org.sourcepit.common.utils.io.UnclosableInputStream.java Source code

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Here is the source code for org.sourcepit.common.utils.io.UnclosableInputStream.java

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/*
 * Copyright 2014 Bernd Vogt and others.
 * 
 * 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 org.sourcepit.common.utils.io;

import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.io.IOUtils;

public abstract class UnclosableInputStream extends InputStream {
    private InputStream delegate;

    private boolean closed;

    public static UnclosableInputStream wrap(final InputStream inputStream) {
        return new UnclosableInputStream() {
            @Override
            protected InputStream openInputStream() throws IOException {
                return inputStream;
            }
        };
    }

    @Override
    public int read() throws IOException {
        if (closed) {
            throw new IOException("Stream already closed.");
        }
        if (delegate == null) {
            delegate = openInputStream();
        }
        return delegate.read();
    }

    protected abstract InputStream openInputStream() throws IOException;

    public void closeDelegate() {
        closed = true;
        IOUtils.closeQuietly(delegate);
        delegate = null;
    }
}