DkproContext.java

/*
 * Copyright 2010
 * Ubiquitous Knowledge Processing (UKP) Lab
 * Technische Universität Darmstadt
 * 
 * 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 de.tudarmstadt.ukp.dkpro.core.api.resources;

import java.io.File;
import java.io.IOException;

/**
 * Runtime context for DKPro.
 *
 */
public
class DkproContext
{
	public static final String ENV_DKPRO_HOME = "DKPRO_HOME";
	public static final String DEFAULT_ENCODING = "UTF-8";

	private static DkproContext context;

	/**
	 * The the current context.
	 *
	 * @return the context.
	 */
	public static synchronized
	DkproContext getContext()
	{
		if (context == null) {
			context = new DkproContext();
		}
		return context;
	}

	/**
	 * Get the workspace directory.
	 *
	 * @return the workspace directory.
	 * @throws IOException if the workspace cannot be obtained
	 */
	public
	File getWorkspace()
	throws IOException
	{
		if (System.getenv(ENV_DKPRO_HOME) != null) {
			File f = new File(System.getenv(ENV_DKPRO_HOME));
			f.mkdirs();
			return f;
		}

		throw new IOException("Environment variable ["+ENV_DKPRO_HOME+"] not set");
	}

	/**
	 * Get the workspace directory for a particular class.
	 *
	 * @param aClass a class.
	 * @return the class workspace.
	 * @throws IOException if the workspace cannot be obtained.
	 */
	public
	File getWorkspace(
			final Class<?> aClass)
	throws IOException
	{
		return getWorkspace(aClass.getName());
	}

	/**
	 * Get the workspace directory for a particular topic.
	 *
	 * @param aTopic the topic ID.
	 * @return the topic workspace.
	 * @throws IOException if the workspace cannot be obtained.
	 */
	public
	File getWorkspace(
			final String aTopic)
	throws IOException
	{
		File f = new File(getWorkspace(), aTopic);
		f.mkdirs();
		return f;
	}
}