path: root/JLanguageTool/src/java/de/danielnaber/languagetool/databroker/DefaultResourceDataBroker.java

/* LanguageTool, a natural language style checker 
 * Copyright (C) 2006 Daniel Naber (http://www.danielnaber.de)
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */
package de.danielnaber.languagetool.databroker;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.security.Permission;

import de.danielnaber.languagetool.JLanguageTool;

/**
 * Responsible for getting any items from the grammar checker's resource
 * directories. This default data broker assumes that they are accessible
 * directly via class-path and the directory names are like specified in:
 * 
 * <ul style="list-type: circle">
 * <li>{@link ResourceDataBroker#RESOURCE_DIR}</li>
 * <li>{@link ResourceDataBroker#RULES_DIR}</li>
 * </ul>
 * <p>
 * 
 * If you'd like to determine another resource directory location this default
 * data broker provides proper methods.
 * Assuming your {@code /rules} and {@code /resource} directories are accessible
 * via class-path with following path information:
 * 
 * <ul style="list-type: circle">
 * <li>{@code /res/grammarchecker/rulesdirname}</li>
 * <li>{@code /res/grammarchecker/resourcedirname}</li>
 * </ul>
 * 
 * In this case you have to invoke the methods
 * {@link ResourceDataBroker#setRulesDir(String)} and
 * {@link ResourceDataBroker#setResourceDir(String)} with following arguments:
 * 
 * <ul style="list-type: circle">
 * <li>{@code /res/grammarchecker/rulesdirname}</li>
 * <li>{@code /res/grammarchecker/resourcedirname}</li>
 * </ul>
 * <p>
 * 
 * Make sure that you never obtain any grammar checker resources by calling
 * {@code Object.class.getResource(String)} or {@code
 * Object.class.getResourceAsStream(String)} directly. If you would like to
 * obtain something from these directories do always use
 * {@link JLanguageTool#getDataBroker()} which provides proper methods for
 * reading the directories above.
 * <p>
 * 
 * For example, if you want to get the {@link URL} of {@code
 * /rules/de/grammar.xml} just invoke
 * {@link ResourceDataBroker#getFromRulesDirAsUrl(String)} and pass {@code
 * /de/grammar.xml} as a string. Note: The {@code /rules} directory's name isn't
 * passed, because its name might have changed. The same usage does apply for the
 * {@code /resource} directory.
 * 
 * @see ResourceDataBroker
 * @author PAX
 * @since 1.0.1
 */
public class DefaultResourceDataBroker implements ResourceDataBroker {

	/**
	 * The directory's name of the grammar checker's resource directory. The
	 * default value equals {@link ResourceDataBroker#RESOURCE_DIR}.
	 */
	protected String resourceDir;

	/**
	 * The directory's name of the grammar checker's rules directory. The
	 * default value equals {@link ResourceDataBroker#RULES_DIR}.
	 */
	protected String rulesDir;

	/**
	 * Instantiates this data broker with the default resource directory names
	 * as specified in:
	 * 
	 * <ul>
	 * <li>{@link ResourceDataBroker#RESOURCE_DIR}</li>
	 * <li>{@link ResourceDataBroker#RULES_DIR}</li>
	 * </ul>
	 */
	public DefaultResourceDataBroker() {
		this(ResourceDataBroker.RESOURCE_DIR, ResourceDataBroker.RULES_DIR);
	}

	/**
	 * Instantiates this data broker with the passed resource directory names.
	 * 
	 * @param resourceDir
	 *            The directory's name of the grammar checker's resource
	 *            directory. The default value equals
	 *            {@link ResourceDataBroker#RESOURCE_DIR}.
	 * @param rulesDir
	 *            The directory's name of the grammar checker's rules directory.
	 *            The default value equals
	 *            {@link ResourceDataBroker#RULES_DIR}.
	 */
	public DefaultResourceDataBroker(final String resourceDir, final String rulesDir) {
		this.setResourceDir(resourceDir);
		this.setRulesDir(rulesDir);
	}

