org.odftoolkit.odfdom.pkg.StreamHelper Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of odfdom-java Show documentation

ODFDOM is an OpenDocument Format (ODF) framework. Its purpose is to provide an easy common way to create, access and manipulate ODF files, without requiring detailed knowledge of the ODF specification. It is designed to provide the ODF developer community with an easy lightwork programming API portable to any object-oriented language. The current reference implementation is written in Java.

There is a newer version: 0.8.11-incubating

Show newest version

/************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 *
 * Copyright 2008, 2010 Oracle and/or its affiliates. All rights reserved.
 *
 * Use is subject to license terms.
 *
 * 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. You can also
 * obtain a copy of the License at http://odftoolkit.org/docs/license.txt
 *
 * 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.odftoolkit.odfdom.pkg;

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

/**
 * This class reads from an InputStream and writes to an OutputStream.
 * No streams will be closed - calling classes must do this.
 */
class StreamHelper {

    // 4096 is thought to be the minimum page size for most systems;
    // change this for optimization
    public static final int PAGE_SIZE = 4096;
    private InputStream in;
    private OutputStream out;
    private boolean mStreamed;

    /**
     * Read from the input stream and write to the output. This method
     * does not close any stream; calling methods must take care of that.
     * @throws IOException when io error happens
     */
    static void transformStream(InputStream in, OutputStream out) throws IOException {
        StreamHelper s = new StreamHelper(in, out);
        s.stream();
    }

    /**
     * Create a new StreamHelper
     * @param in the input stream used for reading
     * @param out the output stream written to
     */
    StreamHelper(InputStream in, OutputStream out) {
        this.in = in;
        this.out = out;
        mStreamed = false;
    }

    /**
     * Read from the input stream and write to the output. This method can only
     * be called once. A second call will result in an IOException. This method
     * does not close any stream; calling methods must take care of that.
     * @throws IOException when io error happens
     */
    void stream() throws IOException {
        if (mStreamed) throw new IOException();
        byte[] buf = new byte[PAGE_SIZE];
        int r = 0;
        // let npe happen if one of the streams is null
        while ((r = in.read(buf, 0, PAGE_SIZE)) > -1) {
            out.write(buf, 0, r);
        }
        // free the references
        in = null;
        out = null;
        mStreamed = true;
    }
}