jndiconfiguration.java

java servlet著名论坛源代码

package net.myvietnam.mvncore.configuration;
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 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
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import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Properties;
import java.util.Vector;
import javax.naming.Binding;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
 * This Configuration class allows you to interface with a JNDI datasource.
 *
 * @author <a href="mailto:[e-mail]">Eric Pugh</a>
 * @version $Id: JNDIConfiguration.java,v 1.2 2004/05/28 22:02:58 skoehler Exp $
 */
public class JNDIConfiguration
    extends BaseConfiguration
    implements Configuration
{
    private static Log log = LogFactory.getLog(JNDIConfiguration.class);
    private String prefix;
    private Context envCtx;
    private List clearedProperties = new ArrayList();
    /**
     * Creates an empty JNDIConfiguration object which can then
     * be added some other Configuration files
     */
    public JNDIConfiguration()
    {
    }
    /**
     * JNDIConfigurations can not be added to
     *
     * @param key The Key to add the property to.
     * @param token The Value to add.
     */
    public void addProperty(String key, Object token)
    {
        throw new Error("This operation is not supported");
    }
    /**
     * This method recursive traverse the JNDI tree, looking for Context objects.
     * When it finds them, it traverses them as well.  Otherwise it just adds the
     * values to the list of keys found.
     * @param keys All the keys that have been found.
     * @param enum An enumeration of all the elements found at a specific context
     * @param key What key we are building on.
     * @throws NamingException If JNDI has an issue.
     */
    private void recursiveGetKeys(
        List keys,
        NamingEnumeration enum,
        String key)
        throws NamingException
    {
        while (enum.hasMoreElements())
        {
            Binding binding = (Binding) enum.next();
            StringBuffer newKey = new StringBuffer();
            newKey.append(key);
            if (newKey.length() > 0)
            {
                newKey.append(".");
            }
            newKey.append(binding.getName());
            if (binding.getObject() instanceof Context)
            {
                Context c = (Context) binding.getObject();
                NamingEnumeration enum2 = c.listBindings("");
                recursiveGetKeys(keys, enum2, newKey.toString());
            }
            else
            {
                if (!keys.contains(newKey.toString()))
                {
                    keys.add(newKey.toString());
                }
            }
        }
    }
    /**
     * Get the list of the keys contained in the configuration
     * repository.
     *
     * @return An Iterator.
     */
    public Iterator getKeys()
    {
        return getKeys("");
    }
    /**
     * Get the list of the keys contained in the configuration
     * repository that match a passed in beginning pattern.
     *
     * @param key the key pattern to match on.
     * @return An Iterator.
     */
    public Iterator getKeys(String key)
    {
        List keys = new ArrayList();
        try
        {
            String[] splitKeys = StringUtils.split(key, ".");
            for (int i = 0; i < splitKeys.length; i++)
            {
                keys.add(splitKeys[i]);
            }
            Context context = null;
            if (keys.size() == 0)
            {
                context = getContext();
            }
            else
            {
                context =
                    getStartingContextPoint(
                        keys,
                        getContext().listBindings(""));
            }
            if (context != null)
            {
                NamingEnumeration enum = context.listBindings("");
                recursiveGetKeys(keys, enum, key);
            }
        }
        catch (NamingException ne)
        {
            log.warn(ne);
        }
        return keys.iterator();
    }
    /**
     * Because JNDI is based on a tree configuration, we need to filter down the
     * tree, till we find the Context specified by the key to start from.
     * Otherwise return null.
     *
     * @param The key (or name) of the Context we are looking to start from.
     * @return The context at that key's location in the JNDI tree, or null if not found
     * @throws NamingException if JNDI has an issue
     */
    private Context getStartingContextPoint(List keys, NamingEnumeration enum)
        throws NamingException
    {
        String keyToSearchFor = (String) keys.get(0);
        log.debug("Key to search for is " + keyToSearchFor);
        while (enum.hasMoreElements())
        {
            Binding binding = (Binding) enum.next();
            log.debug(
                "Binding for name: "
                    + binding.getName()
                    + ", object:"
                    + binding.getObject()
                    + ", class:"
                    + binding.getClassName());
            if (binding.getObject() instanceof Context
