/**
 * Copyright (C) 2006 Google Inc.
 *
 * <p>
 * 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
 * </p>
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>
 * 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.
 * </p>
 */

package com.opensymphony.xwork2.inject;

/**
 * Dependency mapping key. Uniquely identified by the required type and name.
 *
 * @author crazybob@google.com (Bob Lee)
 */
class Key<T> {

    final Class<T> type;
    final String name;
    final int hashCode;

    private Key(Class<T> type, String name) {
        if (type == null) {
            throw new NullPointerException("Type is null.");
        }
        if (name == null) {
            throw new NullPointerException("Name is null.");
        }

        this.type = type;
        this.name = name;

        hashCode = type.hashCode() * 31 + name.hashCode();
    }

    Class<T> getType() {
        return type;
    }

    String getName() {
        return name;
    }

    @Override
    public int hashCode() {
        return hashCode;
    }

    @Override
    public boolean equals(Object o) {
        if (!(o instanceof Key)) {
            return false;
        }
        if (o == this) {
            return true;
        }
        Key other = (Key) o;
        return name.equals(other.name) && type.equals(other.type);
    }

    @Override
    public String toString() {
        return "[type=" + type.getName() + ", name='" + name + "']";
    }

    static <T> Key<T> newInstance(Class<T> type, String name) {
        return new Key<T>(type, name);
    }
}