FileDocCategorySizeDatePackage
Str2ID.javaAPI DocJ2ME CLDC 1.14893Wed Feb 05 15:56:02 GMT 2003jcc

Str2ID

public class Str2ID extends Object

Fields Summary
public int
hashTableSize
public int
used
public int
baseId
public Str2ID
next
public components.UnicodeConstant[]
strings
public components.StringConstant[]
parameters
public int[]
hashbits
boolean
locked
public static final int
DEFAULT_hashTableSize
int
overflowPoint
public static Str2ID
sigHash
Constructors Summary
public Str2ID()


       
        this(DEFAULT_hashTableSize, true);
public Str2ID(int size)

 
        this(size, false);
private Str2ID(int size, boolean knownPrime)

 
        if (!knownPrime) { 
        size |= 1;
        while (!isPrime(size))
            size += 2;
    }
    hashTableSize = size;
    strings = new UnicodeConstant[size];
    hashbits = new int[size];
    overflowPoint = (int)(hashTableSize * 0.8);
Methods Summary
public intgetID(components.UnicodeConstant str, components.StringConstant parameter)

    Str2ID head = this;
    int index;
    int hash = hashString(str.string);
    int phash = hash & 0x7fffffff;
    int secondaryHash = (hash & 7) + 1;

    Str2ID chain = head;
    for ( ; ; ) {
        index = chain.unsignedMod(hash);
        while (chain.strings[index] != null) {
        if ((chain.hashbits[index] == phash) &&
            chain.strings[index].string.equals(str.string)) {
            // We found the string, calculate the ID
            return chain.baseId + index;
        }
        index -= secondaryHash;
        if (index < 0) {
            index += chain.hashTableSize;
        }
        }

        // Didn't find the string in this chain. . . .
        if (chain.next == null) { 
            break;
        } else { 
            chain = chain.next;
        }
    }

    if (locked) { 
        throw new NullPointerException(
        Localizer.getString("str2id.attempting_to_add_to_table_when_locked", str));

    }
    if (chain.used >= chain.overflowPoint) {
        chain.next = new Str2ID();
        chain.next.baseId = chain.baseId + chain.hashTableSize;
        chain = chain.next;
        index = chain.unsignedMod(hash);
    }

    chain.strings[index] = str;
    chain.hashbits[index] = phash;
    if (parameter != null ){
        if ( chain.parameters == null ){
        chain.parameters = new StringConstant[chain.hashTableSize];
        }
        chain.parameters[index] = parameter;
    }
    chain.used++;
    return chain.baseId + index;
public intgetID(java.lang.String str)

    return getID( new UnicodeConstant( str ), (StringConstant)null );
public intgetID(components.UnicodeConstant name, components.UnicodeConstant sig)

    return (getID( name, (StringConstant)null) << 16) + getID( sig, (StringConstant)null);
public intgetID(java.lang.String name, java.lang.String sig)

    return (getID(name) << 16) + getID(sig);
static inthashString(java.lang.String str)

    int result = 0;
    for (int i = 0; i < str.length(); i++) {
        result = result * 37 + (int) str.charAt(i);
    }

    return result;
static booleanisPrime(int n)

        if ((n % 2) == 0)
        return false;
    int sqrt = (int) Math.sqrt(n);
    for (int i = 3; i <= sqrt; i += 2) { 
        if ((n % i) == 0)
            return false;
    }
    return true;
public jcc.Str2IDrehash()

        Str2ID newchain, chain;
    int count = 0;
    for (chain = this; chain != null; chain = chain.next) {
        count += chain.used;
    }
    newchain = new Str2ID((int)Math.ceil(1.25 * count));

    for (chain = this; chain != null; chain = chain.next) {
        UnicodeConstant strings[] = chain.strings;
        StringConstant  parameters[] = chain.parameters;
        for (int i = chain.hashTableSize; --i >= 0; ) { 
            UnicodeConstant string = strings[i];
        if (string != null) 
            newchain.getID(string, parameters == null ? null : parameters[i]);
        }
    }
    return newchain;
public voidsetLocked(boolean lock)

 
        this.locked = lock;
intunsignedMod(int val)


    // Treat val as an unsigned quantity and do the MOD operation
       
    if (val >= 0) {
        return val % hashTableSize;
    } else {
        return (int)(((long)val&0xffffffffL) % (long)hashTableSize);
    }