Bug 180189 Support in memory data set cache.
Currently, Design-Time Data Cache is stored on disks. By performance tests using ramdisk, we found that caching in physical memory can improve the performance of RunAndRender by 30%.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/api/DataEngineContext.java
/*******************************************************************************
 * Copyright (c) 2004 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Actuate Corporation  - initial API and implementation
 *******************************************************************************/
package org.eclipse.birt.data.engine.api;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Locale;
import org.eclipse.birt.core.archive.IDocArchiveReader;
import org.eclipse.birt.core.archive.IDocArchiveWriter;
import org.eclipse.birt.core.exception.BirtException;
import org.eclipse.birt.data.engine.core.DataException;
import org.eclipse.birt.data.engine.i18n.ResourceConstants;
import org.mozilla.javascript.Scriptable;
import com.ibm.icu.util.ULocale;
/**
 * Define in which context Data Engine is running. The context can be divided
 * into three types: generation, presentation and direct presentation. 
 */
public class DataEngineContext