java/src/main/com/google/appengine/api/conversion/Document.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.collect.Lists;
   8
   9 import java.util.Collections;
  10 import java.util.List;
  11
  12 /**
  13  * An immutable document for conversion. A document must contain at least one
  14  * asset, typically the document contents. Additional assets are those needed
  15  * for the conversion, for example images in HTML.
  16  *
  17  */
  18 public final class Document {
  19
  20   private final List<Asset> assets = Lists.newArrayList();
  21
  22   /**
  23    * Constructs a document.
  24    *
  25    * @param firstAsset the first asset to add
  26    */
  27   public Document(Asset firstAsset) {
  28     assets.add(Preconditions.checkNotNull(firstAsset));
  29   }
  30
  31   /**
  32    * Constructs a document.
  33    *
  34    * @param assets a list of assets to add
  35    * @throws IllegalArgumentException if the assets list is empty
  36    */
  37   public Document(List<Asset> assets) {
  38     Preconditions.checkNotNull(assets);
  39     Preconditions.checkArgument(assets.size() > 0, "The assets list should not be empty");
  40     this.assets.addAll(assets);
  41   }
  42
  43   /**
  44    * Returns all assets associated with the document.
  45    */
  46   public List<Asset> getAssets() {
  47     return Collections.unmodifiableList(assets);
  48   }
  49
  50   @Override
  51   public boolean equals(Object o) {
  52     if (this == o) {
  53       return true;
  54     }
  55     if (o == null || getClass() != o.getClass()) {
  56       return false;
  57     }
  58
  59     return Objects.equal(assets, ((Document) o).getAssets());
  60   }
  61
  62   @Override
  63   public int hashCode() {
  64     return Objects.hashCode(assets);
  65   }
  66 }