java/src/main/com/google/appengine/api/conversion/ConversionOptions.java

   1 // Copyright 2011 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.conversion;
   4
   5 import com.google.common.base.Objects;
   6 import com.google.common.base.Preconditions;
   7 import com.google.common.base.StringUtil;
   8
   9 /**
  10  * The options for a conversion following builder pattern. This class also
  11  * defines default values for most options.
  12  *
  13  */
  14 public final class ConversionOptions {
  15
  16   private Integer imageWidth = 800;
  17
  18   private Integer firstPage = 1;
  19
  20   private Integer lastPage = -1;
  21    private String ocrInputLanguage;
  22
  23   private ConversionOptions() {}
  24
  25   /**
  26    * Sets the output image width in pixels. Only applies to
  27    * conversions that generate image files.
  28    *
  29    * @param imageWidth the output image width in pixels
  30    * @return this ConversionOptions instance for chaining
  31    * @throws IllegalArgumentException if imageWidth is not positive
  32    */
  33   public ConversionOptions imageWidth(int imageWidth) {
  34     Preconditions.checkArgument(imageWidth > 0, "image width must be > 0, got " + imageWidth);
  35     this.imageWidth = imageWidth;
  36     return this;
  37   }
  38
  39   /**
  40    * Sets the number of the first page to generate. Only applies to
  41    * conversions that generate image files.
  42    *
  43    * @param firstPage the number of the first page to generate
  44    * @return this ConversionOptions instance for chaining
  45    * @throws IllegalArgumentException if firstPage is not positive
  46    */
  47   public ConversionOptions firstPage(int firstPage) {
  48     Preconditions.checkArgument(firstPage > 0, "first page must be > 0, got " + firstPage);
  49     this.firstPage = firstPage;
  50     return this;
  51   }
  52
  53   /**
  54    * Sets the number of the last page to generate, defaults to the last page
  55    * of the document. Only applies to conversions that generate image files.
  56    *
  57    * @param lastPage the number of the last page to generate
  58    * @return this ConversionOptions instance for chaining
  59    * @throws IllegalArgumentException if lastPage is not positive
  60    */
  61   public ConversionOptions lastPage(int lastPage) {
  62     Preconditions.checkArgument(lastPage > 0, "last page must be > 0, got " + lastPage);
  63     this.lastPage = lastPage;
  64     return this;
  65   }
  66
  67   /**
  68    * Sets the language code in BCP 47 format, used by OCR engine to search for
  69    * language-specific character set.
  70    *
  71    * @param ocrInputLanguage the language code used by OCR engine
  72    * @return this ConversionOptions instance for chaining
  73    * @throws IllegalArgumentException if ocrInputLanguage is null, empty or
  74    *         comprises only whitespace characters
  75    */
  76   public ConversionOptions ocrInputLanguage(String ocrInputLanguage) {
  77     Preconditions.checkArgument(!StringUtil.isEmptyOrWhitespace(ocrInputLanguage),
  78         "OCR input language should not be null, empty or comprises only whitespace characters");
  79     this.ocrInputLanguage = ocrInputLanguage.toLowerCase();
  80     return this;
  81   }
  82
  83   /**
  84    * Returns the output image width in pixels.
  85    */
  86   Integer getImageWidth() {
  87     return imageWidth;
  88   }
  89
  90   /**
  91    * Returns the number of the first page to generate.
  92    */
  93   Integer getFirstPage() {
  94     return firstPage;
  95   }
  96
  97   /**
  98    * Returns the number of the last page to generate.
  99    */
 100   Integer getLastPage() {
 101     return lastPage;
 102   }
 103
 104   /**
 105    * Returns the language code used by OCR engine, or null if not present.
 106    */
 107   String getOcrInputLanguage() {
 108     return ocrInputLanguage;
 109   }
 110
 111   @Override
 112   public boolean equals(Object o) {
 113     if (this == o) {
 114       return true;
 115     }
 116     if (o == null || getClass() != o.getClass()) {
 117       return false;
 118     }
 119
 120     ConversionOptions other = (ConversionOptions) o;
 121     return Objects.equal(imageWidth, other.getImageWidth())
 122            && Objects.equal(firstPage, other.getFirstPage())
 123            && Objects.equal(lastPage, other.getLastPage())
 124            && Objects.equal(ocrInputLanguage, other.getOcrInputLanguage());
 125   }
 126
 127   @Override
 128   public int hashCode() {
 129     return Objects.hashCode(imageWidth, firstPage, lastPage, ocrInputLanguage);
 130   }
 131
 132   /**
 133    * Provides static creation methods for {@link ConversionOptions}.
 134    */
 135   public static final class Builder {
 136
 137     private Builder() {}
 138
 139     /**
 140      * Returns a {@link ConversionOptions} with default values.
 141      */
 142     public static ConversionOptions withDefaults() {
 143       return new ConversionOptions();
 144     }
 145
 146     /**
 147      * Returns a {@link ConversionOptions} with specified output image width.
 148      */
 149     public static ConversionOptions withImageWidth(int imageWidth) {
 150       return withDefaults().imageWidth(imageWidth);
 151     }
 152
 153     /**
 154      * Returns a {@link ConversionOptions} with specified number of first page.
 155      */
 156     public static ConversionOptions withFirstPage(int firstPage) {
 157       return withDefaults().firstPage(firstPage);
 158     }
 159
 160     /**
 161      * Returns a {@link ConversionOptions} with specified number of last page.
 162      */
 163     public static ConversionOptions withLastPage(int lastPage) {
 164       return withDefaults().lastPage(lastPage);
 165     }
 166
 167     /**
 168      * Returns a {@link ConversionOptions} with specified language code for OCR.
 169      */
 170     public static ConversionOptions withOcrInputLanguage(String ocrInputLanguage) {
 171       return withDefaults().ocrInputLanguage(ocrInputLanguage);
 172     }
 173   }
 174 }