/*
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
Redistribution and use in source and binary forms, with or without modifica-
tion, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. The end-user documentation included with the redistribution, if any, must
include the following acknowledgment: "This product includes software
developed by the Apache Software Foundation (http://www.apache.org/)."
Alternately, this acknowledgment may appear in the software itself, if
and wherever such third-party acknowledgments normally appear.
4. The names "Apache Cocoon" and "Apache Software Foundation" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
apache@apache.org.
5. Products derived from this software may not be called "Apache", nor may
"Apache" appear in their name, without prior written permission of the
Apache Software Foundation.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This software consists of voluntary contributions made by many individuals
on behalf of the Apache Software Foundation and was originally created by
Stefano Mazzocchi <stefano@apache.org>. For more information on the Apache
Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.cocoon.components.variables;
import java.util.ArrayList;
import java.util.List;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.ServiceSelector;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.components.ContextHelper;
import org.apache.cocoon.components.modules.input.InputModule;
import org.apache.cocoon.sitemap.PatternException;
/**
* Prepared implementation of {@link VariableResolver} for fast evaluation.
*
* @author <a href="mailto:sylvain@apache.org">Sylvain Wallez</a>
* @author <a href="mailto:tcurdt@apache.org">Torsten Curdt</a>
* @author <a href="mailto:cziegeler@apache.org">Carsten Ziegeler</a>
* @version CVS $Id: PreparedVariableResolver.java,v 1.3 2003/10/20 13:36:42 cziegeler Exp $
*/
public class PreparedVariableResolver
extends NOPVariableResolver {
protected ServiceManager manager;
protected ServiceSelector selector;
protected Context context;
protected List items = new ArrayList();
// Special constants used for levels
static final int LITERAL = -2;
static final int THREADSAFE_MODULE = -3;
static final int STATEFUL_MODULE = -4;
private static final Integer LITERAL_OBJ = new Integer(LITERAL);
private static final Integer THREADSAFE_MODULE_OBJ = new Integer(THREADSAFE_MODULE);
private static final Integer STATEFUL_MODULE_OBJ = new Integer(STATEFUL_MODULE);
public PreparedVariableResolver(String expr, ServiceManager manager, Context context)
throws PatternException {
super(null);
this.expression = expr;
this.manager = manager;
this.context = context;
int length = expr.length();
int prev = 0; // position after last closing brace
compile : while(prev < length) {
// find next unescaped '{'
int pos = prev;
while(pos < length &&
(pos = expr.indexOf('{', pos)) != -1 &&
(pos != 0 && expr.charAt(pos - 1) == '\\')) {
pos++;
}
if (pos >= length || pos == -1) {
// no more braces : add ending literal
if (prev < length) {
addLiteral(expr.substring(prev));
}
break compile;
}
// Pass closing brace
pos++;
// Add litteral strings between closing and next opening brace
if (prev < pos-1) {
addLiteral(expr.substring(prev, pos - 1));
}
int end = expr.indexOf('}', pos);
if (end == -1) {
throw new PatternException("Unmatched '{' in " + expr);
}
int colon = expr.indexOf(':', pos);
if (colon != -1 && colon < end) {
String module = expr.substring(pos, colon);
String variable = expr.substring(colon + 1, end);
// Module used
addModuleVariable(module, variable);
} else {
throw new PatternException("Unknown variable format " + expr.substring(pos, end));
}
prev = end + 1;
}
}
protected void addLiteral(String litteral) {
this.items.add(LITERAL_OBJ);
this.items.add(litteral);
}
protected void addModuleVariable(String moduleName, String variable) throws PatternException {
if (this.selector == null) {
try {
// First access to a module : lookup selector
this.selector = (ServiceSelector)this.manager.lookup(InputModule.ROLE + "Selector");
} catch(ServiceException ce) {
throw new PatternException("Cannot access input modules selector", ce);
}
}
// Get the module
InputModule module;
try {
module = (InputModule)this.selector.select(moduleName);
} catch(ServiceException ce) {
throw new PatternException("Cannot get InputModule named '" + moduleName +
"' in expression '" + this.expression + "'", ce);
}
// Is this module threadsafe ?
if (module instanceof ThreadSafe) {
this.items.add(THREADSAFE_MODULE_OBJ);
this.items.add(module);
this.items.add(variable);
} else {
// Statefull module : release it
this.selector.release(module);
this.items.add(STATEFUL_MODULE_OBJ);
this.items.add(moduleName);
this.items.add(variable);
}
}
public String resolve()
throws PatternException {
StringBuffer result = new StringBuffer();
for (int i = 0; i < this.items.size(); i++) {
int type = ((Integer)this.items.get(i)).intValue();
switch(type) {
case LITERAL :
result.append(items.get(++i));
break;
case THREADSAFE_MODULE :
{
InputModule module = (InputModule)items.get(++i);
String variable = (String)items.get(++i);
try {
Object value = module.getAttribute(variable, null, ContextHelper.getObjectModel(this.context));
if (value != null) {
result.append(value);
}
} catch(ConfigurationException confEx) {
throw new PatternException("Cannot get variable '" + variable +
"' in expression '" + this.expression + "'", confEx);
}
}
break;
case STATEFUL_MODULE :
{
InputModule module = null;
String moduleName = (String)items.get(++i);
String variableName = (String)items.get(++i);
try {
module = (InputModule)this.selector.select(moduleName);
Object value = module.getAttribute(variableName, null, ContextHelper.getObjectModel(this.context));
if (value != null) {
result.append(value);
}
} catch(ServiceException compEx) {
throw new PatternException("Cannot get module '" + moduleName +
"' in expression '" + this.expression + "'", compEx);
} catch(ConfigurationException confEx) {
throw new PatternException("Cannot get variable '" + variableName +
"' in expression '" + this.expression + "'", confEx);
} finally {
this.selector.release(module);
}
}
break;
}
}
return result.toString();
}
public void dispose() {
super.dispose();
if (this.selector != null) {
for (int i = 0; i < this.items.size(); i++) {
int type = ((Integer) this.items.get(i)).intValue();
switch (type) {
case LITERAL:
i++; // literal string
break;
case THREADSAFE_MODULE:
i++; // module
this.selector.release(this.items.get(i));
i++; // variable
break;
case STATEFUL_MODULE:
i += 2; // module name, variable
break;
default:
}
}
this.manager.release(this.selector);
this.selector = null;
this.manager = null;
}
}
}