public static String readFixedString(DataInput in, int length) throws IOException {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
char c = in.readChar();
// if char is not Unicode zero add to string
if (c != 0) sb.append(c);
}
return sb.toString();
}
/**
* Reads a primitive value of the specified class type from the stream.
*
* @param in A stream to read from.
* @param cls A class type of the primitive.
* @return A primitive.
* @throws IOException If an I/O error occurs.
*/
static Object readPrimitive(DataInput in, Class cls) throws IOException {
if (cls == byte.class) return in.readByte();
if (cls == short.class) return in.readShort();
if (cls == int.class) return in.readInt();
if (cls == long.class) return in.readLong();
if (cls == float.class) return in.readFloat();
if (cls == double.class) return in.readDouble();
if (cls == boolean.class) return in.readBoolean();
if (cls == char.class) return in.readChar();
throw new IllegalArgumentException();
}
/** Read a {@link Writable}, {@link String}, primitive type, or an array of the preceding. */
@SuppressWarnings("unchecked")
public static Object readObject(DataInput in, ObjectWritable objectWritable, Configuration conf)
throws IOException {
String className = UTF8.readString(in);
Class<?> declaredClass = PRIMITIVE_NAMES.get(className);
if (declaredClass == null) {
declaredClass = loadClass(conf, className);
}
Object instance;
if (declaredClass.isPrimitive()) { // primitive types
if (declaredClass == Boolean.TYPE) { // boolean
instance = Boolean.valueOf(in.readBoolean());
} else if (declaredClass == Character.TYPE) { // char
instance = Character.valueOf(in.readChar());
} else if (declaredClass == Byte.TYPE) { // byte
instance = Byte.valueOf(in.readByte());
} else if (declaredClass == Short.TYPE) { // short
instance = Short.valueOf(in.readShort());
} else if (declaredClass == Integer.TYPE) { // int
instance = Integer.valueOf(in.readInt());
} else if (declaredClass == Long.TYPE) { // long
instance = Long.valueOf(in.readLong());
} else if (declaredClass == Float.TYPE) { // float
instance = Float.valueOf(in.readFloat());
} else if (declaredClass == Double.TYPE) { // double
instance = Double.valueOf(in.readDouble());
} else if (declaredClass == Void.TYPE) { // void
instance = null;
} else {
throw new IllegalArgumentException("Not a primitive: " + declaredClass);
}
} else if (declaredClass.isArray()) { // array
int length = in.readInt();
instance = Array.newInstance(declaredClass.getComponentType(), length);
for (int i = 0; i < length; i++) {
Array.set(instance, i, readObject(in, conf));
}
} else if (declaredClass == String.class) { // String
instance = UTF8.readString(in);
} else if (declaredClass.isEnum()) { // enum
instance = Enum.valueOf((Class<? extends Enum>) declaredClass, UTF8.readString(in));
} else { // Writable
Class instanceClass = null;
String str = UTF8.readString(in);
instanceClass = loadClass(conf, str);
Writable writable = WritableFactories.newInstance(instanceClass, conf);
writable.readFields(in);
instance = writable;
if (instanceClass == NullInstance.class) { // null
declaredClass = ((NullInstance) instance).declaredClass;
instance = null;
}
}
if (objectWritable != null) { // store values
objectWritable.declaredClass = declaredClass;
objectWritable.instance = instance;
}
return instance;
}
