ArraySet.java Source code

Introduction

Here is the source code for ArraySet.java

Source

/* Copyright (c) 2006, 2009, Carl Burch. License information is located in the
 * com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

import java.util.AbstractSet;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.NoSuchElementException;

public class ArraySet extends AbstractSet {
    private static final Object[] EMPTY_ARRAY = new Object[0];

    private class ArrayIterator implements Iterator {
        int itVersion = version;
        int pos = 0; // position of next item to return
        boolean hasNext = values.length > 0;
        boolean removeOk = false;

        public boolean hasNext() {
            return hasNext;
        }

        public Object next() {
            if (itVersion != version) {
                throw new ConcurrentModificationException();
            } else if (!hasNext) {
                throw new NoSuchElementException();
            } else {
                Object ret = values[pos];
                ++pos;
                hasNext = pos < values.length;
                removeOk = true;
                return ret;
            }
        }

        public void remove() {
            if (itVersion != version) {
                throw new ConcurrentModificationException();
            } else if (!removeOk) {
                throw new IllegalStateException();
            } else if (values.length == 1) {
                values = EMPTY_ARRAY;
                ++version;
                itVersion = version;
                removeOk = false;
            } else {
                Object[] newValues = new Object[values.length - 1];
                if (pos > 1) {
                    System.arraycopy(values, 0, newValues, 0, pos - 1);
                }
                if (pos < values.length) {
                    System.arraycopy(values, pos, newValues, pos - 1, values.length - pos);
                }
                values = newValues;
                --pos;
                ++version;
                itVersion = version;
                removeOk = false;
            }
        }
    }

    private int version = 0;
    private Object[] values = EMPTY_ARRAY;

    public ArraySet() {
    }

    public Object[] toArray() {
        return values;
    }

    public Object clone() {
        ArraySet ret = new ArraySet();
        if (this.values == EMPTY_ARRAY) {
            ret.values = EMPTY_ARRAY;
        } else {
            ret.values = (Object[]) this.values.clone();
        }
        return ret;
    }

    public void clear() {
        values = EMPTY_ARRAY;
        ++version;
    }

    public boolean isEmpty() {
        return values.length == 0;
    }

    public int size() {
        return values.length;
    }

    public boolean add(Object value) {
        int n = values.length;
        for (int i = 0; i < n; i++) {
            if (values[i].equals(value))
                return false;
        }

        Object[] newValues = new Object[n + 1];
        System.arraycopy(values, 0, newValues, 0, n);
        newValues[n] = value;
        values = newValues;
        ++version;
        return true;
    }

    public boolean contains(Object value) {
        for (int i = 0, n = values.length; i < n; i++) {
            if (values[i].equals(value))
                return true;
        }
        return false;
    }

    public Iterator iterator() {
        return new ArrayIterator();
    }

    public static void main(String[] args) throws java.io.IOException {
        ArraySet set = new ArraySet();
        java.io.BufferedReader in = new java.io.BufferedReader(new java.io.InputStreamReader(System.in));
        while (true) {
            System.out.print(set.size() + ":"); //OK
            for (Iterator it = set.iterator(); it.hasNext();) {
                System.out.print(" " + it.next()); //OK
            }
            System.out.println(); //OK
            System.out.print("> "); //OK
            String cmd = in.readLine();
            if (cmd == null)
                break;
            cmd = cmd.trim();
            if (cmd.equals("")) {
                ;
            } else if (cmd.startsWith("+")) {
                set.add(cmd.substring(1));
            } else if (cmd.startsWith("-")) {
                set.remove(cmd.substring(1));
            } else if (cmd.startsWith("?")) {
                boolean ret = set.contains(cmd.substring(1));
                System.out.println("  " + ret); //OK
            } else {
                System.out.println("unrecognized command"); //OK
            }
        }
    }
}