116 lines
3.8 KiB
Java
116 lines
3.8 KiB
Java
/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.hssf.record.aggregates;
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import org.apache.poi.hssf.record.Record;
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import org.apache.poi.hssf.record.RecordBase;
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/**
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* <tt>RecordAggregate</tt>s are groups of of BIFF <tt>Record</tt>s that are typically stored
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* together and/or updated together. Workbook / Sheet records are typically stored in a sequential
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* list, which does not provide much structure to coordinate updates.
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*
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* @author Josh Micich
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*/
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public abstract class RecordAggregate extends RecordBase {
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/**
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* Visit each of the atomic BIFF records contained in this {@link RecordAggregate} in the order
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* that they should be written to file. Implementors may or may not return the actual
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* {@link Record}s being used to manage POI's internal implementation. Callers should not
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* assume either way, and therefore only attempt to modify those {@link Record}s after cloning
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*/
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public abstract void visitContainedRecords(RecordVisitor rv);
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public final int serialize(int offset, byte[] data) {
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SerializingRecordVisitor srv = new SerializingRecordVisitor(data, offset);
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visitContainedRecords(srv);
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return srv.countBytesWritten();
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}
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public int getRecordSize() {
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RecordSizingVisitor rsv = new RecordSizingVisitor();
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visitContainedRecords(rsv);
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return rsv.getTotalSize();
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}
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public interface RecordVisitor {
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/**
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* Implementors may call non-mutating methods on Record r.
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* @param r must not be <code>null</code>
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*/
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void visitRecord(Record r);
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}
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private static final class SerializingRecordVisitor implements RecordVisitor {
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private final byte[] _data;
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private final int _startOffset;
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private int _countBytesWritten;
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public SerializingRecordVisitor(byte[] data, int startOffset) {
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_data = data;
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_startOffset = startOffset;
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_countBytesWritten = 0;
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}
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public int countBytesWritten() {
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return _countBytesWritten;
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}
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public void visitRecord(Record r) {
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int currentOffset = _startOffset + _countBytesWritten;
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_countBytesWritten += r.serialize(currentOffset, _data);
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}
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}
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private static final class RecordSizingVisitor implements RecordVisitor {
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private int _totalSize;
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public RecordSizingVisitor() {
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_totalSize = 0;
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}
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public int getTotalSize() {
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return _totalSize;
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}
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public void visitRecord(Record r) {
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_totalSize += r.getRecordSize();
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}
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}
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/**
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* A wrapper for {@link RecordVisitor} which accumulates the sizes of all
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* records visited.
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*/
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public static final class PositionTrackingVisitor implements RecordVisitor {
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private final RecordVisitor _rv;
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private int _position;
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public PositionTrackingVisitor(RecordVisitor rv, int initialPosition) {
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_rv = rv;
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_position = initialPosition;
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}
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public void visitRecord(Record r) {
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_position += r.getRecordSize();
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_rv.visitRecord(r);
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}
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public void setPosition(int position) {
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_position = position;
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}
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public int getPosition() {
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return _position;
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}
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}
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}
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