defaultiofilterchain.java

mina是以Java实现的一个开源的网络程序框架

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 *  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.mina.core.filterchain;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.filterchain.IoFilter.NextFilter;
import org.apache.mina.core.future.ConnectFuture;
import org.apache.mina.core.future.IoFuture;
import org.apache.mina.core.session.AbstractIoSession;
import org.apache.mina.core.session.AttributeKey;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.core.write.WriteRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A default implementation of {@link IoFilterChain} that provides
 * all operations for developers who want to implement their own
 * transport layer once used with {@link AbstractIoSession}.
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 637741 $, $Date: 2008-03-17 07:39:20 +0100 (Mon, 17 Mar 2008) $
 */
public class DefaultIoFilterChain implements IoFilterChain {
    /**
     * A session attribute that stores an {@link IoFuture} related with
     * the {@link IoSession}.  {@link DefaultIoFilterChain} clears this
     * attribute and notifies the future when {@link #fireSessionCreated()}
     * or {@link #fireExceptionCaught(Throwable)} is invoked.
     */
    public static final AttributeKey SESSION_CREATED_FUTURE = new AttributeKey(
            DefaultIoFilterChain.class, "connectFuture");

    /** The associated session */
    private final AbstractIoSession session;

    private final Map<String, Entry> name2entry = new HashMap<String, Entry>();

    /** The chain head */
    private final EntryImpl head;

    /** The chain tail */
    private final EntryImpl tail;

    /** The logger for this class */
    private final Logger logger = LoggerFactory.getLogger(getClass());

    
    /**
     * Create a new default chain, associated with a session. It will only contain a 
     * HeadFilter and a TailFilter.
     * 
     * @param session The session associated with the created filter chain
     */
    public DefaultIoFilterChain(AbstractIoSession session) {
        if (session == null) {
            throw new NullPointerException("session");
        }

        this.session = session;
        head = new EntryImpl(null, null, "head", new HeadFilter());
        tail = new EntryImpl(head, null, "tail", new TailFilter());
        head.nextEntry = tail;
    }

    public IoSession getSession() {
        return session;
    }

    public Entry getEntry(String name) {
        Entry e = name2entry.get(name);
        if (e == null) {
            return null;
        }
        return e;
    }

    public Entry getEntry(IoFilter filter) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (e.getFilter() == filter) {
                return e;
            }
            e = e.nextEntry;
        }
        return null;
    }

    public Entry getEntry(Class<? extends IoFilter> filterType) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (filterType.isAssignableFrom(e.getFilter().getClass())) {
                return e;
            }
            e = e.nextEntry;
        }
        return null;
    }

    public IoFilter get(String name) {
        Entry e = getEntry(name);
        if (e == null) {
            return null;
        }

        return e.getFilter();
    }

    public IoFilter get(Class<? extends IoFilter> filterType) {
        Entry e = getEntry(filterType);
        if (e == null) {
            return null;
        }

        return e.getFilter();
    }

    public NextFilter getNextFilter(String name) {
        Entry e = getEntry(name);
        if (e == null) {
            return null;
        }

        return e.getNextFilter();
    }

    public NextFilter getNextFilter(IoFilter filter) {
        Entry e = getEntry(filter);
        if (e == null) {
            return null;
        }

        return e.getNextFilter();
    }

    public NextFilter getNextFilter(Class<? extends IoFilter> filterType) {
        Entry e = getEntry(filterType);
        if (e == null) {
            return null;
        }

        return e.getNextFilter();
    }

    public synchronized void addFirst(String name, IoFilter filter) {
        checkAddable(name);
        register(head, name, filter);
    }

    public synchronized void addLast(String name, IoFilter filter) {
        checkAddable(name);
        register(tail.prevEntry, name, filter);
    }

    public synchronized void addBefore(String baseName, String name,
            IoFilter filter) {
        EntryImpl baseEntry = checkOldName(baseName);
        checkAddable(name);
        register(baseEntry.prevEntry, name, filter);
    }

