GenericProperty.java

/**
 * Copyright (c) 2008, SnakeYAML
 *
 * 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 org.yaml.snakeyaml.introspector;

import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/**
 * Shared code for all the properties
 */
public abstract class GenericProperty extends Property {

  private final Type genType;

  public GenericProperty(String name, Class<?> aClass, Type aType) {
    super(name, aClass);
    genType = aType;
    actualClassesChecked = aType == null;
  }

  private boolean actualClassesChecked;
  private Class<?>[] actualClasses;

  public Class<?>[] getActualTypeArguments() { // should we synchronize here ?
    if (!actualClassesChecked) {
      if (genType instanceof ParameterizedType) {
        ParameterizedType parameterizedType = (ParameterizedType) genType;
        Type[] actualTypeArguments = parameterizedType.getActualTypeArguments();
        if (actualTypeArguments.length > 0) {
          actualClasses = new Class<?>[actualTypeArguments.length];
          for (int i = 0; i < actualTypeArguments.length; i++) {
            if (actualTypeArguments[i] instanceof Class<?>) {
              actualClasses[i] = (Class<?>) actualTypeArguments[i];
            } else if (actualTypeArguments[i] instanceof ParameterizedType) {
              actualClasses[i] =
                  (Class<?>) ((ParameterizedType) actualTypeArguments[i]).getRawType();
            } else if (actualTypeArguments[i] instanceof GenericArrayType) {
              Type componentType =
                  ((GenericArrayType) actualTypeArguments[i]).getGenericComponentType();
              if (componentType instanceof Class<?>) {
                actualClasses[i] = Array.newInstance((Class<?>) componentType, 0).getClass();
              } else {
                actualClasses = null;
                break;
              }
            } else {
              actualClasses = null;
              break;
            }
          }
        }
      } else if (genType instanceof GenericArrayType) {
        Type componentType = ((GenericArrayType) genType).getGenericComponentType();
        if (componentType instanceof Class<?>) {
          actualClasses = new Class<?>[] {(Class<?>) componentType};
        }
      } else if (genType instanceof Class<?>) {// XXX this check is only
        // required for IcedTea6
        Class<?> classType = (Class<?>) genType;
        if (classType.isArray()) {
          actualClasses = new Class<?>[1];
          actualClasses[0] = getType().getComponentType();
        }
      }
      actualClassesChecked = true;
    }
    return actualClasses;
  }
}