code: /*******************************************************************************
   * Copyright (c) 2009-2014 Richard Eckart de Castilho.
   *
   * 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.
   * 
   * Contributors:
   *     Richard Eckart de Castilho - initial API and implementation
   ******************************************************************************/
  package org.annolab.tt4j;
  
  import static java.io.File.separator;
  import static org.annolab.tt4j.Util.getSearchPaths;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  /**
   * Assume that TreeTagger is installed and available in the path.
   *
   * @author Richard Eckart de Castilho
   */
  public
  class DefaultExecutableResolver
  implements ExecutableResolver
  {
  	protected PlatformDetector _platform;
  	protected List<String> _additionalPaths = new ArrayList<String>();
  
  	public
  	void destroy()
  	{
  		// Do nothing
  	}
  
  	/**
  	 * Set additional paths that will be used for searching the TreeTagger
  	 * executable.
  	 *
  	 * @param aAdditionalPaths list of additional paths.
  	 * @see Util#getSearchPaths(List, String)
  	 */
  	public
  	void setAdditionalPaths(
  			final List<String> aAdditionalPaths)
  	{
  		_additionalPaths.clear();
  		_additionalPaths.addAll(aAdditionalPaths);
  	}
  
  	public
  	String getExecutable()
  	throws IOException
  	{
  		Set<String> searchedIn = new HashSet<String>();
  		for (final String p : getSearchPaths(_additionalPaths, "bin")) {
  			if (p == null) {
  				continue;
  			}
  
  			final File exe = new File(p+separator+"tree-tagger"+_platform.getExecutableSuffix());
  			searchedIn.add(exe.getAbsolutePath());
  			if (exe.exists()) {
  				return exe.getAbsolutePath();
  			}
  		}
  
  		throw new IOException("Unable to locate tree-tagger binary in the following locations " +
  				searchedIn + ". Make sure the environment variable 'TREETAGGER_HOME' or " +
  				"'TAGDIR' or the system property 'treetagger.home' point to the TreeTagger " +
  				"installation directory.");
  	}
  
  	/**
  	 * Set platform information.
  	 */
  	public
  	void setPlatformDetector(
  			final PlatformDetector aPlatform)
  	{
  		_platform = aPlatform;
  	}
  }
  