    public synchronized void addAfter(String baseName, String name,
            IoFilter filter) {
        EntryImpl baseEntry = checkOldName(baseName);
        checkAddable(name);
        register(baseEntry, name, filter);
    }

    public synchronized IoFilter remove(String name) {
        EntryImpl entry = checkOldName(name);
        deregister(entry);
        return entry.getFilter();
    }

    public synchronized void remove(IoFilter filter) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (e.getFilter() == filter) {
                deregister(e);
                return;
            }
            e = e.nextEntry;
        }
        throw new IllegalArgumentException("Filter not found: "
                + filter.getClass().getName());
    }

    public synchronized IoFilter remove(Class<? extends IoFilter> filterType) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (filterType.isAssignableFrom(e.getFilter().getClass())) {
                IoFilter oldFilter = e.getFilter();
                deregister(e);
                return oldFilter;
            }
            e = e.nextEntry;
        }
        throw new IllegalArgumentException("Filter not found: "
                + filterType.getName());
    }

    public synchronized IoFilter replace(String name, IoFilter newFilter) {
        EntryImpl entry = checkOldName(name);
        IoFilter oldFilter = entry.getFilter();
        entry.setFilter(newFilter);
        return oldFilter;
    }

    public synchronized void replace(IoFilter oldFilter, IoFilter newFilter) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (e.getFilter() == oldFilter) {
                e.setFilter(newFilter);
                return;
            }
            e = e.nextEntry;
        }
        throw new IllegalArgumentException("Filter not found: "
                + oldFilter.getClass().getName());
    }

    public synchronized IoFilter replace(
            Class<? extends IoFilter> oldFilterType, IoFilter newFilter) {
        EntryImpl e = head.nextEntry;
        while (e != tail) {
            if (oldFilterType.isAssignableFrom(e.getFilter().getClass())) {
                IoFilter oldFilter = e.getFilter();
                e.setFilter(newFilter);
                return oldFilter;
            }
            e = e.nextEntry;
        }
        throw new IllegalArgumentException("Filter not found: "
                + oldFilterType.getName());
    }

    public synchronized void clear() throws Exception {
        Iterator<String> it = new ArrayList<String>(name2entry.keySet())
                .iterator();
        while (it.hasNext()) {
            String name = it.next();
            if (contains(name)) {
                remove(name);
            }
        }
    }

    private void register(EntryImpl prevEntry, String name, IoFilter filter) {
        EntryImpl newEntry = new EntryImpl(prevEntry, prevEntry.nextEntry,
                name, filter);

        try {
            filter.onPreAdd(this, name, newEntry.getNextFilter());
        } catch (Exception e) {
            throw new IoFilterLifeCycleException("onPreAdd(): " + name + ':'
                    + filter + " in " + getSession(), e);
        }

        prevEntry.nextEntry.prevEntry = newEntry;
        prevEntry.nextEntry = newEntry;
        name2entry.put(name, newEntry);

        try {
            filter.onPostAdd(this, name, newEntry.getNextFilter());
        } catch (Exception e) {
            deregister0(newEntry);
            throw new IoFilterLifeCycleException("onPostAdd(): " + name + ':'
                    + filter + " in " + getSession(), e);
        }
    }

    private void deregister(EntryImpl entry) {
        IoFilter filter = entry.getFilter();

        try {
            filter.onPreRemove(this, entry.getName(), entry.getNextFilter());
        } catch (Exception e) {
            throw new IoFilterLifeCycleException("onPreRemove(): "
                    + entry.getName() + ':' + filter + " in " + getSession(), e);
        }

        deregister0(entry);

        try {
            filter.onPostRemove(this, entry.getName(), entry.getNextFilter());
        } catch (Exception e) {
            throw new IoFilterLifeCycleException("onPostRemove(): "
                    + entry.getName() + ':' + filter + " in " + getSession(), e);
        }
    }

