| /* |
| * 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.pdf; |
| |
| import java.io.OutputStream; |
| import java.io.IOException; |
| |
| /** |
| * PDF Filter class. |
| * This represents a PDF filter object. |
| * Filter implementations should extend this class. |
| * |
| * @author Eric SCHAEFFER, Kelly A. Campbell |
| */ |
| public abstract class PDFFilter { |
| /* |
| * These are no longer needed, but are here as a reminder about what |
| * filters pdf supports. |
| * public static final int ASCII_HEX_DECODE = 1; |
| * public static final int ASCII_85_DECODE = 2; |
| * public static final int LZW_DECODE = 3; |
| * public static final int RUN_LENGTH_DECODE = 4; |
| * public static final int CCITT_FAX_DECODE = 5; |
| * public static final int DCT_DECODE = 6; |
| * public static final int FLATE_DECODE = 7; |
| */ |
| |
| /** |
| * Marker to know if this filter has already been applied to the data |
| */ |
| private boolean applied = false; |
| |
| /** |
| * Check if this filter has been applied. |
| * |
| * @return true if this filter has been applied |
| */ |
| public boolean isApplied() { |
| return applied; |
| } |
| |
| /** |
| * Set the applied attribute to the given value. This attribute is |
| * used to determine if this filter is just a placeholder for the |
| * decodeparms and dictionary entries, or if the filter needs to |
| * actually encode the data. For example if the raw data is copied |
| * out of an image file in it's compressed format, then this |
| * should be set to true and the filter options should be set to |
| * those which the raw data was encoded with. |
| * |
| * @param b set the applied value to this |
| */ |
| public void setApplied(boolean b) { |
| applied = b; |
| } |
| |
| /** |
| * return a PDF string representation of the filter, e.g. /FlateDecode |
| * |
| * @return the filter PDF name |
| */ |
| public abstract String getName(); |
| |
| /** |
| * Returns true if the filter is an ASCII filter that isn't necessary |
| * when encryption is active. |
| * @return boolean True if this filter is an ASCII filter |
| */ |
| public boolean isASCIIFilter() { |
| return false; |
| } |
| |
| /** |
| * return a parameter dictionary for this filter, or null |
| * |
| * @return the decode params for the filter |
| */ |
| public abstract PDFObject getDecodeParms(); |
| |
| /** |
| * Applies a filter to an OutputStream. |
| * @param out contents to be filtered |
| * @return OutputStream filtered contents |
| * @throws IOException In case of an I/O problem |
| */ |
| public abstract OutputStream applyFilter(OutputStream out) throws IOException; |
| |
| } |