gson/com/google/gson/JsonArray.java

   1 /*
   2  * Copyright (C) 2008 Google Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package com.google.gson;
  18
  19 import java.math.BigDecimal;
  20 import java.math.BigInteger;
  21 import java.util.ArrayList;
  22 import java.util.Iterator;
  23 import java.util.List;
  24
  25 /**
  26  * A class representing an array type in Json. An array is a list of {@link JsonElement}s each of
  27  * which can be of a different type. This is an ordered list, meaning that the order in which
  28  * elements are added is preserved.
  29  *
  30  * @author Inderjeet Singh
  31  * @author Joel Leitch
  32  */
  33 public final class JsonArray extends JsonElement implements Iterable<JsonElement> {
  34   private final List<JsonElement> elements;
  35
  36   /**
  37    * Creates an empty JsonArray.
  38    */
  39   public JsonArray() {
  40     elements = new ArrayList<JsonElement>();
  41   }
  42
  43   @Override
  44   JsonArray deepCopy() {
  45     JsonArray result = new JsonArray();
  46     for (JsonElement element : elements) {
  47       result.add(element.deepCopy());
  48     }
  49     return result;
  50   }
  51
  52   /**
  53    * Adds the specified element to self.
  54    *
  55    * @param element the element that needs to be added to the array.
  56    */
  57   public void add(JsonElement element) {
  58     if (element == null) {
  59       element = JsonNull.INSTANCE;
  60     }
  61     elements.add(element);
  62   }
  63
  64   /**
  65    * Adds all the elements of the specified array to self.
  66    *
  67    * @param array the array whose elements need to be added to the array.
  68    */
  69   public void addAll(JsonArray array) {
  70     elements.addAll(array.elements);
  71   }
  72
  73   /**
  74    * Returns the number of elements in the array.
  75    *
  76    * @return the number of elements in the array.
  77    */
  78   public int size() {
  79     return elements.size();
  80   }
  81
  82   /**
  83    * Returns an iterator to navigate the elemetns of the array. Since the array is an ordered list,
  84    * the iterator navigates the elements in the order they were inserted.
  85    *
  86    * @return an iterator to navigate the elements of the array.
  87    */
  88   public Iterator<JsonElement> iterator() {
  89     return elements.iterator();
  90   }
  91
  92   /**
  93    * Returns the ith element of the array.
  94    *
  95    * @param i the index of the element that is being sought.
  96    * @return the element present at the ith index.
  97    * @throws IndexOutOfBoundsException if i is negative or greater than or equal to the
  98    * {@link #size()} of the array.
  99    */
 100   public JsonElement get(int i) {
 101     return elements.get(i);
 102   }
 103
 104   /**
 105    * convenience method to get this array as a {@link Number} if it contains a single element.
 106    *
 107    * @return get this element as a number if it is single element array.
 108    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 109    * is not a valid Number.
 110    * @throws IllegalStateException if the array has more than one element.
 111    */
 112   @Override
 113   public Number getAsNumber() {
 114     if (elements.size() == 1) {
 115       return elements.get(0).getAsNumber();
 116     }
 117     throw new IllegalStateException();
 118   }
 119
 120   /**
 121    * convenience method to get this array as a {@link String} if it contains a single element.
 122    *
 123    * @return get this element as a String if it is single element array.
 124    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 125    * is not a valid String.
 126    * @throws IllegalStateException if the array has more than one element.
 127    */
 128   @Override
 129   public String getAsString() {
 130     if (elements.size() == 1) {
 131       return elements.get(0).getAsString();
 132     }
 133     throw new IllegalStateException();
 134   }
 135
 136   /**
 137    * convenience method to get this array as a double if it contains a single element.
 138    *
 139    * @return get this element as a double if it is single element array.
 140    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 141    * is not a valid double.
 142    * @throws IllegalStateException if the array has more than one element.
 143    */
 144   @Override
 145   public double getAsDouble() {
 146     if (elements.size() == 1) {
 147       return elements.get(0).getAsDouble();
 148     }
 149     throw new IllegalStateException();
 150   }
 151
 152   /**
 153    * convenience method to get this array as a {@link BigDecimal} if it contains a single element.
 154    *
 155    * @return get this element as a {@link BigDecimal} if it is single element array.
