package com.ora.rmibook.chapter15;


import java.util.*;
import java.io.*;


/*
 Note that if you call equals or compareto
 at the same time from instances, a deadlock
 can result.

 Recommendation: don't do that.
 */

public class AttributeSet implements Serializable, Comparable {
    private TreeMap _underlyingMap;

    public AttributeSet() {
        _underlyingMap = new TreeMap();
    }

    public synchronized void add(String name, String value) {
        if (null == name) {
            return;
        }
        if (null == value) {
            _underlyingMap.remove(name);
        } else {
            _underlyingMap.put(name, value);
        }
    }

    public synchronized void remove(String name) {
        _underlyingMap.remove(name);
    }

    public synchronized int getSize() {
        return _underlyingMap.size();
    }

    public synchronized Iterator getNames() {
        return _underlyingMap.keySet().iterator();
    }

    public synchronized String getValue(String name) {
        return (String) _underlyingMap.get(name);
    }

    public synchronized boolean contains(String name) {
        return (null != _underlyingMap.get(name));
    }

    public synchronized boolean contains(String name, String value) {
        String internalValue = (String) _underlyingMap.get(name);

        if (null != internalValue) {
            return internalValue.equals(value);
        }
        return null == value;
    }

    public synchronized boolean equals(Object object) {
        if (null == object) {
            return false;
        }
        if (false == (object instanceof AttributeSet)) {
            return false;
        }
        return (0 == compareTo(object));
    }

    public synchronized boolean subsetOf(AttributeSet otherAttributeSet) {
        if (null == otherAttributeSet) {
            return false;
        }
        Iterator i = getNames();

        while (i.hasNext()) {
            String name = (String) i.next();
            String value = getValue(name);

            if (false == otherAttributeSet.contains(name, value)) {
                return false;
            }
        }
        return true;
    }
    
    public synchronized int compareTo(Object object) {
        if (null == object) {
            return -1;
        }
        AttributeSet otherAttributeSet = (AttributeSet) object;
        int sizeDifferential = _underlyingMap.size() - otherAttributeSet.getSize();

        if (0 != sizeDifferential) {
            return (sizeDifferential > 0) ? -1 : 1;   //doesn't matter as long as we're consistent.
        }
        Iterator otherIterator = otherAttributeSet.getNames();
        Iterator internalIterator = getNames();

        while (otherIterator.hasNext()) {
            String foreignName = (String) otherIterator.next();
            String internalName = (String) internalIterator.next();
            int firstComparison = internalName.compareTo(foreignName);

            if (0 != firstComparison) {
                return firstComparison;
            }
            String foreignValue = otherAttributeSet.getValue(foreignName);
            String internalValue = getValue(foreignName);
            int secondComparison = internalValue.compareTo(foreignValue);

            if (0 != secondComparison) {
                return secondComparison;
            }
        }
        return 0;
    }
}