/*
 * 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.
 */

/* $Id: ObjectStreamManager.java 1305467 2012-03-26 17:39:20Z vhennebert $ */

package org.apache.fop.pdf;

import java.util.ArrayList;
import java.util.List;

import org.apache.fop.pdf.xref.CompressedObjectReference;

Manages a collection of object streams, creating new streams as necessary to keep the
number of objects in each stream at the recommended value. Streams are related to each
other through the use of the Extends entry in the stream dictionary.
/**
 * Manages a collection of object streams, creating new streams as necessary to keep the
 * number of objects in each stream at the recommended value. Streams are related to each
 * other through the use of the Extends entry in the stream dictionary.
 */
class ObjectStreamManager {

    private static final int OBJECT_STREAM_CAPACITY = 100;

    private final PDFDocument pdfDocument;

    private final List<CompressedObjectReference> compressedObjectReferences;

    private int numObjectsInStream;

    private ObjectStream currentObjectStream;

    ObjectStreamManager(PDFDocument pdfDocument) {
        this.pdfDocument = pdfDocument;
        createObjectStream();
        compressedObjectReferences = new ArrayList<CompressedObjectReference>();
    }

    void add(CompressedObject compressedObject) {
        if (numObjectsInStream++ == OBJECT_STREAM_CAPACITY) {
            createObjectStream();
            numObjectsInStream = 1;
        }
        compressedObjectReferences.add(currentObjectStream.addObject(compressedObject));
    }

    private void createObjectStream() {
        currentObjectStream = currentObjectStream == null
                ? new ObjectStream()
                : new ObjectStream(currentObjectStream);
        pdfDocument.assignObjectNumber(currentObjectStream);
        pdfDocument.addTrailerObject(currentObjectStream);
    }

    List<CompressedObjectReference> getCompressedObjectReferences() {
        return compressedObjectReferences;
    }
}