framework/src/main/java/org/checkerframework/framework/util/AnnotationMirrorMap.java

package org.checkerframework.framework.util;

import java.util.Collection;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import javax.lang.model.element.AnnotationMirror;
import org.checkerframework.javacutil.AnnotationUtils;

/**
 * The Map interface defines some of its methods with respect to the equals method. This
 * implementation of Map violates those specifications, but fulfills the same property using {@link
 * AnnotationUtils#areSame}.
 *
 * <p>For example, the specification for the containsKey(Object key) method says: "returns true if
 * and only if this map contains a mapping for a key k such that (key == null ? k == null :
 * key.equals(k))." The specification for {@link AnnotationMirrorMap#containsKey} is "returns true
 * if and only if this map contains a mapping for a key k such that (key == null ? k == null :
 * AnnotationUtils.areSame(key, k))."
 *
 * <p>AnnotationMirror is an interface and not all implementing classes provide a correct equals
 * method; therefore, existing implementations of Map cannot be used.
 */
public class AnnotationMirrorMap<V> implements Map<AnnotationMirror, V> {

  /** The actual map to which all work is delegated. */
  private final Map<AnnotationMirror, V> shadowMap;

  /** Default constructor. */
  public AnnotationMirrorMap() {
    this.shadowMap = new TreeMap<>(AnnotationUtils::compareAnnotationMirrors);
  }

  /**
   * Creates an annotation mirror map and adds all the mappings in {@code copy}.
   *
   * @param copy a map whose contents should be copied to the newly created map
   */
  public AnnotationMirrorMap(Map<AnnotationMirror, ? extends V> copy) {
    this();
    this.putAll(copy);
  }

  @Override
  public int size() {
    return shadowMap.size();
  }

  @Override
  public boolean isEmpty() {
    return shadowMap.isEmpty();
  }

  @Override
  public boolean containsKey(Object key) {
    if (key instanceof AnnotationMirror) {
      return AnnotationUtils.containsSame(shadowMap.keySet(), (AnnotationMirror) key);
    } else {
      return false;
    }
  }

  @Override
  public boolean containsValue(Object value) {
    return shadowMap.containsValue(value);
  }

  @Override
  public V get(Object key) {
    if (key instanceof AnnotationMirror) {
      AnnotationMirror keyAnno =
          AnnotationUtils.getSame(shadowMap.keySet(), (AnnotationMirror) key);
      if (keyAnno != null) {
        return shadowMap.get(keyAnno);
      }
    }
    return null;
  }

  @Override
  public V put(AnnotationMirror key, V value) {
    V pre = get(key);
    remove(key);
    shadowMap.put(key, value);
    return pre;
  }

  @Override
  public V remove(Object key) {
    if (key instanceof AnnotationMirror) {
      AnnotationMirror keyAnno =
          AnnotationUtils.getSame(shadowMap.keySet(), (AnnotationMirror) key);
      if (keyAnno != null) {
        return shadowMap.remove(keyAnno);
      }
    }
    return null;
  }

  @Override
  public void putAll(Map<? extends AnnotationMirror, ? extends V> m) {
    for (Map.Entry<? extends AnnotationMirror, ? extends V> entry : m.entrySet()) {
      put(entry.getKey(), entry.getValue());
    }
  }

  @Override
  public void clear() {
    shadowMap.clear();
  }

  @Override
  public Set<AnnotationMirror> keySet() {
    return new AnnotationMirrorSet(shadowMap.keySet());
  }

  @Override
  public Collection<V> values() {
    return shadowMap.values();
  }

  @Override
  public Set<Map.Entry<AnnotationMirror, V>> entrySet() {
    return shadowMap.entrySet();
  }

  @Override
  public String toString() {
    return shadowMap.toString();
  }
}