edu.harvard.hul.ois.jhove.module.pdf.PdfProfile Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of pdf-hul Show documentation
Show all versions of pdf-hul Show documentation
PDF module developed by Harvard University Library
/**********************************************************************
* Jhove - JSTOR/Harvard Object Validation Environment
* Copyright 2003 by JSTOR and the President and Fellows of Harvard College
**********************************************************************/
package edu.harvard.hul.ois.jhove.module.pdf;
import edu.harvard.hul.ois.jhove.module.*;
import java.io.*;
import java.util.*;
/**
* Abstract class for PDF profile checkers.
*/
public abstract class PdfProfile
{
/******************************************************************
* PRIVATE CLASS FIELDS.
******************************************************************/
/** The module invoking this profile. */
protected PdfModule _module;
/** A brief human-readable description of the profile. */
protected String _profileText;
/** The Parser being used on the file. */
protected Parser _parser;
/** The file being analyzed. */
protected RandomAccessFile _raf;
/** Set to true if this file has previously
* been validated by an invocation of this PdfProfile. */
private boolean _alreadyOK;
/**
* Creates a PdfProfile.
* Subclass constructors should call the super constructor,
* then assign a value to _profileText.
*
* @param module The PDFModule we're working under
*
*/
public PdfProfile (PdfModule module)
{
_module = module;
}
/**
* Returns the value of the alreadyOK flag.
* This flag when one profile depends on another, to save redundant
* checking.
* The alreadyOK flag is set whenever satisfiesProfile
* returns true.
*/
public boolean isAlreadyOK ()
{
return _alreadyOK;
}
/**
* Returns true if the document satisfies the profile.
* This calls satisfiesThisProfile(), which does the actual work.
*
* @param raf The RandomAccessFile being parsed
* @param parser The Parser being used on the file
*/
public final boolean satisfiesProfile
(RandomAccessFile raf, Parser parser)
{
_raf = raf;
_parser = parser;
_alreadyOK = false;
boolean sp = satisfiesThisProfile ();
if (sp) {
_alreadyOK = true;
}
return sp;
}
/**
* Returns true if the document satisfies the
* profile. Subclasses should override satisfiesThisProfile(),
* not satisfiesProfile(), as
* satisfiesProfile() does some
* additional bookkeeping for all subclases.
*/
public abstract boolean satisfiesThisProfile ();
/**
* Returns the text which describes this profile.
*/
public String getText ()
{
return _profileText;
}
/** Returns true if a Filter object contains a filter name which
* matches any of the Strings in the second argument.
* Will return false if a PdfException is thrown due
* to an unexpected data type.
*
* (Note 24-Feb-04: This was returning false if any filter matched,
* but that's contrary to both the sense conveyed by the name and
* the way it's being called. Was there a reason it was that way?)
*
* @param filter A PdfObject which may be either a PdfSimpleObject
* encapsulating a Name, or a PdfArray of such objects.
* If a null value is passed, it doesn't match any filter,
* so false is returned.
* @param names An array of Strings naming the filters which should
* precipitate a true result
*/
protected boolean hasFilters (PdfObject filter, String[] names)
{
String filterName;
try {
if (filter == null) {
return false;
}
if (filter instanceof PdfSimpleObject) {
// Name of just one filter
filterName = ((PdfSimpleObject) filter).getStringValue ();
for (int j = 0; j < names.length; j++) {
if (names[j].equals (filterName)) {
return true;
}
}
}
else {
// If it's not a name, it must be an array
Vector filterVec = ((PdfArray) filter).getContent ();
for (int i = 0; i < filterVec.size (); i++) {
PdfSimpleObject filt =
(PdfSimpleObject) filterVec.elementAt (i);
filterName = filt.getStringValue ();
for (int j = 0; j < names.length; j++) {
if (names[j].equals (filterName)) {
return true;
}
}
}
}
}
catch (Exception e) {
return false;
}
return false; // none of the filters were found
}
/**
* This checks the "XObjects" dictionary, which is a dictionary whose
* entries have values that are XObjects. Override xObjectOK to
* implement profile-specific behavior.
*/
protected boolean xObjectsOK (PdfDictionary xos)
{
if (xos == null) {
return true; // nothing to fail
}
try {
Iterator iter = xos.iterator ();
while (iter.hasNext ()) {
PdfObject obj = _module.resolveIndirectObject
(iter.next ());
if (obj instanceof PdfStream) {
obj = ((PdfStream) obj).getDict ();
}
if (obj instanceof PdfDictionary) {
PdfDictionary xobj = (PdfDictionary) obj;
if (!xObjectOK (xobj)) {
return false;
}
}
}
}
catch (Exception e) {
return false;
}
return true;
}
/**
* Checks a single XObject for xObjectsOK. Always returns true.
* Override to implement tests.
*/
protected boolean xObjectOK (PdfDictionary xo)
{
return true;
}
}