java/src/main/com/google/appengine/api/datastore/AppIdNamespace.java

   1 // Copyright 2009 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.datastore;
   4
   5 import com.google.apphosting.api.NamespaceResources;
   6
   7 import java.io.Serializable;
   8
   9 /**
  10  * Abstraction for a "mangled" AppId.  A mangled AppId is a combination
  11  * of the application id and the name_space which this class will
  12  * manage.
  13  *
  14  */
  15 class AppIdNamespace implements Serializable, Comparable<AppIdNamespace> {
  16   private final String appId;
  17   private final String namespace;
  18
  19   private static final String BAD_APP_ID_MESSAGE =
  20       "appId or namespace cannot contain '" + NamespaceResources.NAMESPACE_SEPARATOR + "'";
  21
  22   /**
  23    * Constructs an {@link AppIdNamespace} given {@code #appId} and {@code #namespace}.
  24    */
  25   public AppIdNamespace(String appId, String namespace) {
  26     if (appId == null || namespace == null) {
  27       throw new IllegalArgumentException("appId or namespace may not be null");
  28     }
  29     if (appId.indexOf(NamespaceResources.NAMESPACE_SEPARATOR) != -1 ||
  30         namespace.indexOf(NamespaceResources.NAMESPACE_SEPARATOR) != -1) {
  31       throw new IllegalArgumentException(BAD_APP_ID_MESSAGE);
  32     }
  33     this.appId = appId;
  34     this.namespace = namespace;
  35   }
  36
  37   /**
  38    * Converts an encoded appId/namespace to {@link AppIdNamespace}.
  39    *
  40    * <p>Only one form of an appId/namespace pair will be allowed. i.e. "app!"
  41    * is an illegal form and must be encoded as "app".
  42    *
  43    * <p>An appId/namespace pair may contain at most one "!" character.
  44    *
  45    * @param encodedAppIdNamespace The encoded application Id/namespace string.
  46    */
  47   public static AppIdNamespace parseEncodedAppIdNamespace(String encodedAppIdNamespace) {
  48     if (encodedAppIdNamespace == null) {
  49       throw new IllegalArgumentException("appIdNamespaceString may not be null");
  50     }
  51     int index = encodedAppIdNamespace.indexOf(NamespaceResources.NAMESPACE_SEPARATOR);
  52     if (index == -1) {
  53       return new AppIdNamespace(encodedAppIdNamespace, "");
  54     }
  55     String appId = encodedAppIdNamespace.substring(0, index);
  56     String namespace = encodedAppIdNamespace.substring(index + 1);
  57     if (namespace.length() == 0) {
  58       throw new IllegalArgumentException(
  59           "encodedAppIdNamespace with empty namespace may not contain a '" +
  60           NamespaceResources.NAMESPACE_SEPARATOR + "'");
  61     }
  62     return new AppIdNamespace(appId, namespace);
  63   }
  64
  65   /**
  66    * Perform a "lexical" comparison to {@code other} {@link AppIdNamespace}.
  67    * @return See {@link String#compareTo(String)}.
  68    */
  69   @Override
  70   public int compareTo(AppIdNamespace other) {
  71     int appidCompare = appId.compareTo(other.appId);
  72     if (appidCompare == 0) {
  73       return namespace.compareTo(other.namespace);
  74     }
  75     return appidCompare;
  76   }
  77
  78   public String getAppId() {
  79     return appId;
  80   }
  81
  82   public String getNamespace() {
  83     return namespace;
  84   }
  85
  86   /**
  87    * Returns an "encoded" appId/namespace string.
  88    *
  89    * <p>Note: If the {@link #namespace} is empty, the return value is exactly the {@link #appId}.
  90    */
  91   public String toEncodedString() {
  92     if (namespace.isEmpty()) {
  93       return appId;
  94     } else {
  95       return appId + NamespaceResources.NAMESPACE_SEPARATOR + namespace;
  96     }
  97   }
  98
  99   @Override
 100   public int hashCode() {
 101     final int prime = 31;
 102     int result = 1;
 103     result = prime * result + ((appId == null) ? 0 : appId.hashCode());
 104     result = prime * result + ((namespace == null) ? 0 : namespace.hashCode());
 105     return result;
 106   }
 107
 108   @Override
 109   public boolean equals(Object obj) {
 110     if (this == obj) {
 111       return true;
 112     }
 113     if (obj == null) {
 114       return false;
 115     }
 116     if (getClass() != obj.getClass()) {
 117       return false;
 118     }
 119     AppIdNamespace other = (AppIdNamespace) obj;
 120     if (appId == null) {
 121       if (other.appId != null) {
 122         return false;
 123       }
 124     } else if (!appId.equals(other.appId)) {
 125       return false;
 126     }
 127     if (namespace == null) {
 128       if (other.namespace != null) {
 129         return false;
 130       }
 131     } else if (!namespace.equals(other.namespace)) {
 132       return false;
 133     }
 134     return true;
 135   }
 136
 137   @Override
 138   public String toString() {
 139     return toEncodedString();
 140   }
 141 }