 156    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive}.
 157    * @throws NumberFormatException if the element at index 0 is not a valid {@link BigDecimal}.
 158    * @throws IllegalStateException if the array has more than one element.
 159    * @since 1.2
 160    */
 161   @Override
 162   public BigDecimal getAsBigDecimal() {
 163     if (elements.size() == 1) {
 164       return elements.get(0).getAsBigDecimal();
 165     }
 166     throw new IllegalStateException();
 167   }
 168
 169   /**
 170    * convenience method to get this array as a {@link BigInteger} if it contains a single element.
 171    *
 172    * @return get this element as a {@link BigInteger} if it is single element array.
 173    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive}.
 174    * @throws NumberFormatException if the element at index 0 is not a valid {@link BigInteger}.
 175    * @throws IllegalStateException if the array has more than one element.
 176    * @since 1.2
 177    */
 178   @Override
 179   public BigInteger getAsBigInteger() {
 180     if (elements.size() == 1) {
 181       return elements.get(0).getAsBigInteger();
 182     }
 183     throw new IllegalStateException();
 184   }
 185
 186   /**
 187    * convenience method to get this array as a float if it contains a single element.
 188    *
 189    * @return get this element as a float if it is single element array.
 190    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 191    * is not a valid float.
 192    * @throws IllegalStateException if the array has more than one element.
 193    */
 194   @Override
 195   public float getAsFloat() {
 196     if (elements.size() == 1) {
 197       return elements.get(0).getAsFloat();
 198     }
 199     throw new IllegalStateException();
 200   }
 201
 202   /**
 203    * convenience method to get this array as a long if it contains a single element.
 204    *
 205    * @return get this element as a long if it is single element array.
 206    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 207    * is not a valid long.
 208    * @throws IllegalStateException if the array has more than one element.
 209    */
 210   @Override
 211   public long getAsLong() {
 212     if (elements.size() == 1) {
 213       return elements.get(0).getAsLong();
 214     }
 215     throw new IllegalStateException();
 216   }
 217
 218   /**
 219    * convenience method to get this array as an integer if it contains a single element.
 220    *
 221    * @return get this element as an integer if it is single element array.
 222    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 223    * is not a valid integer.
 224    * @throws IllegalStateException if the array has more than one element.
 225    */
 226   @Override
 227   public int getAsInt() {
 228     if (elements.size() == 1) {
 229       return elements.get(0).getAsInt();
 230     }
 231     throw new IllegalStateException();
 232   }
 233
 234   @Override
 235   public byte getAsByte() {
 236     if (elements.size() == 1) {
 237       return elements.get(0).getAsByte();
 238     }
 239     throw new IllegalStateException();
 240   }
 241
 242   @Override
 243   public char getAsCharacter() {
 244     if (elements.size() == 1) {
 245       return elements.get(0).getAsCharacter();
 246     }
 247     throw new IllegalStateException();
 248   }
 249
 250   /**
 251    * convenience method to get this array as a primitive short if it contains a single element.
 252    *
 253    * @return get this element as a primitive short if it is single element array.
 254    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 255    * is not a valid short.
 256    * @throws IllegalStateException if the array has more than one element.
 257    */
 258   @Override
 259   public short getAsShort() {
 260     if (elements.size() == 1) {
 261       return elements.get(0).getAsShort();
 262     }
 263     throw new IllegalStateException();
 264   }
 265
 266   /**
 267    * convenience method to get this array as a boolean if it contains a single element.
 268    *
 269    * @return get this element as a boolean if it is single element array.
 270    * @throws ClassCastException if the element in the array is of not a {@link JsonPrimitive} and
 271    * is not a valid boolean.
 272    * @throws IllegalStateException if the array has more than one element.
 273    */
 274   @Override
 275   public boolean getAsBoolean() {
 276     if (elements.size() == 1) {
 277       return elements.get(0).getAsBoolean();
 278     }
 279     throw new IllegalStateException();
 280   }
 281
 282   @Override
 283   public boolean equals(Object o) {
 284     return (o == this) || (o instanceof JsonArray && ((JsonArray) o).elements.equals(elements));
 285   }
 286
 287   @Override
 288   public int hashCode() {
 289     return elements.hashCode();
 290   }
 291 }