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package org.apache.padaf.preflight.graphics;
import static org.apache.padaf.preflight.ValidationConstants.DICTIONARY_KEY_TYPE;
import static org.apache.padaf.preflight.ValidationConstants.ERROR_GRAPHIC_INVALID_PATTERN_DEFINITION;
import static org.apache.padaf.preflight.ValidationConstants.PATTERN_KEY_SHADING;
import static org.apache.padaf.preflight.ValidationConstants.PATTERN_KEY_SHADING_TYPE;
import static org.apache.padaf.preflight.ValidationConstants.TRANPARENCY_DICTIONARY_KEY_EXTGSTATE;
import static org.apache.padaf.preflight.ValidationConstants.XOBJECT_DICTIONARY_KEY_COLOR_SPACE;
import java.util.ArrayList;
import java.util.List;
import org.apache.padaf.preflight.DocumentHandler;
import org.apache.padaf.preflight.ValidationException;
import org.apache.padaf.preflight.ValidationResult.ValidationError;
import org.apache.padaf.preflight.graphics.color.ColorSpaceHelper;
import org.apache.padaf.preflight.graphics.color.ColorSpaceHelperFactory;
import org.apache.padaf.preflight.graphics.color.ColorSpaceHelperFactory.ColorSpaceRestriction;
import org.apache.padaf.preflight.utils.COSUtils;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSDocument;
import org.apache.pdfbox.cos.COSName;
/**
* This class process the validation of a ShadingPattern object.
*/
public class ShadingPattern implements XObjectValidator {
/**
* COSDictionary which represent the shading pattern.
*/
private COSDictionary pattern = null;
/**
* The COSDocument which contains the shading pattern to check.
*/
private COSDocument cosDoc = null;
/**
* The document handler which contains useful information to process the
* validation.
*/
private DocumentHandler documentHandler = null;
/**
* @param _handler
* DocumentHandler used to initialize "documentHandler" and "cosDoc"
* attributes.
* @param _pattern
* COSDictionary used to initialize the shading pattern to validate.
*/
public ShadingPattern(DocumentHandler _handler, COSDictionary _pattern) {
this.documentHandler = _handler;
this.pattern = _pattern;
this.cosDoc = this.documentHandler.getDocument().getDocument();
}
/**
* Because of a Shading Pattern can be used as an Indirect Object or Directly
* define in an other dictionary, there are two ways to obtain the Shading
* Pattern dictionary according to the pattern attribute. This method returns
* the Shading pattern dictionary represented by the pattern attribute or
* contained in it.
*
* This is the first method called by the validate method.
*
* @param errors
* the list of error to update if there are no Shading pattern in the
* pattern COSDictionary.
* @return the ShadingPattern dictionary
*/
protected COSDictionary getShadingDictionary(List<ValidationError> errors) {
if (pattern.getItem(COSName.getPDFName(PATTERN_KEY_SHADING_TYPE)) == null
&& !"Shading".equals(pattern.getNameAsString(COSName.getPDFName(DICTIONARY_KEY_TYPE)))) {
COSBase shading = pattern.getItem(COSName.getPDFName(PATTERN_KEY_SHADING));
if (shading == null) {
errors.add(new ValidationError(ERROR_GRAPHIC_INVALID_PATTERN_DEFINITION));
return null;
}
return COSUtils.getAsDictionary(shading, cosDoc);
} else {
return pattern;
}
}
/**
* Checks if the given shading pattern contains the ShadingType entry and if
* the ColorSapce entry is consistent which rules of the PDF Reference and the
* ISO 190005-1:2005 Specification.
*
* This method is called by the validate method.
*
* @param shadingDict
* the Shading pattern dictionary to check
* @param errors
* the list of error to update if the validation fails
* @return true if the Shading pattern is valid, false otherwise.
* @throws ValidationException
*/
protected boolean checkShadingDictionary(COSDictionary shadingDict,
List<ValidationError> errors) throws ValidationException {
if (shadingDict.getItem(COSName.getPDFName(PATTERN_KEY_SHADING_TYPE)) == null) {
errors.add(new ValidationError(ERROR_GRAPHIC_INVALID_PATTERN_DEFINITION));
return false;
}
COSBase csImg = shadingDict.getItem(COSName
.getPDFName(XOBJECT_DICTIONARY_KEY_COLOR_SPACE));
ColorSpaceHelper csh = ColorSpaceHelperFactory.getColorSpaceHelper(csImg,
documentHandler, ColorSpaceRestriction.NO_PATTERN);
return csh.validate(errors);
}
/**
* Check the Extended Graphic State contains in the ShadingPattern dictionary
* if it is present. To check this ExtGState, this method uses the
* net.awl.edoc.pdfa.validation.graphics.ExtGStateContainer object.
*
* @param errors
* the list of error to update if the validation fails
* @return true is the ExtGState is missing or valid, false otherwise.
* @throws ValidationException
*/
protected boolean checkGraphicState(List<ValidationError> errors)
throws ValidationException {
COSDictionary resources = (COSDictionary) this.pattern
.getDictionaryObject(TRANPARENCY_DICTIONARY_KEY_EXTGSTATE);
if (resources != null) {
ExtGStateContainer extContainer = new ExtGStateContainer(resources,
cosDoc);
return extContainer.validateTransparencyRules(errors);
}
return true;
}
/*
* (non-Javadoc)
*
* @see net.awl.edoc.pdfa.validation.graphics.XObjectValidator#validate()
*/
public List<ValidationError> validate() throws ValidationException {
List<ValidationError> result = new ArrayList<ValidationError>();
COSDictionary shading = getShadingDictionary(result);
if (shading != null) {
boolean isValid = checkShadingDictionary(shading, result);
isValid = isValid && checkGraphicState(result);
}
return result;
}
}