/*
    * Copyright 2004-2008 the Seasar Foundation and the Others.
    *
    * 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 org.seasar.uruma.component.factory.desc;
  
  import java.io.InputStream;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.xml.XMLConstants;
  import javax.xml.parsers.SAXParser;
  import javax.xml.parsers.SAXParserFactory;
  import javax.xml.transform.stream.StreamSource;
  import javax.xml.validation.Schema;
  import javax.xml.validation.SchemaFactory;
  
  import org.seasar.framework.container.factory.ClassPathResourceResolver;
  import org.seasar.framework.exception.ResourceNotFoundRuntimeException;
  import org.seasar.framework.exception.SAXRuntimeException;
  import org.seasar.framework.util.InputStreamUtil;
  import org.seasar.framework.util.OgnlUtil;
  import org.seasar.framework.util.SAXParserFactoryUtil;
  import org.seasar.framework.xml.SaxHandler;
  import org.seasar.framework.xml.SaxHandlerParser;
  import org.seasar.uruma.component.factory.desc.handler.UcdTagHandlerRule;
  import org.seasar.uruma.core.UrumaConstants;
  import org.seasar.uruma.util.AssertionUtil;
  import org.seasar.uruma.util.resource.ResourceHandler;
  import org.seasar.uruma.util.resource.ResourceTraverser;
  import org.seasar.uruma.util.resource.ResourceTraverserFactory;
  import org.seasar.uruma.util.resource.impl.ExtResourceFilter;
  import org.xml.sax.SAXException;
  
  /**
   * @author y-komori
   */
  public class ComponentRegistry implements ResourceHandler {
      protected ClassPathResourceResolver resolver = new ClassPathResourceResolver();
  
      private List<UrumaComponentDesc> descs = new ArrayList<UrumaComponentDesc>();
  
      /**
       * 
       */
      public void registComponents() {
          registComponents(Thread.currentThread().getContextClassLoader());
      }
  
      /**
       * @param loader
       */
      public void registComponents(final ClassLoader loader) {
          URL root = loader.getResource("");
          URL origin = loader.getResource("components");
          ResourceTraverser traverser = ResourceTraverserFactory
                  .getResourceTraverser(origin);
          ExtResourceFilter filter = new ExtResourceFilter("ucd");
          traverser.traverse(root, origin, this, filter);
      }
  
      /*
       * @see
       * org.seasar.uruma.util.resource.ResourceHandler#handle(java.lang.String,
       * java.lang.String, java.io.InputStream)
       */
      public void handle(final String rootPath, final String path,
              final InputStream is) {
          System.err.println(path + " から読み込みます");
          UrumaComponentDesc desc = load(path);
          registComponent(desc);
          System.err.println(desc);
      }
  
      /**
       * コンポーネント・ディスクリプタを登録します。<br />
       * 
       * @param desc
       *            {@link UrumaComponentDesc} オブジェクト
       */
      public void registComponent(final UrumaComponentDesc desc) {
          AssertionUtil.assertNotNull("desc", desc);
          descs.add(desc);
      }
  
      /**
       * 指定されたパスから Uruma コンポーネントディスクリプタを読み込みます。<br />
      * 
      * @param path
      *            コンポーネントディスクリプタファイルのパス
      * @return {@link UrumaComponentDesc} オブジェクト
      */
     public UrumaComponentDesc load(final String path) {
         final SaxHandlerParser parser = createSaxHandlerParser(path);
         final InputStream is = getInputStream(path);
         try {
             UrumaComponentDesc desc = (UrumaComponentDesc) parser.parse(is,
                     path);
             return desc;
         } finally {
             InputStreamUtil.close(is);
         }
     }
 
     protected SaxHandlerParser createSaxHandlerParser(final String path) {
         System.setProperty("javax.xml.parsers.SAXParserFactory",
                 "com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl");
         final SAXParserFactory factory = SAXParserFactoryUtil.newInstance();
         factory.setNamespaceAware(true);
 
         final SchemaFactory schemaFactory = SchemaFactory
                 .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
         InputStream is = getInputStream(UrumaConstants.COMPONENT_DESC_SCHEMA_PATH);
         try {
             final Schema schema = schemaFactory.newSchema(new StreamSource(is));
             factory.setSchema(schema);
         } catch (SAXException ex) {
             throw new SAXRuntimeException(ex);
         } finally {
             InputStreamUtil.close(is);
         }
 
         final SAXParser saxParser = SAXParserFactoryUtil.newSAXParser(factory);
         final SaxHandler handler = createSaxHandler();
 
         return new SaxHandlerParser(handler, saxParser);
     }
 
     protected InputStream getInputStream(final String path) {
         final InputStream is = resolver.getInputStream(path);
 
         if (is == null) {
             throw new ResourceNotFoundRuntimeException(path);
         }
         return is;
     }
 
     protected SaxHandler createSaxHandler() {
         SaxHandler handler = new SaxHandler(new UcdTagHandlerRule());
         return handler;
     }
 
     protected void setupComponents() {
 
     }
 
     protected Object[] evaluateArgs(final List<String> argExprs) {
         int size = argExprs.size();
         Object[] args = new Object[size];
         for (int i = 0; i < size; i++) {
             Object exp = OgnlUtil.parseExpression(argExprs.get(i));
             args[i] = OgnlUtil.getValue(exp, null);
         }
         return args;
     }
 }