/*
* 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.sql.util;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.teiid.core.TeiidComponentException;
import org.teiid.query.QueryPlugin;
import org.teiid.query.sql.symbol.ElementSymbol;
public class VariableContext {
// map between variables and their values
private Map variableMap = new LinkedHashMap();
// reference to the parent variable context
private VariableContext parentContext;
private boolean delegateSets;
/**
* Constructor for VariableContext.
*/
public VariableContext() {
this(false);
}
public VariableContext(boolean delegateSets) {
this.delegateSets = delegateSets;
}
public void setGlobalValue(String variable, Object value) {
if (this.parentContext != null) {
this.parentContext.setGlobalValue(variable, value);
} else {
variableMap.put(variable, value);
}
}
public Object getGlobalValue(String variable) throws TeiidComponentException {
if (this.parentContext != null) {
return this.parentContext.getGlobalValue(variable);
}
Object value = variableMap.get(variable);
if (value == null && !variableMap.containsKey(variable)) {
throw new TeiidComponentException("ERR.015.006.0033", QueryPlugin.Util.getString("ERR.015.006.0033", variable, "No value was available")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
return value;
}
/**
* Set the value for the given, if the variable already exits replaces its value
* with the given value else adds a new variable to the map.
* @param variable The <code>ElementSymbol</code> to be added as a variable.
* @param value The value to be set for the given variable.
*/
public void setValue(ElementSymbol variable, Object value) {
if (delegateSets && parentContext != null && parentContext.containsVariable(variable)) {
parentContext.setValue(variable, value);
} else {
variableMap.put(variable, value);
}
}
/**
* Get the value for the given variable, if the variable exits in the current
* context just return the value of the variable else lookup the parent context
* and return the value of the variable.
* @param variable The <code>ElementSymbol</code> whose value needs to be returned.
* @return The value of the given variable
*/
public Object getValue(ElementSymbol variable) {
if (variableMap.containsKey(variable)) {
return variableMap.get(variable);
}
// if the variable is not present in the current variablecontext
// look up the parent context
if(this.parentContext != null) {
return this.parentContext.getValue(variable);
}
return null;
}
/**
* Set the parent variable context for this variable context, when looking up
* the variable's value, if the variable is not present in the current context,
* the parent context is lookedup.
* @param parent The parent <code>VariableContext</code>.
*/
public void setParentContext(VariableContext parent) {
this.parentContext = parent;
}
/**
* Get the parent context for this variable context. When looking up
* the variable's value, if the variable is not present in the current context,
* the parent context is lookedup.
* @return The parent <code>VariableContext</code>.
*/
public VariableContext getParentContext() {
return this.parentContext;
}
/** Helper Methods */
public void getFlattenedContextMap(Map values) {
if(this.parentContext != null) {
this.parentContext.getFlattenedContextMap(values);
}
values.putAll(this.variableMap);
}
/**
* Check if this context or any of it's parent contexts contain this variable
* @param variable The variable which may be present on this context
* @return A boolean value indiating if the given variable is present on this context
* or any of it's parent contexts.
*/
public boolean containsVariable(ElementSymbol variable) {
if(!variableMap.containsKey(variable)) {
if(this.parentContext != null) {
return this.parentContext.containsVariable(variable);
}
return false;
}
return true;
}
/**
* Check if the current context and its parents contain any variables
* @return A boolean bollean value indicating if this context is empty
*/
public boolean isEmpty() {
if(variableMap.isEmpty()) {
if(this.parentContext != null) {
return this.parentContext.isEmpty();
}
return true;
}
return false;
}
public Object remove(ElementSymbol symbol) {
if (!this.variableMap.containsKey(symbol)) {
if (this.parentContext != null) {
return this.parentContext.remove(symbol);
}
return null;
}
return this.variableMap.remove(symbol);
}
@Override
public String toString() {
return this.variableMap.toString();
}
public void clear() {
this.variableMap.clear();
}
public void putAll(VariableContext other) {
this.variableMap.putAll(other.variableMap);
}
public List<Object> getLocalValues() {
return new ArrayList<Object>(this.variableMap.values());
}
}