                && binding.getName().equals(keyToSearchFor))
            {
                keys.remove(0);
                Context c = (Context) binding.getObject();
                if (keys.size() > 0)
                {
                    return getStartingContextPoint(keys, c.listBindings(""));
                }
                else
                {
                    return c;
                }
            }
        }
        return null;
    }
    /**
     * Get a list of properties associated with the given
     * configuration key.
     *
     * @param key The configuration key.
     * @return The associated properties if key is found.
     * @throws ClassCastException is thrown if the key maps to an
     * object that is not a String/Vector.
     * @throws IllegalArgumentException if one of the tokens is
     * malformed (does not contain an equals sign).
     * @see #getProperties(String, Properties)
     */
    public Properties getProperties(String key)
    {
        throw new Error("This operation is not supported");
    }
    public boolean isEmpty()
    {
        try
        {
            NamingEnumeration enum = getContext().listBindings("");
            return !enum.hasMore();
        }
        catch (NamingException ne)
        {
            log.warn(ne);
            return true;
        }
    }
    /**
     *  Gets a property from the configuration.
     *
     *  @param key property to retrieve
     *  @return value as object. Will return user value if exists,
     *          if not then default value if exists, otherwise null
     */
    public Object getProperty(String key)
    {
        throw new Error("This operation is not supported");
    }
    /**
     * Set a property, this will replace any previously
     * set values. Set values is implicitly a call
     * to clearProperty(key), addProperty(key,value).
     *
     * @param key
     * @param value
     */
    public void setProperty(String key, Object value)
    {
        throw new Error("This operation is not supported");
    }
    /**
     * Clear a property in the configuration.  Just marks it as cleared,
     * doesn't change the underlying JNDI data source.
     *
     * @param key the key to remove along with corresponding value.
     */
    public void clearProperty(String key)
    {
        if (!clearedProperties.contains(key))
        {
            clearedProperties.add(key);
        }
    }
    /**
     * check if the configuration contains the key, or the key
     * has been removed.
     */
    public boolean containsKey(String key)
    {
        if (clearedProperties.contains(key))
        {
            return false;
        }
        key = StringUtils.replace(key, ".", "/");
        try
        {
        	// throws a NamingException if JNDI doesn't contain the key.
            getContext().lookup(key);
            return true;
        }
        catch (javax.naming.NamingException ne)
        {
            return false;
        }
    }
    /**
     * Create an ExtendedProperties object that is a subset
     * of this one. Take into account duplicate keys
     * by using the setProperty() in ExtendedProperties.
     *
     * @param prefix
     */
    public Configuration subset(String prefix)
    {
        BaseConfiguration c = new BaseConfiguration();
        Iterator keys = this.getKeys();
        boolean validSubset = false;
        while (keys.hasNext())
        {
            Object key = keys.next();
            if (key instanceof String && ((String) key).startsWith(prefix))
            {
                if (!validSubset)
                {
                    validSubset = true;
                }
                String newKey = null;
                /*
                 * Check to make sure that c.subset(prefix) doesn't blow up when
                 * there is only a single property with the key prefix. This is
                 * not a useful subset but it is a valid subset.
                 */
                if (((String) key).length() == prefix.length())
                {
                    newKey = prefix;
                }
                else
                {
                    newKey = ((String) key).substring(prefix.length() + 1);
                }
                /*
                 * use addPropertyDirect() - this will plug the data as is into
                 * the Map, but will also do the right thing re key accounting
                 */
                Object value = getValueFromJNDI(key.toString());
                if (value instanceof String)
                {
                    c.addPropertyDirect(newKey, interpolate((String) value));
                }
                else
                {
                    c.addPropertyDirect(newKey, value);
                }
            }
        }
        if (validSubset)
        {
            return c;
        }
        else
        {
            return null;
        }
    }

    /**
     * Get a boolean associated with the given configuration key.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated boolean if key is found and has valid
     * format, default value otherwise.
     * @throws ClassCastException is thrown if the key maps to an
     * object that is not a Boolean.