SignatureFieldDictionary.java

/*
 * Copyright 2006-2017 ICEsoft Technologies Canada Corp.
 *
 * Licensed 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.
 */

package org.icepdf.core.pobjects.acroform;

import org.icepdf.core.pobjects.Name;
import org.icepdf.core.util.Library;

import java.util.HashMap;

/**
 * Signature field (PDF 1.3) is a form field that contains a digital signature (see 12.8, "Digital Signatures"). The field
 * dictionary representing a signature field may contain the additional entries listed in Table 232, as well as the
 * standard entries described in Table 220. The field type (FT) shall be Sig, and the field value (V), if present, shall
 * be a signature dictionary containing the signature and specifying various attributes of the signature field
 * (see Table 252).
 * <br>
 * NOTE 1This signature form field serves two primary purposes. The first is to define the form field that will provide
 * the visual signing properties for display but it also may hold information needed later when the actual signing takes
 * place, such as the signature technology to use. This carries information from the author of the document to the
 * software that later does the signing.
 * <br>
 * NOTE 2Filling in (signing) the signature field entails updating at least the V entry and usually also the AP entry of
 * the associated widget annotation. Exporting a signature field typically exports the T, V, and AP entries.
 * <br>
 * Like any other field, a signature field may be described by a widget annotation dictionary containing entries pertaining
 * to an annotation as well as a field (see 12.5.6.19, "Widget Annotations"). The annotation rectangle (Rect) in such a
 * dictionary shall give the position of the field on its page. Signature fields that are not intended to be visible shall
 * have an annotation rectangle that has zero height and width. Conforming readers shall treat such signatures as not
 * visible. Conforming readers shall also treat signatures as not visible if either the Hidden bit or the NoView bit of
 * the F entry is true. The F entry is described in Table 164, and annotation flags are described in Table 165.
 *
 * @since 5.2
 */
public class SignatureFieldDictionary extends FieldDictionary {

    /**
     * (Optional; shall be an indirect reference; PDF 1.5) A signature field lock dictionary that specifies a set of form
     * fields that shall be locked when this signature field is signed. Table 233 lists the entries in this dictionary.
     */
    public static final Name LOCK_KEY = new Name("Lock");

    /**
     * (Optional; shall be an indirect reference; PDF 1.5) A seed value dictionary (see Table 234) containing information
     * that constrains the properties of a signature that is applied to this field.
     */
    public static final Name SV_KEY = new Name("SV");

    // optional
    private LockDictionary lockDictionary;
    // optional
    private SeedValueDictionary seedValueDictionary;
    // not optional
    private SignatureDictionary signatureDictionary;

    public SignatureFieldDictionary(Library library, HashMap entries) {
        super(library, entries);

        // get the lock, todo currently no examples of this
        Object tmp = library.getObject(entries, LOCK_KEY);
        if (tmp instanceof HashMap) {
            lockDictionary = new LockDictionary(library, (HashMap) tmp);
        }
        // get the seeds, todo currently no examples of this
        tmp = library.getObject(entries, SV_KEY);
        if (tmp instanceof HashMap) {
            seedValueDictionary = new SeedValueDictionary(library, (HashMap) tmp);
        }
        // get the sig dictionary
        if (hasFieldValue()) {
            tmp = library.getObject(entries, V_KEY);
            if (tmp instanceof HashMap) {
                signatureDictionary = new SignatureDictionary(library, (HashMap) tmp);
            }
        }

    }

    /**
     * Gets the associated signature dictionary and sub dictionaries.
     *
     * @return /sig's field dictionary.
     */
    public SignatureDictionary getSignatureDictionary() {
        return signatureDictionary;
    }

    /**
     * A signature field lock dictionary that specifies a set of form fields that shall be locked when this signature
     * field is signed. Table 233 lists the entries in this dictionary.
     *
     * @return signature field object, can be null.
     */
    public LockDictionary getLockDictionary() {
        return lockDictionary;
    }

    /**
     * A seed value dictionary (see Table 234) containing information that constrains the properties of a signature
     * that is applied to this field.
     *
     * @return seed value object, can be null.
     */
    public SeedValueDictionary getSeedValueDictionary() {
        return seedValueDictionary;
    }
}