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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.

There is a newer version: 9.1.6

/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2021 Guardsquare NV
 *
 * 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 proguard.classfile;

import static proguard.classfile.util.ClassUtil.externalClassName;

import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Map;

/**
 * Represents the signature of a class without any member information.
 *
 * @author Samuel Hopstock
 */
public class ClassSignature extends Signature {

  private static final Map signatureCache =
      Collections.synchronizedMap(new IdentityHashMap<>());

  public ClassSignature(String className) {
    super(className, className.hashCode());
  }

  public ClassSignature(Clazz clazz) {
    this(clazz.getName());
  }

  @Override
  public boolean isIncomplete() {
    return className == null;
  }

  @Override
  protected String calculateFqn() {
    return className;
  }

  @Override
  protected String calculatePrettyFqn() {
    return externalClassName(className);
  }

  /**
   * Remove all currently cached {@link ClassSignature} objects from the cache, allowing them to be
   * removed by the garbage collector.
   */
  public static void clearCache() {
    signatureCache.clear();
  }

  /**
   * Get the singleton {@link ClassSignature} object for this specific {@link Clazz}. If it is not
   * yet available in the cache, it will be newly instantiated.
   *
   * @param clazz The class containing the target field
   * @return The cached or newly generated {@link ClassSignature} object
   */
  public static ClassSignature computeIfAbsent(Clazz clazz) {
    return signatureCache.computeIfAbsent(clazz, c -> new ClassSignature(c.getName()));
  }
}