/*
* Copyright 2011 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.hadoop.scripting;
import java.io.IOException;
import java.util.Collections;
import java.util.Map;
import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.SimpleBindings;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.scripting.ScriptCompilationException;
import org.springframework.scripting.ScriptSource;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
/**
* Jsr233/javax.scripting implementation of {@link ScriptEvaluator}.
*
* @author Costin Leau
*/
class Jsr223ScriptEvaluator implements ScriptEvaluator {
private final Log log = LogFactory.getLog(getClass());
private String language;
private String extension;
private ClassLoader classLoader;
/**
* Constructs a new <code>Jsr223ScriptEvaluator</code> instance.
*/
public Jsr223ScriptEvaluator() {
this(null);
};
/**
* Constructs a new <code>Jsr223ScriptEvaluator</code> instance.
*
* @param classLoader class loader to use
*/
public Jsr223ScriptEvaluator(ClassLoader classLoader) {
this.classLoader = classLoader;
}
@Override
public Object evaluate(ScriptSource script) {
return evaluate(script, Collections.<String, Object> emptyMap());
}
@Override
public Object evaluate(ScriptSource script, Map<String, Object> arguments) {
ScriptEngine engine = discoverEngine(script, arguments);
Bindings bindings = (!CollectionUtils.isEmpty(arguments) ? new SimpleBindings(arguments) : null);
try {
return (bindings == null ? engine.eval(script.getScriptAsString()) : engine.eval(
script.getScriptAsString(), bindings));
} catch (IOException ex) {
throw new ScriptCompilationException(script, "Cannot access script", ex);
} catch (ScriptException ex) {
throw new ScriptCompilationException(script, "Execution failure", ex);
}
}
protected ScriptEngine discoverEngine(ScriptSource script, Map<String, Object> arguments) {
ScriptEngineManager engineManager = new ScriptEngineManager(classLoader);
ScriptEngine engine = null;
if (StringUtils.hasText(language)) {
engine = engineManager.getEngineByName(language);
}
else {
// make use the extension (enhanced ScriptSource interface)
Assert.hasText(extension, "no language or extension specified");
engine = engineManager.getEngineByExtension(extension);
}
Assert.notNull(engine, "No suitable engine found for "
+ (StringUtils.hasText(language) ? "language " + language : "extension " + extension));
if (log.isDebugEnabled()) {
ScriptEngineFactory factory = engine.getFactory();
log.debug(String.format("Using ScriptEngine %s (%s), language %s (%s)", factory.getEngineName(),
factory.getEngineVersion(), factory.getLanguageName(), factory.getLanguageVersion()));
}
return engine;
}
/**
* Sets the extension of the language meant for evaluation the scripts..
*
* @param extension The extension to set.
*/
public void setExtension(String extension) {
this.extension = extension;
}
/**
* Sets the name of language meant for evaluation the scripts.
*
* @param language The language to set.
*/
public void setLanguage(String language) {
this.language = language;
}
}