package com.tfltravelalerts.common.persistence;

/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.
 */

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;

/**
 * An immutable implementation of the {@link ParameterizedType} interface. This
 * object allows us to build a reflective {@link Type} objects on demand. This
 * object is used to support serialization and deserialization of classes with
 * an {@code ParameterizedType} field where as least one of the actual type
 * parameters is a {@code TypeVariable}.
 * <p>
 * Here's an example class:
 * 
 * <pre>
 * class Foo<T> {
 *     private List<T> someList;
 * 
 *     Foo(List<T> list) {
 *         this.someList = list;
 *     }
 * }
 * </pre>
 * 
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
final class ParameterizedTypeImpl implements ParameterizedType {

    private final Type rawType;
    private final Type[] actualTypeArguments;
    private final Type owner;

    public ParameterizedTypeImpl(Type rawType, Type[] actualTypeArguments, Type owner) {
        this.rawType = rawType;
        this.actualTypeArguments = actualTypeArguments;
        this.owner = owner;
    }

    public Type getRawType() {
        return rawType;
    }

    public Type[] getActualTypeArguments() {
        return actualTypeArguments;
    }

    public Type getOwnerType() {
        return owner;
    }

    @Override
    public boolean equals(Object o) {
        if (!(o instanceof ParameterizedType)) {
            return false;
        }
        // Check that information is equivalent
        ParameterizedType that = (ParameterizedType) o;
        if (this == that) {
            return true;
        }
        Type thatOwner = that.getOwnerType();
        Type thatRawType = that.getRawType();

        return (owner == null ? thatOwner == null : owner.equals(thatOwner))
                && (rawType == null ? thatRawType == null : rawType.equals(thatRawType))
                && Arrays.equals(actualTypeArguments, that.getActualTypeArguments());
    }

    @Override
    public int hashCode() {
        return Arrays.hashCode(actualTypeArguments)
                ^ (owner == null ? 0 : owner.hashCode())
                ^ (rawType == null ? 0 : rawType.hashCode());
    }
}