org.apache.commons.chain.impl.CatalogBase Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.commons.chain.impl;
import java.util.HashMap;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.chain.Catalog;
import org.apache.commons.chain.Command;
/**
* Simple in-memory implementation of {@link Catalog}. This class can
* also be used as the basis for more advanced implementations.
*
* This implementation is thread-safe.
*
* @author Craig R. McClanahan
* @author Matthew J. Sgarlata
* @version $Revision: 480477 $ $Date: 2006-11-29 08:34:52 +0000 (Wed, 29 Nov 2006) $
*/
public class CatalogBase implements Catalog {
// ----------------------------------------------------- Instance Variables
/**
* The map of named {@link Command}s, keyed by name.
*/
protected Map commands = Collections.synchronizedMap(new HashMap());
// --------------------------------------------------------- Constructors
/**
* Create an empty catalog.
*/
public CatalogBase() { }
/**
*
Create a catalog whose commands are those specified in the given Map.
* All Map keys should be String and all values should be Command.
*
* @param commands Map of Commands.
*
* @since Chain 1.1
*/
public CatalogBase( Map commands ) {
this.commands = Collections.synchronizedMap(commands);
}
// --------------------------------------------------------- Public Methods
/**
* Add a new name and associated {@link Command}
* to the set of named commands known to this {@link Catalog},
* replacing any previous command for that name.
*
* @param name Name of the new command
* @param command {@link Command} to be returned
* for later lookups on this name
*/
public void addCommand(String name, Command command) {
commands.put(name, command);
}
/**
*
Return the {@link Command} associated with the
* specified name, if any; otherwise, return null.
*
* @param name Name for which a {@link Command}
* should be retrieved
* @return The Command associated with the specified name.
*/
public Command getCommand(String name) {
return ((Command) commands.get(name));
}
/**
* Return an Iterator over the set of named commands
* known to this {@link Catalog}. If there are no known commands,
* an empty Iterator is returned.
* @return An iterator of the names in this Catalog.
*/
public Iterator getNames() {
return (commands.keySet().iterator());
}
/**
* Converts this Catalog to a String. Useful for debugging purposes.
* @return a representation of this catalog as a String
*/
public String toString() {
Iterator names = getNames();
StringBuffer str =
new StringBuffer("[" + this.getClass().getName() + ": ");
while (names.hasNext()) {
str.append(names.next());
if (names.hasNext()) {
str.append(", ");
}
}
str.append("]");
return str.toString();
}
}