cachesizes.java

JSP聊天系统

package org.ehotsoft.yekki.util.cache;

import java.util.Properties;
import java.util.Properties;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;

public class CacheSizes {

    public static int sizeOfObject() {
        return 4;
    }

    public static int sizeOfString(String string) {
        if (string == null) {
            return 0;
        }
        return 4 + string.length()*2;
    }
	
	public static int sizeOfInt() {
        return 4;
    }

    public static int sizeOfChar() {
        return 2;
    }

	public static int sizeOfBoolean() {
        return 1;
    }

    public static int sizeOfLong() {
        return 8;
    }

    public static int sizeOfDouble() {
        return 8;
    }

    public static int sizeOfDate() {
        return 12;
    }

    public static int sizeOfProperties( Properties properties) {
        if ( properties == null ) {
            return 0;
        }
        //Base properties object
        int size = 36;
        //Add in size of each property
        Enumeration enum = properties.elements();
        while( enum.hasMoreElements() ) {
            String prop = ( String )enum.nextElement();
            size += sizeOfString( prop );
        }
        //Add in property names
        enum = properties.propertyNames();
        while( enum.hasMoreElements() ) {
            String prop = ( String )enum.nextElement();
            size += sizeOfString( prop );
        }
        return size;
    }

    public static int sizeOfMap( Map map ) {
        if ( map == null ) {
            return 0;
        }
        //Base map object -- should be something around this size.
        int size = 36;
        //Add in size of each value
        Iterator iter = map.values().iterator();
        while( iter.hasNext() ) {
            String value = ( String )iter.next();
            size += sizeOfString( value );
        }
        //Add in each key
        iter = map.keySet().iterator();
        while( iter.hasNext() ) {
            String key = ( String )iter.next();
            size += sizeOfString( key );
        }
        return size;
    }
}