////////////////////////////////////////////////////////////////////////////////

 // checkstyle: Checks Java source code for adherence to a set of rules.

 // Copyright (C) 2001-2014  Oliver Burn

 //

 // 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 ////////////////////////////////////////////////////////////////////////////////

 package com.puppycrawl.tools.checkstyle.checks.imports;

 import com.puppycrawl.tools.checkstyle.api.AbstractLoader;

 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;

 import com.puppycrawl.tools.checkstyle.api.FastStack;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.MalformedURLException;

 import java.net.URI;

 import java.util.HashMap;

 import java.util.Map;

 import javax.xml.parsers.ParserConfigurationException;

 import org.xml.sax.Attributes;

 import org.xml.sax.InputSource;

 import org.xml.sax.SAXException;

 /**

  * Responsible for loading the contents of an import control configuration file.

  * @author Oliver Burn

  */

 final class ImportControlLoader extends AbstractLoader

 {

     /** the public ID for the configuration dtd */

     private static final String DTD_PUBLIC_ID_1_0 =

         "-//Puppy Crawl//DTD Import Control 1.0//EN";

     /** the public ID for the configuration dtd */

     private static final String DTD_PUBLIC_ID_1_1 =

         "-//Puppy Crawl//DTD Import Control 1.1//EN";

     /** the resource for the configuration dtd */

     private static final String DTD_RESOURCE_NAME_1_0 =

         "com/puppycrawl/tools/checkstyle/checks/imports/import_control_1_0.dtd";

     /** the resource for the configuration dtd */

     private static final String DTD_RESOURCE_NAME_1_1 =

         "com/puppycrawl/tools/checkstyle/checks/imports/import_control_1_1.dtd";

     /** Used to hold the {@link PkgControl} objects. */

     private final FastStack<PkgControl> mStack = FastStack.newInstance();

     /** the map to lookup the resource name by the id */

     private static final Map<String, String> DTD_RESOURCE_BY_ID =

         new HashMap<String, String>();

     /** Initialise the map */

     static {

         DTD_RESOURCE_BY_ID.put(DTD_PUBLIC_ID_1_0, DTD_RESOURCE_NAME_1_0);

         DTD_RESOURCE_BY_ID.put(DTD_PUBLIC_ID_1_1, DTD_RESOURCE_NAME_1_1);

     }

     /**

      * Constructs an instance.

      * @throws ParserConfigurationException if an error occurs.

      * @throws SAXException if an error occurs.

      */

     private ImportControlLoader() throws ParserConfigurationException,

             SAXException

     {

         super(DTD_RESOURCE_BY_ID);

     }

     @Override

     public void startElement(final String aNamespaceURI,

                              final String aLocalName,

                              final String aQName,

                              final Attributes aAtts)

         throws SAXException

     {

         if ("import-control".equals(aQName)) {

             final String pkg = safeGet(aAtts, "pkg");

             mStack.push(new PkgControl(pkg));

         }

         else if ("subpackage".equals(aQName)) {

             assert !mStack.isEmpty();

             final String name = safeGet(aAtts, "name");

             mStack.push(new PkgControl(mStack.peek(), name));

         }

         else if ("allow".equals(aQName) || "disallow".equals(aQName)) {

             assert !mStack.isEmpty();

             // Need to handle either "pkg" or "class" attribute.

             // May have "exact-match" for "pkg"

             // May have "local-only"

             final boolean isAllow = "allow".equals(aQName);

             final boolean isLocalOnly = (aAtts.getValue("local-only") != null);

             final String pkg = aAtts.getValue("pkg");

             final boolean regex = (aAtts.getValue("regex") != null);

             final Guard g;

             if (pkg != null) {

                 final boolean exactMatch =

                     (aAtts.getValue("exact-match") != null);

                 g = new Guard(isAllow, isLocalOnly, pkg, exactMatch, regex);

             }

             else {

                 // handle class names which can be normal class names or regular

                 // expressions

                 final String clazz = safeGet(aAtts, "class");

                 g = new Guard(isAllow, isLocalOnly, clazz, regex);

             }

             final PkgControl pc = mStack.peek();

             pc.addGuard(g);

         }

     }

     @Override

     public void endElement(final String aNamespaceURI, final String aLocalName,

         final String aQName)

     {

         if ("subpackage".equals(aQName)) {

             assert mStack.size() > 1;

             mStack.pop();

         }

     }

     /**

      * Loads the import control file from a file.

      * @param aUri the uri of the file to load.

      * @return the root {@link PkgControl} object.

      * @throws CheckstyleException if an error occurs.

      */

     static PkgControl load(final URI aUri) throws CheckstyleException

     {

         InputStream is = null;

         try {

             is = aUri.toURL().openStream();

         }

         catch (final MalformedURLException e) {

             throw new CheckstyleException("syntax error in url " + aUri, e);

         }

         catch (final IOException e) {

             throw new CheckstyleException("unable to find " + aUri, e);

         }

         final InputSource source = new InputSource(is);

         return load(source, aUri);

     }

     /**

      * Loads the import control file from a {@link InputSource}.

      * @param aSource the source to load from.

      * @param aUri uri of the source being loaded.

      * @return the root {@link PkgControl} object.

      * @throws CheckstyleException if an error occurs.

      */

     private static PkgControl load(final InputSource aSource,

         final URI aUri) throws CheckstyleException

     {

         try {

             final ImportControlLoader loader = new ImportControlLoader();

             loader.parseInputSource(aSource);

             return loader.getRoot();

         }

         catch (final ParserConfigurationException e) {

             throw new CheckstyleException("unable to parse " + aUri, e);

         }

         catch (final SAXException e) {

             throw new CheckstyleException("unable to parse " + aUri

                     + " - " + e.getMessage(), e);

         }

         catch (final IOException e) {

             throw new CheckstyleException("unable to read " + aUri, e);

         }

     }

     /**

      * @return the root {@link PkgControl} object loaded.

      */

     private PkgControl getRoot()

     {

         assert mStack.size() == 1;

         return mStack.peek();

     }

     /**

      * Utility to safely get an attribute. If it does not exist an exception

      * is thrown.

      * @param aAtts collect to get attribute from.

      * @param aName name of the attribute to get.

      * @return the value of the attribute.

      * @throws SAXException if the attribute does not exist.

      */

     private String safeGet(final Attributes aAtts, final String aName)

         throws SAXException

     {

         final String retVal = aAtts.getValue(aName);

         if (retVal == null) {

             throw new SAXException("missing attribute " + aName);

         }

         return retVal;

     }

 }