What Is fop.jar? I got it from the fop-2.7-bin.zip.

fop.jar in fop-2.7-bin.zip is the JAR file for FOP 2.7, which is a print formatter driven by XSL formatting objects (XSL-FO). You can obtain fop.jar from the build folder of the fop-2.7-bin.zip file.

Below is the information about the fop.jar (2.2) file:

JAR File Size and Download Location:

JAR name: fop.jar, fop-2.7.jar
Target JDK version: 1.7
File name: fop.jar
File size: 4442817 bytes
Release date: 20-Jan-2022
Download: Apache FOP Website

Java source code files for fop.jar:

⏎ org/apache/fop/complexscripts/fonts/Substitutable.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/* $Id$ */

package org.apache.fop.complexscripts.fonts;

import java.util.List;

// CSOFF: LineLengthCheck

/**
 * <p>Optional interface which indicates that glyph substitution is supported and, if supported,
 * can perform substitution.</p>
 *
 * <p>This work was originally authored by Glenn Adams (gadams@apache.org).</p>
 */
public interface Substitutable {

    /**
     * Determines if font performs glyph substitution.
     * @return true if performs substitution.
     */
    boolean performsSubstitution();

    /**
     * Perform substitutions on characters to effect glyph substitution. If some substitution is performed, it
     * entails mapping from one or more input characters denoting textual character information to one or more
     * output character codes denoting glyphs in this font, where the output character codes may make use of
     * private character code values that have significance only for this font.
     * @param cs character sequence to map to output font encoding character sequence
     * @param script a script identifier
     * @param language a language identifier
     * @param associations optional list to receive list of character associations
     * @param retainControls if true, then retain control characters and their glyph mappings, otherwise remove
     * @return output sequence (represented as a character sequence, where each character in the returned sequence
     * denotes "font characters", i.e., character codes that map directly (1-1) to their associated glyphs
     */
    CharSequence performSubstitution(CharSequence cs, String script, String language, List associations, boolean retainControls);

    /**
     * Reorder combining marks in character sequence so that they precede (within the sequence) the base
     * character to which they are applied. N.B. In the case of LTR segments, marks are not reordered by this,
     * method since when the segment is reversed by BIDI processing, marks are automatically reordered to precede
     * their base character.
     * @param cs character sequence within which combining marks to be reordered
     * @param gpa associated glyph position adjustments (also reordered)
     * @param script a script identifier
     * @param language a language identifier
     * @param associations optional list of associations to be reordered
     * @return output sequence containing reordered "font characters"
     */
    CharSequence reorderCombiningMarks(CharSequence cs, int[][] gpa, String script, String language, List associations);

}

⏎ org/apache/fop/complexscripts/fonts/Substitutable.java

Or download all of them as a single archive file:

File name: fop-2.7-src.zip
File size: 3401312 bytes
Release date: 2022-01-20
Download 

⇒ "fop" Command in fop-2.7-bin.zip

⇐ What Is fop-2.7-bin.zip

⇑ Download and Installing of FOP 2.x

⇑⇑ FAQ for FOP (Formatting Object Processor)