	/**
	 * See:
	 * {@link ResourceDataBroker#getFromResourceDirAsStream(java.lang.String)}
	 *
	 * @param path
	 *            The relative path to the item inside of the {@code /resource}
	 *            directory. Please start your path information with {@code /}
	 *            because it will be concatenated with the directory's name:
	 *            /resource<b>/yourpath</b>.
	 * @return An {@link InputStream} object to the requested item or {@code
	 *         null} if it wasn't found.
	 */
	@Override
	public InputStream getFromResourceDirAsStream(final String path) {
		final String completePath = this.getCompleteResourceUrl(path);
		return ResourceDataBroker.class.getResourceAsStream(completePath);
	}

	/**
	 * See:
	 * {@link ResourceDataBroker#getFromResourceDirAsUrl(java.lang.String)}
	 *
	 * @param path
	 *            The relative path to the item inside of the {@code /resource}
	 *            directory. Please start your path information with {@code /}
	 *            because it will be concatenated with the directory's name:
	 *            /resource<b>/yourpath</b>.
	 * @return An {@link URL} object to the requested item or {@code null} if it
	 *         wasn't found.
	 */
	@Override
	public URL getFromResourceDirAsUrl(final String path) {
		final String completePath = this.getCompleteResourceUrl(path);
		return getFixedJarURL(ResourceDataBroker.class.getResource(completePath));
	}

	/**
	 * Concatenates the passed resource path with the currently set {@code
	 * resource} directory path.
	 * 
	 * @param path
	 *            The relative path to a resource item inside of the {@code
	 *            resource} directory.
	 * @return The full relative path to the resource including the path to the
	 *         {@code resource} directory.
	 */
	private String getCompleteResourceUrl(final String path) {
		final StringBuffer completePath = new StringBuffer(this.getResourceDir());

		if (!this.getResourceDir().endsWith("/") && !(path.charAt(0)=='/')) {
			completePath.append('/');
		}

		if (this.getResourceDir().endsWith("/") && (path.charAt(0)=='/')
				&& path.length() > 1) {
			completePath.append(path.substring(1));
		} else {
			completePath.append(path);
		}

		return completePath.toString();
	}

	/**
	 * See:
	 * {@link ResourceDataBroker#getFromRulesDirAsStream(java.lang.String)}
	 *
	 * @param path
	 *            The relative path to the item inside of the {@code /rules}
	 *            directory. Please start your path information with {@code /}
	 *            because it will be concatenated with the directory's name:
	 *            /rules<b>/yourpath</b>.
	 * @return An {@link InputStream} object to the requested item or {@code
	 *         null} if it wasn't found.
	 */
	@Override
	public InputStream getFromRulesDirAsStream(final String path) {
		final StringBuffer completePath = this.getCompleteRulesUrl(path);
		return ResourceDataBroker.class.getResourceAsStream(completePath.toString());
	}

	/**
	 * See: {@link ResourceDataBroker#getFromRulesDirAsUrl(java.lang.String)}
	 *
	 * @param path
	 *            The relative path to the item inside of the {@code /rules}
	 *            directory. Please start your path information with {@code /}
	 *            because it will be concatenated with the directory's name:
	 *            /rules<b>/yourpath</b>.
	 * @return An {@link URL} object to the requested item or {@code null} if it
	 *         wasn't found.
	 */
	@Override
	public URL getFromRulesDirAsUrl(final String path) {
		final StringBuffer completePath = this.getCompleteRulesUrl(path);
		return getFixedJarURL(ResourceDataBroker.class.getResource(completePath.toString()));
	}

