MidiDispatcher.java

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/*
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 * Copyright (C) 2015 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.example.android.common.midi;
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import android.media.midi.MidiReceiver;
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import android.media.midi.MidiSender;
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import java.io.IOException;
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import java.util.concurrent.CopyOnWriteArrayList;
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/**
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 * Utility class for dispatching MIDI data to a list of {@link MidiReceiver}s.
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 * This class subclasses {@link MidiReceiver} and dispatches any data it receives
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 * to its receiver list. Any receivers that throw an exception upon receiving data will
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 * be automatically removed from the receiver list, but no IOException will be returned
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 * from the dispatcher's {@link MidiReceiver#onReceive} in that case.
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 */
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public final class MidiDispatcher extends MidiReceiver {
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    private final CopyOnWriteArrayList<MidiReceiver> mReceivers
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            = new CopyOnWriteArrayList<MidiReceiver>();
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    private final MidiSender mSender = new MidiSender() {
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        /**
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         * Called to connect a {@link MidiReceiver} to the sender
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         *
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         * @param receiver the receiver to connect
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         */
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        @Override
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        public void onConnect(MidiReceiver receiver) {
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            mReceivers.add(receiver);
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        }
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        /**
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         * Called to disconnect a {@link MidiReceiver} from the sender
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         *
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         * @param receiver the receiver to disconnect
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         */
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        @Override
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        public void onDisconnect(MidiReceiver receiver) {
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            mReceivers.remove(receiver);
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        }
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    };
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    /**
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     * Returns the number of {@link MidiReceiver}s this dispatcher contains.
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     * @return the number of receivers
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     */
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    public int getReceiverCount() {
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        return mReceivers.size();
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    }
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    /**
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     * Returns a {@link MidiSender} which is used to add and remove
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     * {@link MidiReceiver}s
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     * to the dispatcher's receiver list.
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     * @return the dispatcher's MidiSender
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     */
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    public MidiSender getSender() {
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        return mSender;
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    }
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    @Override
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    public void onSend(byte[] msg, int offset, int count, long timestamp) throws IOException {
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       for (MidiReceiver receiver : mReceivers) {
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            try {
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                receiver.send(msg, offset, count, timestamp);
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            } catch (IOException e) {
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                // if the receiver fails we remove the receiver but do not propagate the exception
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                mReceivers.remove(receiver);
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            }
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        }
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    }
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    @Override
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    public void flush() throws IOException {
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       for (MidiReceiver receiver : mReceivers) {
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            receiver.flush();
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       }
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    }
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}
Mar	APR	May
	03
2015	2016	2017
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MidiDispatcher.java
