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Splout is a read only, horizontally scalable SQL database that plays well with Hadoop.

There is a newer version: 0.3.0

package com.splout.db.hadoop;

/*
 * #%L
 * Splout SQL Hadoop library
 * %%
 * Copyright (C) 2012 Datasalt Systems S.L.
 * %%
 * 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.
 * #L%
 */

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.Scriptable;

/**
 * An engine for embedding JavaScript into Java using Rhino, etc.
 */
public class JavascriptEngine {
	
	private Context cx;
	private Scriptable scope;
	
	public JavascriptEngine(String javascript) throws Throwable {
		try {
			cx = Context.enter();
			scope = cx.initStandardObjects();
			cx.evaluateString(scope, javascript, "", 1, null);
		} catch(Throwable t) {
			// https://developer.mozilla.org/en-US/docs/Rhino/Scopes_and_Contexts
			Context.exit();
			cx = null;
			throw t;
		}
	}

	public String execute(String methodName, Object... params) throws Throwable {
		if(cx == null) {
			throw new IllegalStateException("Can't execute a function, context is null!");
		}
		Object fObj = scope.get(methodName, scope);
	  Function f = (Function)fObj;
		return Context.toString(f.call(cx, scope, scope, params));
	}
	
	public void close() {
		if(cx != null) {
			Context.exit();
		}
	}
}