/*
 * Copyright (c) 2002-2012 Alibaba Group Holding Limited.
 * All rights reserved.
 *
 * 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.citrus.service.resource.support;

import static com.alibaba.citrus.util.Assert.*;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import com.alibaba.citrus.service.resource.Resource;

/**
 * 代表一个<code>InputStream</code>的资源。
 *
 * @author Michael Zhou
 */
public class InputStreamResource implements Resource {
    private final InputStream stream;

    /** 创建一个<code>InputStreamResource</code>。 */
    public InputStreamResource(InputStream stream) {
        this.stream = assertNotNull(stream, "stream");
    }

    /** 取得资源的<code>URL</code>。 */
    public URL getURL() {
        return null;
    }

    /** 取得资源的<code>File</code>。 */
    public File getFile() {
        return null;
    }

    /** 取得资源的<code>InputStream</code>。 */
    public InputStream getInputStream() throws IOException {
        return stream;
    }

    /** 判断资源是否存在。 */
    public boolean exists() {
        return stream != null;
    }

    /** 取得资源最近修改时间。 */
    public long lastModified() {
        return 0;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (stream == null ? 0 : stream.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null) {
            return false;
        }

        if (getClass() != obj.getClass()) {
            return false;
        }

        InputStreamResource other = (InputStreamResource) obj;

        if (stream == null) {
            if (other.stream != null) {
                return false;
            }
        } else if (!stream.equals(other.stream)) {
            return false;
        }

        return true;
    }

    /** 将resource转换成字符串表示。 */
    @Override
    public String toString() {
        StringBuilder buf = new StringBuilder();

        buf.append(getClass().getSimpleName()).append("[InputStream: ");
        buf.append(stream);
        buf.append("]");

        return buf.toString();
    }
}