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Apache Hadoop MapReduce Streaming
/**
* 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.hadoop.typedbytes;
import java.io.ByteArrayInputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.IOException;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.ArrayWritable;
import org.apache.hadoop.io.BooleanWritable;
import org.apache.hadoop.io.ByteWritable;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.FloatWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.MapWritable;
import org.apache.hadoop.io.SortedMapWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.VIntWritable;
import org.apache.hadoop.io.VLongWritable;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.util.ReflectionUtils;
/**
* Provides functionality for reading typed bytes as Writable objects.
*
* @see TypedBytesInput
*/
public class TypedBytesWritableInput implements Configurable {
private TypedBytesInput in;
private Configuration conf;
private TypedBytesWritableInput() {
conf = new Configuration();
}
private void setTypedBytesInput(TypedBytesInput in) {
this.in = in;
}
private static final ThreadLocal TB_IN =
new ThreadLocal() {
@Override
protected TypedBytesWritableInput initialValue() {
return new TypedBytesWritableInput();
}
};
/**
* Get a thread-local typed bytes writable input for the supplied
* {@link TypedBytesInput}.
*
* @param in typed bytes input object
* @return typed bytes writable input corresponding to the supplied
* {@link TypedBytesInput}.
*/
public static TypedBytesWritableInput get(TypedBytesInput in) {
TypedBytesWritableInput bin = TB_IN.get();
bin.setTypedBytesInput(in);
return bin;
}
/**
* Get a thread-local typed bytes writable input for the supplied
* {@link DataInput}.
*
* @param in data input object
* @return typed bytes writable input corresponding to the supplied
* {@link DataInput}.
*/
public static TypedBytesWritableInput get(DataInput in) {
return get(TypedBytesInput.get(in));
}
/** Creates a new instance of TypedBytesWritableInput. */
public TypedBytesWritableInput(TypedBytesInput in) {
this();
this.in = in;
}
/** Creates a new instance of TypedBytesWritableInput. */
public TypedBytesWritableInput(DataInput din) {
this(new TypedBytesInput(din));
}
public Writable read() throws IOException {
Type type = in.readType();
if (type == null) {
return null;
}
switch (type) {
case BYTES:
return readBytes();
case BYTE:
return readByte();
case BOOL:
return readBoolean();
case INT:
return readVInt();
case LONG:
return readVLong();
case FLOAT:
return readFloat();
case DOUBLE:
return readDouble();
case STRING:
return readText();
case VECTOR:
return readArray();
case MAP:
return readMap();
case WRITABLE:
return readWritable();
default:
throw new RuntimeException("unknown type");
}
}
public Class readType() throws IOException {
Type type = in.readType();
if (type == null) {
return null;
}
switch (type) {
case BYTES:
return BytesWritable.class;
case BYTE:
return ByteWritable.class;
case BOOL:
return BooleanWritable.class;
case INT:
return VIntWritable.class;
case LONG:
return VLongWritable.class;
case FLOAT:
return FloatWritable.class;
case DOUBLE:
return DoubleWritable.class;
case STRING:
return Text.class;
case VECTOR:
return ArrayWritable.class;
case MAP:
return MapWritable.class;
case WRITABLE:
return Writable.class;
default:
throw new RuntimeException("unknown type");
}
}
public BytesWritable readBytes(BytesWritable bw) throws IOException {
byte[] bytes = in.readBytes();
if (bw == null) {
bw = new BytesWritable(bytes);
} else {
bw.set(bytes, 0, bytes.length);
}
return bw;
}
public BytesWritable readBytes() throws IOException {
return readBytes(null);
}
public ByteWritable readByte(ByteWritable bw) throws IOException {
if (bw == null) {
bw = new ByteWritable();
}
bw.set(in.readByte());
return bw;
}
public ByteWritable readByte() throws IOException {
return readByte(null);
}
