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/*
 * Copyright (c) 2012 Google Inc.
 *
 * All rights reserved. This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at
 *
 * http://www.eclipse.org/legal/epl-v10.html
 */
package com.google.eclipse.xtext.filename.resource;

import static com.google.eclipse.xtext.filename.resource.URIs.isMyDslFile;
import static org.eclipse.emf.ecore.resource.ContentHandler.Validity.VALID;

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;

import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.resource.impl.ContentHandlerImpl;

/**
 * Object that provides content description for the input streams associated to URIs that refer to
 * "MyDsl" files.
 *
 * @author alruiz@google.com (Alex Ruiz)
 */
public class MyDslContentHandler extends ContentHandlerImpl {

  /** Content type for "MyDsl" files. */
  public static final String MY_DSL_FILE_CONTENT_TYPE = "com.google.eclipse.MyDsl";

  /**
   * Indicates that this content handler can only handle URIs that belong to a "MyDsl" files.
   * @param uri the URI to check. It may be {@code null}.
   * @return {@code true} if the given URI belongs to a "MyDsl" file; {@code false} otherwise.
   */
  @Override public boolean canHandle(URI uri) {
    return isMyDslFile(uri);
  }

  /**
   * Returns a map of properties that describe the content of the given URI's corresponding input
   * stream. If the given URI refers to a "MyDsl" file, this method will mark the contents as valid
   * and it will assign the content type appropiately.
   * @param uri the URI for which to determine the content description.
   * @param inputStream the {@code InputStream} associated with the given URI.
   * @param options direct what kind of description is needed.
   * @param context contextual information that content handlers use to store partially computed
   * results.
   * @return a map of properties that describe the content of the given URI's corresponding input
   * stream.
   * @throws IOException if there is a problem reading the stream.
   */
  @Override public Map<String, Object> contentDescription(URI uri, InputStream inputStream,
      Map<?, ?> options, Map<Object, Object> context) throws IOException {
    Map<String, Object> description = super.contentDescription(uri, inputStream, options, context);
    if (canHandle(uri)) {
      description.put(VALIDITY_PROPERTY, VALID);
      description.put(CONTENT_TYPE_PROPERTY, MY_DSL_FILE_CONTENT_TYPE);
    }
    return description;
  }
}