001: /*
002: * Copyright (c) 2007, intarsys consulting GmbH
003: *
004: * Redistribution and use in source and binary forms, with or without
005: * modification, are permitted provided that the following conditions are met:
006: *
007: * - Redistributions of source code must retain the above copyright notice,
008: * this list of conditions and the following disclaimer.
009: *
010: * - Redistributions in binary form must reproduce the above copyright notice,
011: * this list of conditions and the following disclaimer in the documentation
012: * and/or other materials provided with the distribution.
013: *
014: * - Neither the name of intarsys nor the names of its contributors may be used
015: * to endorse or promote products derived from this software without specific
016: * prior written permission.
017: *
018: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
019: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
020: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
021: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
022: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
023: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
024: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
025: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
026: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
027: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
028: * POSSIBILITY OF SUCH DAMAGE.
029: */
030: package de.intarsys.pdf.st;
031:
032: import java.io.IOException;
033:
034: import de.intarsys.pdf.cos.COSObject;
035: import de.intarsys.pdf.cos.COSObjectKey;
036: import de.intarsys.pdf.crypt.ISystemSecurityHandler;
037: import de.intarsys.pdf.parser.COSLoadException;
038:
039: /**
040: * Abstract superclass for a XRef entry.
041: * <p>
042: * The XRef entry describes an object slot in a XRef. The entry consists of an
043: * offset in the file, a generation number and a token indicating if this entry
044: * is free.
045: */
046: public abstract class STXRefEntry implements Comparable {
047: /** The generation number of the entry */
048: private COSObjectKey key;
049:
050: /**
051: * Create XRefEntry
052: *
053: * @param index
054: *
055: * @param generation
056: *
057: */
058: protected STXRefEntry(COSObjectKey key) {
059: this .key = key;
060: }
061:
062: abstract public boolean isFree();
063:
064: public int getGenerationNumber() {
065: return getKey().getGenerationNumber();
066: }
067:
068: public int compareTo(Object obj) {
069: if (obj instanceof STXRefEntry) {
070: return (getObjectNumber() - ((STXRefEntry) obj)
071: .getObjectNumber());
072: }
073: return -1;
074: }
075:
076: public abstract STXRefEntryOccupied fill(int pos);
077:
078: abstract protected void unlink();
079:
080: public int getObjectNumber() {
081: return getKey().getObjectNumber();
082: }
083:
084: public String toString() {
085: return getKey().toString();
086: }
087:
088: public abstract COSObject load(STDocument doc,
089: ISystemSecurityHandler securityHandler) throws IOException,
090: COSLoadException;
091:
092: public abstract long getColumn1();
093:
094: public abstract int getColumn2();
095:
096: public COSObjectKey getKey() {
097: return key;
098: }
099:
100: public abstract void accept(IXRefEntryVisitor visitor)
101: throws XRefEntryVisitorException;
102:
103: public abstract STXRefEntry copy();
104: }
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