net.hasor.cobble.io.input.ClosedReader Maven / Gradle / Ivy

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 net.hasor.cobble.io.input;
import java.io.IOException;
import java.io.Reader;

/**
 * Closed reader. This reader returns -1 to all attempts to read something from the reader.
 * 
 * Typically uses of this class include testing for corner cases in methods
 * that accept input streams and acting as a sentinel value instead of a
 * {@code null} reader.
 *
 * @author 赵永春 ([email protected])
 */
public class ClosedReader extends Reader {
    /**
     * A singleton.
     */
    public static final ClosedReader CLOSED_READER_STREAM = new ClosedReader();

    /**
     * Returns -1 to indicate that the stream is closed.
     * @return always -1
     */
    @Override
    public int read() {
        return -1;
    }

    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        return -1;
    }

    @Override
    public void close() throws IOException {

    }
}