/*
* Hibernate Validator, declare and validate application constraints
*
* License: Apache License, Version 2.0
* See the license.txt file in the root directory or <http://www.apache.org/licenses/LICENSE-2.0>.
*/
package org.hibernate.validator.internal.util.scriptengine;
import java.util.Map;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import javax.script.SimpleBindings;
/**
* A wrapper around JSR 223 {@link ScriptEngine}s. This class is thread-safe.
*
* @author Gunnar Morling
* @author Kevin Pollet <kevin.pollet@serli.com> (C) 2011 SERLI
*/
public class ScriptEvaluator {
private final ScriptEngine engine;
/**
* Creates a new script executor.
*
* @param engine The engine to be wrapped.
*/
public ScriptEvaluator(ScriptEngine engine) {
this.engine = engine;
}
/**
* Executes the given script, using the given variable bindings. The execution of the script happens either synchronized or
* unsynchronized, depending on the engine's threading abilities.
*
* @param script The script to be executed.
* @param bindings The bindings to be used.
*
* @return The script's result.
*
* @throws ScriptException In case of any errors during script execution.
*/
public Object evaluate(String script, Map<String, Object> bindings) throws ScriptException {
if ( engineAllowsParallelAccessFromMultipleThreads() ) {
return doEvaluate( script, bindings );
}
else {
synchronized ( engine ) {
return doEvaluate( script, bindings );
}
}
}
private Object doEvaluate(String script, Map<String, Object> bindings) throws ScriptException {
return engine.eval( script, new SimpleBindings( bindings ) );
}
/**
* Checks, whether the given engine is thread-safe or not.
*
* @return True, if the given engine is thread-safe, false otherwise.
*/
private boolean engineAllowsParallelAccessFromMultipleThreads() {
String threadingType = (String) engine.getFactory().getParameter( "THREADING" );
return "THREAD-ISOLATED".equals( threadingType ) || "STATELESS".equals( threadingType );
}
}