Druid/src/main/java/com/alibaba/druid/proxy/jdbc/WrapperProxyImpl.java

/*
 * Copyright 1999-2011 Alibaba Group Holding Ltd.
 *
 * 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 com.alibaba.druid.proxy.jdbc;

import java.sql.SQLException;
import java.sql.Wrapper;
import java.util.HashMap;
import java.util.Map;

import com.alibaba.druid.filter.FilterChain;

/**
 * @author wenshao<szujobs@hotmail.com>
 */
public abstract class WrapperProxyImpl implements WrapperProxy {

    private final Wrapper             raw;

    private final long                id;

    private final Map<String, Object> attributes = new HashMap<String, Object>(4); // 不需要线程安全

    public WrapperProxyImpl(Wrapper wrapper, long id){
        this.raw = wrapper;
        this.id = id;
    }

    public long getId() {
        return this.id;
    }

    public Object getRawObject() {
        return raw;
    }

    public abstract FilterChain createChain();

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        if (iface == null) {
            return false;
        }

        if (iface.isInstance(this)) {
            return true;
        }

        return createChain().isWrapperFor(raw, iface);
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        if (iface == null) {
            return null;
        }

        if (iface.isInstance(this)) {
            return (T) this;
        }

        return createChain().unwrap(raw, iface);
    }

    public Map<String, Object> getAttributes() {
        return this.attributes;
    }

}