nl.b3p.catalog.arcgis.ArcObjectsLinker.java Source code

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Here is the source code for nl.b3p.catalog.arcgis.ArcObjectsLinker.java

Source

/*
 * Copyright (C) 2011 B3Partners B.V.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package nl.b3p.catalog.arcgis;

import java.io.File;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Deze class voegt arcobjects.jar toe aan de system classloader. Belangrijk is
 * dat de methode linkArcObjects() succesvol moet zijn aangeroepen voordat ook
 * maar een enkele class met een "import com.esri" statement wordt geladen.
 * 
 * arcobjects.ar kan namelijk niet meegeleverd worden met een applicatie. Als
 * in een applicatie ArcObjects optioneel is is het mogelijk om het laden van 
 * classes die ESRI packages importeren te vermijden.
 * 
 * Ook indien ArcObjects wel vereist is is het op deze manier linken van 
 * ArcObjects mogelijk op basis van environment variabelen van de ESRI 
 * installatie en is het mogelijk om foutmeldingen te geven. Het is ook simpeler
 * dan de -classpath parameter van de JVM of een Tomcat classloader in te stellen.
 * 
 * @author Matthijs Laan
 */
public class ArcObjectsLinker {
    private static final Log log = LogFactory.getLog(ArcObjectsLinker.class);

    private static List<String> homeEnvVars = Arrays
            .asList(new String[] { "AGSSERVERJAVA", "AGSENGINEJAVA", "AGSDESKTOPJAVA", "ARCGISHOME" });

    public static void link() throws Exception {
        link(null);
    }

    public static void link(String arcObjectsHome) throws Exception {

        if (arcObjectsHome == null) {
            for (String s : homeEnvVars) {
                arcObjectsHome = System.getenv(s);
                if (arcObjectsHome != null) {
                    log.info("Using environment variable " + s + " to find ArcObjects");
                    break;
                }
            }
        }
        if (arcObjectsHome == null) {
            throw new Exception("Could not find ArcObjects home in environment variables " + homeEnvVars + ". "
                    + (System.getProperty("os.name").toLowerCase().indexOf("win") > -1
                            ? "ArcGIS Engine Runtime or ArcGIS Desktop must be installed"
                            : "ArcGIS Engine Runtime must be installed"));
        }

        // The directory can be set to a JAR itself, the directory arcobjects.jar
        // is in, or (as in the environment variables) the path with "java/lib" 
        // subdirectories with arcobjects.jar in it (some reports ArcGIS Server
        // 10.1 not having these java/lib subdirs).

        File jarFile = null;

        if (arcObjectsHome.endsWith(".jar")) {
            jarFile = new File(arcObjectsHome);
            if (jarFile.exists()) {
                log.info(String.format("Using full path to ArcObjects JAR file: %s", jarFile.getAbsolutePath()));
            } else {
                jarFile = null;
            }
        }

        if (jarFile == null) {
            String jarPath = arcObjectsHome + File.separator + "arcobjects.jar";
            jarFile = new File(jarPath);

            if (jarFile.exists()) {
                log.info(String.format("Using arcobjects.jar found in directory: %s", jarFile.getAbsolutePath()));
            } else {
                jarFile = null;
            }
        }

        if (jarFile == null) {
            String jarPath = arcObjectsHome + File.separator + "java" + File.separator + "lib" + File.separator
                    + "arcobjects.jar";
            jarFile = new File(jarPath);

            if (!jarFile.exists()) {
                throw new Exception(
                        "Error: could not find arcobjects.jar at path \"" + jarFile.getAbsolutePath() + "\"");
            } else {
                log.info(String.format("Using ArcObjects home \"%s\"", arcObjectsHome));
            }
        }

        // Deze hack is afkomstig van ESRI voorbeelden...

        // Helps load classes and resources from a search path of URLs
        URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
        Class<URLClassLoader> sysclass = URLClassLoader.class;

        try {
            Method method = sysclass.getDeclaredMethod("addURL", new Class[] { URL.class });
            method.setAccessible(true);
            method.invoke(sysloader, new Object[] { jarFile.toURI().toURL() });
        } catch (Throwable throwable) {
            throw new Exception("Could not add arcobjects.jar to system classloader", throwable);
        }
    }
}