/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.shell.alias.def;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import org.jnode.plugin.ConfigurationElement;
import org.jnode.plugin.Extension;
import org.jnode.plugin.ExtensionPoint;
import org.jnode.plugin.ExtensionPointListener;
import org.jnode.shell.alias.AliasManager;
import org.jnode.shell.alias.NoSuchAliasException;
import org.jnode.util.BooleanUtils;
/**
* @author epr
*/
public class DefaultAliasManager implements AliasManager,
ExtensionPointListener {
private final DefaultAliasManager parent;
private final HashMap<String, Alias> aliases = new HashMap<String, Alias>();
private final ExtensionPoint aliasesEP;
/**
* Create a new instance
*/
public DefaultAliasManager(ExtensionPoint aliasesEP) {
this.parent = null;
this.aliasesEP = aliasesEP;
aliasesEP.addListener(this);
refreshAliases();
}
/**
* Create a new instance
*/
public DefaultAliasManager(DefaultAliasManager parent) {
this.parent = parent;
this.aliasesEP = null;
if (parent == null) {
throw new IllegalArgumentException("parent cannot be null");
}
}
/**
* Add an alias
*
* @param alias
* @param className
*/
public void add(String alias, String className) {
if (parent == null) {
throw new UnsupportedOperationException(
"Cannot modify the system alias manager");
} else {
aliases.put(alias, new Alias(alias, className, false));
}
}
/**
* Remove an alias
*
* @param alias
*/
public void remove(String alias) {
if (parent == null) {
throw new UnsupportedOperationException(
"Cannot modify the system alias manager");
} else {
aliases.remove(alias);
}
}
/**
* Gets the class of a given alias
*
* @param alias
* @return the class of the given alias
* @throws ClassNotFoundException
*/
public Class<?> getAliasClass(String alias) throws ClassNotFoundException,
NoSuchAliasException {
return getAlias(alias).getAliasClass();
}
/**
* Should the given alias be invoked in the context of the shell, instead of
* in its own context.
*
* @param alias
*/
public boolean isInternal(String alias) throws NoSuchAliasException {
return getAlias(alias).isInternal();
}
/**
* Gets the class name of a given alias
*
* @param alias
* @return the class name of the given alias
*/
public String getAliasClassName(String alias) throws NoSuchAliasException {
return getAlias(alias).getClassName();
}
/**
* Create a new alias manager that has this alias manager as parent.
*/
public AliasManager createAliasManager() {
return new DefaultAliasManager(this);
}
/**
* Gets a collection of all aliases.
*/
public Collection<String> aliases() {
if (parent == null) {
return Collections.unmodifiableCollection(aliases.keySet());
} else {
final HashSet<String> all = new HashSet<String>();
all.addAll(parent.aliases());
all.addAll(aliases.keySet());
return all;
}
}
/**
* Gets an iterator to iterator over all aliases.
*
* @return An iterator the returns instances of String.
*/
public Iterator<String> aliasIterator() {
return aliases().iterator();
}
/**
* Gets the alias with the given name
*
* @param alias
*/
protected Alias getAlias(String alias) throws NoSuchAliasException {
final Alias a = (Alias) aliases.get(alias);
if (a != null) {
return a;
} else if (parent != null) {
return parent.getAlias(alias);
} else {
throw new NoSuchAliasException(alias);
}
}
/**
* Reload the alias list from the extension-point
*/
protected void refreshAliases() {
System.out.println("Refreshing alias list");
if (aliasesEP != null) {
aliases.clear();
final Extension[] extensions = aliasesEP.getExtensions();
for (int i = 0; i < extensions.length; i++) {
final Extension ext = extensions[i];
final ConfigurationElement[] elements = ext
.getConfigurationElements();
for (int j = 0; j < elements.length; j++) {
createAlias(aliases, elements[j]);
}
}
}
}
private void createAlias(Map<String, Alias> aliases, ConfigurationElement element) {
final String name = element.getAttribute("name");
final String className = element.getAttribute("class");
final boolean internal = BooleanUtils.valueOf(element
.getAttribute("internal"));
if ((name != null) && (className != null)) {
aliases.put(name, new Alias(name, className, internal));
}
}
/**
* @see org.jnode.plugin.ExtensionPointListener#extensionAdded(org.jnode.plugin.ExtensionPoint,
* org.jnode.plugin.Extension)
*/
public void extensionAdded(ExtensionPoint point, Extension extension) {
refreshAliases();
}
/**
* @see org.jnode.plugin.ExtensionPointListener#extensionRemoved(org.jnode.plugin.ExtensionPoint,
* org.jnode.plugin.Extension)
*/
public void extensionRemoved(ExtensionPoint point, Extension extension) {
refreshAliases();
}
static class Alias {
private final String alias;
private final String className;
private Class<?> aliasClass;
private final boolean internal;
public Alias(String alias, String className, boolean internal) {
this.alias = alias;
this.className = className;
this.internal = internal;
}
/**
* Gets the name of this alias
*/
public String getAlias() {
return alias;
}
/**
* Gets the name of the class of this alias
*/
public String getClassName() {
return className;
}
/**
* Gets the class of this alias
*/
public Class<?> getAliasClass() throws ClassNotFoundException {
if (aliasClass == null) {
aliasClass = Thread.currentThread().getContextClassLoader()
.loadClass(className);
}
return aliasClass;
}
/**
* Should this alias be executed in the context of the shell, instead of
* in its own context.
*
* @return
*/
public final boolean isInternal() {
return internal;
}
}
}