org.zorbaxquery.modules.readPdf.GetImages.java Source code

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Here is the source code for org.zorbaxquery.modules.readPdf.GetImages.java

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/*
 * Copyright 2006-2012 The FLWOR Foundation.
 *
 * 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.zorbaxquery.modules.readPdf;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.common.PDMetadata;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectImage;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * Sample code to extract the images embedded into Pdf documents
 */
public class GetImages {
    private int imageCounter = 0;

    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println("USAGE: GetImages file.pdf");
            return;
        }

        GetImages gi = new GetImages();
        gi.getXMPInformation(args[0]);
    }

    public void getXMPInformation(String path) {
        // Open PDF document
        PDDocument document = null;
        try {
            document = PDDocument.load(path);
        } catch (IOException e) {
            e.printStackTrace();
        }
        // Get all pages and loop through them
        List pages = document.getDocumentCatalog().getAllPages();
        Iterator iter = pages.iterator();
        int pageNo = 1;
        while (iter.hasNext()) {
            System.out.println("Examining page " + pageNo++ + " :");
            PDPage page = (PDPage) iter.next();
            PDResources resources = page.getResources();
            Map images = null;
            // Get all Images on page
            try {
                images = resources.getImages();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (images != null) {
                // Check all images for metadata
                Iterator imageIter = images.keySet().iterator();
                while (imageIter.hasNext()) {
                    String key = (String) imageIter.next();
                    PDXObjectImage image = (PDXObjectImage) images.get(key);
                    PDMetadata metadata = image.getMetadata();
                    System.out.println("Found a image: Analyzing for Metadata");
                    if (metadata == null) {
                        System.out.println("No Metadata found for this image.");
                        System.out.println(
                                "image: " + image.getWidth() + "x" + image.getHeight() + " " + image.getSuffix());
                        try {
                            System.out.println("       bitsPerComponent: " + image.getBitsPerComponent()
                                    + "  colorSpace: " + image.getColorSpace().getName() + "  hasImageMask: "
                                    + image.getImageMask());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    } else {
                        InputStream xmlInputStream = null;
                        try {
                            xmlInputStream = metadata.createInputStream();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        try {
                            System.out.println(
                                    "--------------------------------------------------------------------------------");
                            String mystring = convertStreamToString(xmlInputStream);
                            System.out.println(mystring);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    // Export the images
                    String name = getUniqueFileName(key, image.getSuffix());
                    System.out.println("Writing image:" + name);
                    try {
                        //image.write2file(name);
                        File f = new File(name);
                        OutputStream os = new FileOutputStream(f);
                        image.write2OutputStream(os);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    System.out.println(
                            "--------------------------------------------------------------------------------");
                }
            }
        }
    }

    public String convertStreamToString(InputStream is) throws IOException {
        /*
         * To convert the InputStream to String we use the BufferedReader.readLine()
         * method. We iterate until the BufferedReader return null which means
         * there's no more data to read. Each line will appended to a StringBuilder
         * and returned as String.
         */
        if (is != null) {
            StringBuilder sb = new StringBuilder();
            String line;

            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                while ((line = reader.readLine()) != null) {
                    sb.append(line).append("\n");
                }
            } finally {
                is.close();
            }
            return sb.toString();
        } else {
            return "";
        }
    }

    private String getUniqueFileName(String prefix, String suffix) {
        String uniqueName = null;
        File f = null;
        while (f == null || f.exists()) {
            uniqueName = prefix + "-" + imageCounter + "." + suffix;
            f = new File(uniqueName);
            imageCounter++;
        }

        return uniqueName;
    }

}