statementName : statementNames)
{
removeReference(statementName, name);
}
}
}
finally
{
mapLock.releaseWriteLock();
}
}
public boolean isInUse(String variable)
{
mapLock.acquireReadLock();
try {
return variableToStmt.containsKey(variable);
}
finally {
mapLock.releaseReadLock();
}
}
public Set<String> getStatementNamesForVar(String variableName)
{
mapLock.acquireReadLock();
try {
Set<String> variables = variableToStmt.get(variableName);
if (variables == null)
{
return Collections.EMPTY_SET;
}
return Collections.unmodifiableSet(variables);
}
finally {
mapLock.releaseReadLock();
}
}
private void addReference(String statementName, String variableName)
{
// add to variables
Set<String> statements = variableToStmt.get(variableName);
if (statements == null)
{
statements = new HashSet<String>();
variableToStmt.put(variableName, statements);
}
statements.add(statementName);
// add to statements
Set<String> variables = stmtToVariable.get(statementName);
if (variables == null)
{
variables = new HashSet<String>();
stmtToVariable.put(statementName, variables);
}
variables.add(variableName);
}
private void removeReference(String statementName, String variableName)
{
// remove from variables
Set<String> statements = variableToStmt.get(variableName);
if (statements != null)
{
if (!statements.remove(statementName))
{
log.info("Failed to find statement name '" + statementName + "' in collection");
}
if (statements.isEmpty())
{
variableToStmt.remove(variableName);
if (!configuredVariables.contains(variableName)) {
variableService.removeVariable(variableName);
}
}
}
// remove from statements
Set<String> variables = stmtToVariable.get(statementName);
if (variables != null)
{
if (!variables.remove(variableName))
{
log.info("Failed to find variable '" + variableName + "' in collection");
}
if (variables.isEmpty())
{
stmtToVariable.remove(statementName);
}
}
}
/**
* For testing, returns the mapping of variable name to statement names.
* @return mapping
*/
protected HashMap<String, Set<String>> getVariableToStmt()
{
return variableToStmt;
}
/**
* For testing, returns the mapping of statement names to variable names.
* @return mapping
*/
protected HashMap<String, Set<String>> getStmtToVariable()
{
return stmtToVariable;
}
}