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package org.jruby.java.util;

import org.jruby.runtime.builtin.IRubyObject;

import java.util.Collection;
import java.util.Map;
import java.util.Set;

A java.lang.Map that defers all methods to System properties.
/**
 * A java.lang.Map that defers all methods to System properties.
 */
public class SystemPropertiesMap implements Map {

    protected String stringFromObject(Object o) {
        if (o instanceof String) {
            return (String) o;
        }
        if (o instanceof IRubyObject) {
            return ((IRubyObject) o).toJava(String.class);
        }
        return null;
    }

    public int size() {
        return System.getProperties().size();
    }

    public boolean isEmpty() {
        return false;
    }

    public boolean containsKey(Object o) {
        String key = stringFromObject(o);
        if (key != null) {
            return System.getProperty(key) != null;
        }
        return false;
    }

    public boolean containsValue(Object o) {
        String value = stringFromObject(o);
        if (value != null) {
            return System.getProperties().containsValue(value);
        }
        return false;
    }

    public Object get(Object o) {
        String key = stringFromObject(o);
        if (key != null) {
            return System.getProperty(key);
        }
        return null;
    }

    public Object put(Object s, Object s1) {
        String key = stringFromObject(s);
        String value = stringFromObject(s1);
        if (key != null) {
            if (value == null) {
                return System.clearProperty(key);
            }
            return System.setProperty(key, value);
        }
        return null;
    }

    public Object remove(Object o) {
        String key = stringFromObject(o);
        if (key != null) {
            return System.clearProperty(key);
        }
        return null;
    }

    public void putAll(Map map) {
        for (Map.Entry entry : (Set<Entry>) map.entrySet()) {
            String key = stringFromObject(entry.getKey());
            if (key != null) {
                String value = stringFromObject(entry.getValue());
                if (value == null) {
                    System.clearProperty(key);
                } else {
                    System.setProperty(key, value);
                }
            }
        }
    }

    public void clear() {
        // ignored
    }

    public Set<Object> keySet() {
        return System.getProperties().keySet();
    }

    public Collection<Object> values() {
        return System.getProperties().values();
    }

    public Set<Entry<Object, Object>> entrySet() {
        return System.getProperties().entrySet();
    }

}