/**
* Reads the area code entries from the provided input stream and stores them to the internal byte
* buffers.
*/
private void readEntries(ObjectInput objectInput)
{
numOfEntries = objectInput.readInt();
if (phoneNumberPrefixes == null || phoneNumberPrefixes.capacity() < numOfEntries) {
phoneNumberPrefixes = ByteBuffer.allocate(numOfEntries * prefixSizeInBytes);
}
if (descriptionIndexes == null || descriptionIndexes.capacity() < numOfEntries) {
descriptionIndexes = ByteBuffer.allocate(numOfEntries * descIndexSizeInBytes);
}
for (int i = 0; i < numOfEntries; i++) {
readExternalWord(objectInput, prefixSizeInBytes, phoneNumberPrefixes, i);
readExternalWord(objectInput, descIndexSizeInBytes, descriptionIndexes, i);
}
}
public override void readFromSortedMap(SortedMap<Integer, String> areaCodeMap)
{
SortedSet<String> descriptionsSet = new TreeSet<String>();
numOfEntries = areaCodeMap.size();
prefixSizeInBytes = getOptimalNumberOfBytesForValue(areaCodeMap.lastKey());
phoneNumberPrefixes = ByteBuffer.allocate(numOfEntries * prefixSizeInBytes);
// Fill the phone number prefixes byte buffer, the set of possible lengths of prefixes and the
// description set.
int index = 0;
foreach (Entry<Integer, String> entry in areaCodeMap.entrySet()) {
int prefix = entry.getKey();
storeWordInBuffer(phoneNumberPrefixes, prefixSizeInBytes, index, prefix);
possibleLengths.add((int) Math.log10(prefix) + 1);
descriptionsSet.add(entry.getValue());
++index;
}
createDescriptionPool(descriptionsSet, areaCodeMap);
}
/**
* Creates the description pool from the provided set of string descriptions and area code map.
*/
private void createDescriptionPool(SortedSet<String> descriptionsSet,
SortedMap<Integer, String> areaCodeMap)
{
descIndexSizeInBytes = getOptimalNumberOfBytesForValue(descriptionsSet.size() - 1);
descriptionIndexes = ByteBuffer.allocate(numOfEntries * descIndexSizeInBytes);
descriptionPool = new String[descriptionsSet.size()];
descriptionsSet.toArray(descriptionPool);
// Map the phone number prefixes to the descriptions.
int index = 0;
for (int i = 0; i < numOfEntries; i++) {
int prefix = readWordFromBuffer(phoneNumberPrefixes, prefixSizeInBytes, i);
String description = areaCodeMap.get(prefix);
int positionInDescriptionPool = Arrays.binarySearch(descriptionPool, description);
storeWordInBuffer(descriptionIndexes, descIndexSizeInBytes, index, positionInDescriptionPool);
++index;
}
}
/**
* Writes the value read from the provided byte {@code buffer} at the specified {@code index} to
* the provided {@code objectOutput}.
*
* @param objectOutput the object output stream to which the value is written
* @param wordSize the number of bytes used to store the value
* @param inputBuffer the byte buffer from which the value is read
* @param index the index of the value in the the byte buffer
* @throws IOException if an error occurred writing to the provided object output stream
*/
private static void writeExternalWord(ObjectOutput objectOutput, int wordSize,
ByteBuffer inputBuffer, int index)
{
int wordIndex = index * wordSize;
if (wordSize == SHORT_NUM_BYTES) {
objectOutput.writeShort(inputBuffer.getShort(wordIndex));
} else {
objectOutput.writeInt(inputBuffer.getInt(wordIndex));
}
}
/**
* Stores the provided {@code value} to the provided byte {@code buffer} at the specified {@code
* index} using the provided {@code wordSize} in bytes. Note that only integer and short sizes are
* supported.
*
* @param buffer the byte buffer to which the value is stored
* @param wordSize the number of bytes used to store the provided value
* @param index the index to which the value is stored
* @param value the value that is stored assuming it does not require more than the specified
* number of bytes.
*/
private static void storeWordInBuffer(ByteBuffer buffer, int wordSize, int index, int value)
{
int wordIndex = index * wordSize;
if (wordSize == SHORT_NUM_BYTES) {
buffer.putShort(wordIndex, (short) value);
} else {
buffer.putInt(wordIndex, value);
}
}
/**
* Reads the {@code value} at the specified {@code index} from the provided byte {@code buffer}.
* Note that only integer and short sizes are supported.
*
* @param buffer the byte buffer from which the value is read
* @param wordSize the number of bytes used to store the value
* @param index the index where the value is read from
*
* @return the value read from the buffer
*/
private static int readWordFromBuffer(ByteBuffer buffer, int wordSize, int index)
{
int wordIndex = index * wordSize;
return wordSize == SHORT_NUM_BYTES ? buffer.getShort(wordIndex) : buffer.getInt(wordIndex);
}
/**
* Stores a value which is read from the provided {@code objectInput} to the provided byte {@code
* buffer} at the specified {@code index}.
*
* @param objectInput the object input stream from which the value is read
* @param wordSize the number of bytes used to store the value read from the stream
* @param outputBuffer the byte buffer to which the value is stored
* @param index the index where the value is stored in the buffer
* @throws IOException if an error occurred reading from the object input stream
*/
private static void readExternalWord(ObjectInput objectInput, int wordSize,
ByteBuffer outputBuffer, int index)
{
int wordIndex = index * wordSize;
if (wordSize == SHORT_NUM_BYTES) {
outputBuffer.putShort(wordIndex, objectInput.readShort());
} else {
outputBuffer.putInt(wordIndex, objectInput.readInt());
}
}