public BooleanWritable readBoolean(BooleanWritable bw) throws IOException {
if (bw == null) {
bw = new BooleanWritable();
}
bw.set(in.readBool());
return bw;
}
public BooleanWritable readBoolean() throws IOException {
return readBoolean(null);
}
public IntWritable readInt(IntWritable iw) throws IOException {
if (iw == null) {
iw = new IntWritable();
}
iw.set(in.readInt());
return iw;
}
public IntWritable readInt() throws IOException {
return readInt(null);
}
public VIntWritable readVInt(VIntWritable iw) throws IOException {
if (iw == null) {
iw = new VIntWritable();
}
iw.set(in.readInt());
return iw;
}
public VIntWritable readVInt() throws IOException {
return readVInt(null);
}
public LongWritable readLong(LongWritable lw) throws IOException {
if (lw == null) {
lw = new LongWritable();
}
lw.set(in.readLong());
return lw;
}
public LongWritable readLong() throws IOException {
return readLong(null);
}
public VLongWritable readVLong(VLongWritable lw) throws IOException {
if (lw == null) {
lw = new VLongWritable();
}
lw.set(in.readLong());
return lw;
}
public VLongWritable readVLong() throws IOException {
return readVLong(null);
}
public FloatWritable readFloat(FloatWritable fw) throws IOException {
if (fw == null) {
fw = new FloatWritable();
}
fw.set(in.readFloat());
return fw;
}
public FloatWritable readFloat() throws IOException {
return readFloat(null);
}
public DoubleWritable readDouble(DoubleWritable dw) throws IOException {
if (dw == null) {
dw = new DoubleWritable();
}
dw.set(in.readDouble());
return dw;
}
public DoubleWritable readDouble() throws IOException {
return readDouble(null);
}
public Text readText(Text t) throws IOException {
if (t == null) {
t = new Text();
}
t.set(in.readString());
return t;
}
public Text readText() throws IOException {
return readText(null);
}
public ArrayWritable readArray(ArrayWritable aw) throws IOException {
if (aw == null) {
aw = new ArrayWritable(TypedBytesWritable.class);
} else if (!aw.getValueClass().equals(TypedBytesWritable.class)) {
throw new RuntimeException("value class has to be TypedBytesWritable");
}
int length = in.readVectorHeader();
Writable[] writables = new Writable[length];
for (int i = 0; i < length; i++) {
writables[i] = new TypedBytesWritable(in.readRaw());
}
aw.set(writables);
return aw;
}
public ArrayWritable readArray() throws IOException {
return readArray(null);
}
public MapWritable readMap(MapWritable mw) throws IOException {
if (mw == null) {
mw = new MapWritable();
}
int length = in.readMapHeader();
for (int i = 0; i < length; i++) {
Writable key = read();
Writable value = read();
mw.put(key, value);
}
return mw;
}
public MapWritable readMap() throws IOException {
return readMap(null);
}
public >
SortedMapWritable readSortedMap(SortedMapWritable mw)
throws IOException {
if (mw == null) {
mw = new SortedMapWritable();
}
int length = in.readMapHeader();
for (int i = 0; i < length; i++) {
@SuppressWarnings("unchecked")
K key = (K) read();
Writable value = read();
mw.put(key, value);
}
return mw;
}
public > SortedMapWritable
readSortedMap() throws IOException {
return readSortedMap((SortedMapWritable)null);
}
public Writable readWritable(Writable writable) throws IOException {
ByteArrayInputStream bais = new ByteArrayInputStream(in.readBytes());
DataInputStream dis = new DataInputStream(bais);
String className = WritableUtils.readString(dis);
if (writable == null) {
try {
Class cls =
conf.getClassByName(className).asSubclass(Writable.class);
writable = (Writable) ReflectionUtils.newInstance(cls, conf);
} catch (ClassNotFoundException e) {
throw new IOException(e);
}
} else if (!writable.getClass().getName().equals(className)) {
throw new IOException("wrong Writable class given");
}
writable.readFields(dis);
return writable;
}
public Writable readWritable() throws IOException {
return readWritable(null);
}
public Configuration getConf() {
return conf;
}
public void setConf(Configuration conf) {
this.conf = conf;
}
}