    private void deregister0(EntryImpl entry) {
        EntryImpl prevEntry = entry.prevEntry;
        EntryImpl nextEntry = entry.nextEntry;
        prevEntry.nextEntry = nextEntry;
        nextEntry.prevEntry = prevEntry;

        name2entry.remove(entry.name);
    }

    /**
     * Throws an exception when the specified filter name is not registered in this chain.
     *
     * @return An filter entry with the specified name.
     */
    private EntryImpl checkOldName(String baseName) {
        EntryImpl e = (EntryImpl) name2entry.get(baseName);
        if (e == null) {
            throw new IllegalArgumentException("Filter not found:" + baseName);
        }
        return e;
    }

    /**
     * Checks the specified filter name is already taken and throws an exception if already taken.
     */
    private void checkAddable(String name) {
        if (name2entry.containsKey(name)) {
            throw new IllegalArgumentException(
                    "Other filter is using the same name '" + name + "'");
        }
    }

    public void fireSessionCreated() {
        Entry head = this.head;
        callNextSessionCreated(head, session);
    }

    private void callNextSessionCreated(Entry entry, IoSession session) {
        try {
            IoFilter filter = entry.getFilter();
            NextFilter nextFilter = entry.getNextFilter();
            filter.sessionCreated(nextFilter, session);
        } catch (Throwable e) {
            fireExceptionCaught(e);
        }
    }

    public void fireSessionOpened() {
        Entry head = this.head;
        callNextSessionOpened(head, session);
    }

    private void callNextSessionOpened(Entry entry, IoSession session) {
        try {
            IoFilter filter = entry.getFilter();
            NextFilter nextFilter = entry.getNextFilter();
            filter.sessionOpened(nextFilter, session);
        } catch (Throwable e) {
            fireExceptionCaught(e);
        }
    }

    public void fireSessionClosed() {
        // Update future.
        try {
            session.getCloseFuture().setClosed();
        } catch (Throwable t) {
            fireExceptionCaught(t);
        }

        // And start the chain.
        Entry head = this.head;
        callNextSessionClosed(head, session);
    }

    private void callNextSessionClosed(Entry entry, IoSession session) {
        try {
            IoFilter filter = entry.getFilter();
            NextFilter nextFilter = entry.getNextFilter();
            filter.sessionClosed(nextFilter, session);
        } catch (Throwable e) {
            fireExceptionCaught(e);
        }
    }

    public void fireSessionIdle(IdleStatus status) {
        session.increaseIdleCount(status, System.currentTimeMillis());
        Entry head = this.head;
        callNextSessionIdle(head, session, status);
    }

    private void callNextSessionIdle(Entry entry, IoSession session,
            IdleStatus status) {
        try {
            IoFilter filter = entry.getFilter();
            NextFilter nextFilter = entry.getNextFilter();
            filter.sessionIdle(nextFilter, session,
                    status);
        } catch (Throwable e) {
            fireExceptionCaught(e);
        }
    }

    public void fireMessageReceived(Object message) {
        if (message instanceof IoBuffer) {
            session.increaseReadBytes(((IoBuffer) message).remaining(), System
                    .currentTimeMillis());
        }

        Entry head = this.head;
        callNextMessageReceived(head, session, message);
    }

    private void callNextMessageReceived(Entry entry, IoSession session,
            Object message) {
        try {
            IoFilter filter = entry.getFilter();
            NextFilter nextFilter = entry.getNextFilter();
            filter.messageReceived(nextFilter, session,
                    message);
        } catch (Throwable e) {
            fireExceptionCaught(e);
        }
    }

    public void fireMessageSent(WriteRequest request) {
        session.increaseWrittenMessages(request, System.currentTimeMillis());

        try {
            request.getFuture().setWritten();
        } catch (Throwable t) {
            fireExceptionCaught(t);
        }