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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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 com.rapiddweller.common.bean;

import com.rapiddweller.common.BeanUtil;
import com.rapiddweller.common.ConfigurationError;
import com.rapiddweller.common.StringUtil;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Provides classes by name, supporting package import and local class names.
 * Created at 15.11.2008 17:03:04
 *
 * @author Volker Bergmann
 * @since 0.4.6
 */
public class ClassCache {

  private static final Logger LOGGER = LogManager.getLogger(ClassCache.class);

  private final Map> classes;
  private final List packages;
  private final Set nonClassNames = new HashSet<>(1000);

  /**
   * Instantiates a new Class cache.
   */
  public ClassCache() {
    classes = new HashMap<>();
    packages = new ArrayList<>();
    importPackage("java.lang");
  }

  /**
   * Import class.
   *
   * @param className the class name
   */
  public void importClass(String className) {
    className = className.trim();
    if (className.endsWith(".*")) {
      importPackage(className.substring(0, className.length() - 2));
    } else {
      classes.put(StringUtil.lastToken(className, '.'), BeanUtil.forName(className));
    }
  }

  /**
   * Import package.
   *
   * @param packageName the package name
   */
  public void importPackage(String packageName) {
    packages.add(packageName);
  }

  /**
   * For name class.
   *
   * @param name the name
   * @return the class
   */
  public Class forName(String name) {
    Class result = classes.get(name);
    if (result != null) {
      return result;
    }
    if (!nonClassNames.contains(name)) {
      try {
        result = BeanUtil.forName(name);
        classes.put(result.getSimpleName(), result);
        return result;
      } catch (ConfigurationError e) {
        nonClassNames.add(name);
        LOGGER.debug("class not found: {}", name);
      }
    }
    for (String pkg : packages) {
      String fqnTrial = pkg + '.' + name;
      if (!nonClassNames.contains(fqnTrial)) {
        try {
          result = BeanUtil.forName(fqnTrial);
          classes.put(result.getSimpleName(), result);
          return result;
        } catch (ConfigurationError e) {
          nonClassNames.add(fqnTrial);
          LOGGER.debug("class not found: {}", name);
        }
      }
    }
    throw new ConfigurationError("Class not found: " + name);
  }
}