/*
 * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/params/DefaultHttpParams.java,v 1.8 2004/05/13 04:01:22 mbecke Exp $
 * $Revision: 1.8 $
 * $Date: 2004/05/13 04:01:22 $
 *
 * ====================================================================
 *
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient.params;

import java.io.Serializable;
import java.util.HashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This class represents a collection of HTTP protocol parameters. Protocol parameters
 * may be linked together to form a hierarchy. If a particular parameter value has not been
 * explicitly defined in the collection itself, its value will be drawn from the parent 
 * collection of parameters.
 * 
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 * 
 * @version $Revision: 1.8 $
 * 
 * @since 3.0
 */
public class DefaultHttpParams implements HttpParams, Serializable, Cloneable {

    /** Log object for this class. */
    private static final Log LOG = LogFactory.getLog(DefaultHttpParams.class);

    /** HttpParams class factory. */
    private static HttpParamsFactory httpParamsFactory = new DefaultHttpParamsFactory();

    /**
     * Gets the default HttpParams to be used.
     * 
     * @return the value returned from <code>HttpParamsFactory#getDefaultParams()</code>
     * 
     * @see HttpParamsFactory#getDefaultParams()
     */
    public static HttpParams getDefaultParams() {
        return httpParamsFactory.getDefaultParams();
    }
    
    /**
     * Sets the factory that will provide the default HttpParams.
     * 
     * @param httpParamsFactory an instance of HttpParamsFactory
     * 
     * @see #getDefaultParams()
     */
    public static void setHttpParamsFactory(HttpParamsFactory httpParamsFactory) {
        if (httpParamsFactory == null) {
            throw new IllegalArgumentException("httpParamsFactory may not be null");
        }
        DefaultHttpParams.httpParamsFactory = httpParamsFactory;
    }

    /** The set of default values to defer to */
    private HttpParams defaults = null;

    /** Hash map of HTTP parameters that this collection contains */
    private HashMap parameters = null;
    
    /**
     * Creates a new collection of parameters with the given parent. 
     * The collection will defer to its parent for a default value 
     * if a particular parameter is not explicitly set in the collection
     * itself.
     * 
     * @param defaults the parent collection to defer to, if a parameter
     * is not explictly set in the collection itself.
     */
    public DefaultHttpParams(final HttpParams defaults) {
        super();
        this.defaults = defaults; 
    }
    
    /**
     * Creates a new collection of parameters with the collection returned
     * by {@link #getDefaultParams()} as a parent. The collection will defer
     * to its parent for a default value if a particular parameter is not 
     * explicitly set in the collection itself.
     * 
     * @see #getDefaultParams()
     */
    public DefaultHttpParams() {
        this(getDefaultParams());
    }
    
    public synchronized HttpParams getDefaults() {
        return this.defaults;
    }
    
    public synchronized void setDefaults(final HttpParams params) {
        this.defaults = params;
    }
    
    public synchronized Object getParameter(final String name) {
        // See if the parameter has been explicitly defined
        Object param = null;
        if (this.parameters != null) {
            param = this.parameters.get(name);
        }    
        if (param != null) {
            // If so, return
            return param;
        } else {
            // If not, see if defaults are available
            if (this.defaults != null) {
                // Return default parameter value
                return this.defaults.getParameter(name);
            } else {
                // Otherwise, return null
                return null;
            }
        }
    }

    public synchronized void setParameter(final String name, final Object value) {
        if (this.parameters == null) {
            this.parameters = new HashMap();
        }
        this.parameters.put(name, value);
        if (LOG.isDebugEnabled()) {
            LOG.debug("Set parameter " + name + " = " + value.toString());
        }
    }
    
    /**
     * Assigns the value to all the parameter with the given names
     * 
     * @param names array of parameter name
     * @param value parameter value
     */ 
    public synchronized void setParameters(final String[] names, final Object value) {
        for (int i = 0; i < names.length; i++) {
            setParameter(names[i], value);
        }
    }

    public long getLongParameter(final String name, long defaultValue) { 
        Object param = getParameter(name);
        if (param == null) {
            return defaultValue;
        }
        return ((Long)param).longValue();
    }
    
    public void setLongParameter(final String name, long value) {
        setParameter(name, new Long(value));
    }

    public int getIntParameter(final String name, int defaultValue) { 
        Object param = getParameter(name);
        if (param == null) {
            return defaultValue;
        }
        return ((Integer)param).intValue();
    }
    
    public void setIntParameter(final String name, int value) {
        setParameter(name, new Integer(value));
    }

    public double getDoubleParameter(final String name, double defaultValue) { 
        Object param = getParameter(name);
        if (param == null) {
            return defaultValue;
        }
        return ((Double)param).doubleValue();
    }
    
    public void setDoubleParameter(final String name, double value) {
        setParameter(name, new Double(value));
    }

    public boolean getBooleanParameter(final String name, boolean defaultValue) { 
        Object param = getParameter(name);
        if (param == null) {
            return defaultValue;
        }
        return ((Boolean)param).booleanValue();
    }
    
    public void setBooleanParameter(final String name, boolean value) {
        setParameter(name, new Boolean(value));
    }

    public boolean isParameterSet(final String name) {
        return getParameter(name) != null;
    }
        
    public boolean isParameterSetLocally(final String name) {
        return this.parameters != null && this.parameters.get(name) != null;
    }
        
    public boolean isParameterTrue(final String name) {
        return getBooleanParameter(name, false);
    }
        
    public boolean isParameterFalse(final String name) {
        return !getBooleanParameter(name, false);
    }

    /**
     * Removes all parameters from this collection. 
     */
    public void clear() {
        this.parameters = null;
    }

    /**
     * Clones this collection of parameters. Please note that paramter values
     * themselves are not cloned. 
     * 
     * @see java.io.Serializable
     * @see java.lang.Object#clone()
     */
    public Object clone() throws CloneNotSupportedException
    {
        DefaultHttpParams clone = (DefaultHttpParams)super.clone();
        if (this.parameters != null) {
            clone.parameters = (HashMap)this.parameters.clone(); 
        }
        clone.setDefaults(this.defaults);
        return clone;
    }
}