/*
 * Copyright 2000-2009 JetBrains s.r.o.
 *
 * 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.
 */

/*
 * Created by IntelliJ IDEA.
 * User: mike
 * Date: Jul 23, 2002
 * Time: 2:18:55 PM
 * To change template for new interface use 
 * Code Style | Class Templates options (Tools | IDE Options).
 */
package com.intellij.codeInsight.lookup;

import com.intellij.openapi.extensions.ExtensionPointName;
import org.jetbrains.annotations.Nullable;

public abstract class CharFilter {
  public static final ExtensionPointName<CharFilter> EP_NAME = ExtensionPointName.create("com.intellij.lookup.charFilter");

  public static enum Result {
    ADD_TO_PREFIX, SELECT_ITEM_AND_FINISH_LOOKUP, HIDE_LOOKUP
  }

  /**
   * Informs about further action on typing character c when completion lookup has specified prefix. If
   * @param c character being inserted
   * @param prefixLength
   * @param lookup
   * @return further action or null, which indicates that some other {@link com.intellij.codeInsight.lookup.CharFilter}
   * should handle this char. Default char filter handles common cases like finishing with ' ', '(', ';', etc.  
   */
  @Nullable
  public abstract Result acceptChar(char c, final int prefixLength, final Lookup lookup);
}