	/**
	 * Concatenates the passed resource path with the currently set {@code
	 * rules} directory path.
	 * 
	 * @param path
	 *            The relative path to a resource item inside of the {@code
	 *            rules} directory.
	 * @return The full relative path to the resource including the path to the
	 *         {@code rules} directory.
	 */
	private StringBuffer getCompleteRulesUrl(final String path) {
	    final StringBuffer completePath = new StringBuffer(this.getRulesDir());

		if (!this.getRulesDir().endsWith("/") && !(path.charAt(0)=='/')) {
			completePath.append('/');
		}

		if (this.getRulesDir().endsWith("/") && (path.charAt(0)=='/') && path.length() > 1) {
			completePath.append(path.substring(1));
		} else {
			completePath.append(path);
		}

		return completePath;
	}

	/**
	 * @return The directory's name of the grammar checker's resource directory.
	 *         The default value equals
	 *         {@link ResourceDataBroker#RESOURCE_DIR}.
	 */
	@Override
	public String getResourceDir() {
		return this.resourceDir;
	}

	/**
	 * @param resourceDir
	 *            The directory's name of the grammar checker's resource
	 *            directory. The default value was
	 *            {@link ResourceDataBroker#RESOURCE_DIR}. Please let this
	 *            string start with {@code '/'} and use this character as path
	 *            separator. Don't set this character to the string's end. Valid
	 *            example value: {@code /subdir/furtherdir/resourcedir}.
	 */
	@Override
	public void setResourceDir(final String resourceDir) {
		this.resourceDir = (resourceDir == null) ? "" : resourceDir;
	}

	/**
	 * @return The directory's name of the grammar checker's rules directory.
	 *         The default value equals {@link ResourceDataBroker#RULES_DIR}.
	 */
	@Override
	public String getRulesDir() {
		return this.rulesDir;
	}

	/**
	 * @param rulesDir
	 *            The directory's name of the grammar checker's rules directory.
	 *            The default value was {@link ResourceDataBroker#RULES_DIR}.
	 *            Please let this string start with {@code '/'} and use this
	 *            character as path separator. Don't set this character to the
	 *            string's end. Valid example value: {@code
	 *            /subdir/furtherdir/rulesdir}.
	 */
	@Override
	public void setRulesDir(final String rulesDir) {
		this.rulesDir = (rulesDir == null) ? "" : rulesDir;
	}

    /**
     * Fixes the getResource bug if you want to obtain any resource from a JAR file under Java
     * 1.5.0_16 Webstart. (Workaround by {@code mevanclark} from http://forums.sun.com)
     * 
     * @param url The {@link URL} to be fixed.
     * @return The fixed version if necessary.
     */
    private static URL getFixedJarURL(URL url) {
        if (url == null) {
            return url;
        }

        final String originalURLProtocol = url.getProtocol();
        if (!"jar".equalsIgnoreCase(originalURLProtocol)) {
            return url;
        }

        final String originalURLString = url.toString();
        final int bangSlashIndex = originalURLString.indexOf("!/");
        if (bangSlashIndex > -1) {
            return url;
        }

        final String originalURLPath = url.getPath();
        final URLConnection urlConnection;
        try {
            urlConnection = url.openConnection();
            if (urlConnection == null) {
                throw new IOException("urlConnection is null");
            }
        } catch (IOException e) {
            return url;
        }

        final Permission urlConnectionPermission;
        try {
            urlConnectionPermission = urlConnection.getPermission();
            if (urlConnectionPermission == null) {
                throw new IOException("urlConnectionPermission is null");
            }
        } catch (IOException e) {
            return url;
        }

        final String urlConnectionPermissionName = urlConnectionPermission.getName();
        if (urlConnectionPermissionName == null) {
            return url;
        }

        final File file = new File(urlConnectionPermissionName);
        if (!file.exists()) {
            return url;
        }

        try {
            final String newURLStr = "jar:" + file.toURI().toURL().toExternalForm() + "!/" + originalURLPath;
            url = new URL(newURLStr);
        } catch (MalformedURLException e) {
            return url;
        }

        return url;
    }

}