/*
* Copyright 2017 NAVER Corp.
*
* Licensed 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 com.navercorp.pinpoint.common.server.bo.codec.stat.strategy;
import com.navercorp.pinpoint.common.Charsets;
import com.navercorp.pinpoint.common.buffer.Buffer;
import com.navercorp.pinpoint.common.server.bo.codec.StringTypedBufferHandler;
import com.navercorp.pinpoint.common.server.bo.codec.strategy.EncodingStrategy;
import com.navercorp.pinpoint.common.server.bo.codec.strategy.impl.StringAlwaysSameValueEncodingStrategy;
import com.navercorp.pinpoint.common.server.bo.codec.strategy.impl.StringRepeatCountEncodingStrategy;
import com.navercorp.pinpoint.common.server.bo.codec.strategy.impl.StringValueEncodingStrategy;
import com.navercorp.pinpoint.common.util.BytesUtils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
/**
* @author Taejin Koo
*/
public enum StringEncodingStrategy implements EncodingStrategy<String> {
NONE(new StringValueEncodingStrategy(StringTypedBufferHandler.VARIABLE_HANDLER)),
REPEAT_COUNT(new StringRepeatCountEncodingStrategy(StringTypedBufferHandler.VARIABLE_HANDLER)),
ALWAYS_SAME_VALUE(new StringAlwaysSameValueEncodingStrategy(StringTypedBufferHandler.VARIABLE_HANDLER));
private final EncodingStrategy<String> delegate;
StringEncodingStrategy(EncodingStrategy<String> delegate) {
this.delegate = delegate;
}
@Override
public byte getCode() {
return this.delegate.getCode();
}
@Override
public void encodeValues(Buffer buffer, List<String> values) {
this.delegate.encodeValues(buffer, values);
}
@Override
public List<String> decodeValues(Buffer buffer, int numValues) {
return this.delegate.decodeValues(buffer, numValues);
}
public static StringEncodingStrategy getFromCode(int code) {
for (StringEncodingStrategy encodingStrategy : StringEncodingStrategy.values()) {
if (encodingStrategy.getCode() == (code & 0xFF)) {
return encodingStrategy;
}
}
throw new IllegalArgumentException("Unknown code : " + code);
}
public static class Analyzer implements StrategyAnalyzer<String> {
private final EncodingStrategy<String> bestStrategy;
private final List<String> values;
private Analyzer(EncodingStrategy<String> bestStrategy, List<String> values) {
this.bestStrategy = bestStrategy;
this.values = values;
}
@Override
public EncodingStrategy<String> getBestStrategy() {
return this.bestStrategy;
}
@Override
public List<String> getValues() {
return this.values;
}
public static class Builder implements StrategyAnalyzerBuilder<String> {
private static final int MAX_BYTES_PER_CHAR_UTF8 = (int) Charsets.UTF_8.newEncoder().maxBytesPerChar();
private final List<String> values = new ArrayList<String>();
private String previousValue = null;
private int byteSizeValue = 0;
private int repeatedValueCount = 0;
private int byteSizeRepeatCount = 0;
@Override
public StrategyAnalyzerBuilder<String> addValue(String value) {
if (this.values.isEmpty()) {
initializeByteSizes(value);
} else {
updateByteSizes(value);
}
this.previousValue = value;
this.values.add(value);
return this;
}
@Override
public StrategyAnalyzer<String> build() {
if (this.repeatedValueCount > 0) {
this.byteSizeRepeatCount += BytesUtils.computeVar32Size(this.repeatedValueCount);
}
EncodingStrategy<String> bestStrategy;
if (repeatedValueCount != 0 && repeatedValueCount == values.size()) {
bestStrategy = ALWAYS_SAME_VALUE;
} else {
int minimumNumBytesUsed = Collections.min(Arrays.asList(
this.byteSizeValue,
this.byteSizeRepeatCount));
if (this.byteSizeValue == minimumNumBytesUsed) {
bestStrategy = NONE;
} else {
bestStrategy = REPEAT_COUNT;
}
}
List<String> values = new ArrayList<String>(this.values);
this.values.clear();
return new Analyzer(bestStrategy, values);
}
private void initializeByteSizes(String value) {
int maxBytesUsedByValue = getMaxBytes(value);
this.byteSizeValue = maxBytesUsedByValue;
this.repeatedValueCount = 1;
this.byteSizeRepeatCount = maxBytesUsedByValue;
}
private void updateByteSizes(String value) {
int maxBytesUsedByValue = getMaxBytes(value);
this.byteSizeValue += maxBytesUsedByValue;
// for null
if (this.previousValue == null) {
if (value == null) {
this.repeatedValueCount++;
} else {
this.byteSizeRepeatCount += expectedBytesVLength(this.repeatedValueCount);
this.byteSizeRepeatCount += maxBytesUsedByValue;
this.repeatedValueCount = 1;
}
} else if (this.previousValue.equals(value)) {
this.repeatedValueCount++;
} else {
this.byteSizeRepeatCount += expectedBytesVLength(this.repeatedValueCount);
this.byteSizeRepeatCount += maxBytesUsedByValue;
this.repeatedValueCount = 1;
}
}
private int getMaxBytes(String value) {
if (value == null) {
return 0;
}
return value.length() * MAX_BYTES_PER_CHAR_UTF8;
}
private int expectedBytesVLength(int value) {
if (value < 0) {
return BytesUtils.computeVar64Size(value);
} else {
return BytesUtils.computeVar32Size(value);
}
}
}
}
}