Github user QiangCai commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2628#discussion_r213922415
--- Diff:
core/src/main/java/org/apache/carbondata/core/datastore/compression/CompressorFactory.java
---
@@ -17,42 +17,99 @@
package org.apache.carbondata.core.datastore.compression;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
import org.apache.carbondata.core.constants.CarbonCommonConstants;
import org.apache.carbondata.core.util.CarbonProperties;
+import org.apache.carbondata.format.CompressionCodec;
public class CompressorFactory {
-
private static final CompressorFactory COMPRESSOR_FACTORY = new
CompressorFactory();
- private final Compressor snappyCompressor;
+ private final Map<String, SupportedCompressor> compressors = new
HashMap<>();
+
+ public enum SupportedCompressor {
+ SNAPPY(CompressionCodec.SNAPPY, "snappy", SnappyCompressor.class),
+ ZSTD(CompressionCodec.ZSTD, "zstd", ZstdCompressor.class);
+
+ private CompressionCodec codec;
+ private String name;
+ private Class<Compressor> compressorClass;
+ private transient Compressor compressor;
+
+ SupportedCompressor(CompressionCodec codec, String name, Class
compressorCls) {
+ this.codec = codec;
+ this.name = name;
+ this.compressorClass = compressorCls;
+ }
+
+ public CompressionCodec getCodec() {
+ return codec;
+ }
+
+ public String getName() {
+ return name;
+ }
+
+ /**
+ * we will load the compressor only if it is needed
+ */
+ public Compressor getCompressor() {
+ if (this.compressor == null) {
+ try {
+ this.compressor = compressorClass.newInstance();
+ } catch (InstantiationException | IllegalAccessException e) {
+ throw new RuntimeException("Exception occurs while getting
compressor for " + name);
+ }
+ }
+ return this.compressor;
+ }
+ }
private CompressorFactory() {
- String compressorType = CarbonProperties.getInstance()
- .getProperty(CarbonCommonConstants.COMPRESSOR,
CarbonCommonConstants.DEFAULT_COMPRESSOR);
- switch (compressorType) {
- case "snappy":
- snappyCompressor = new SnappyCompressor();
- break;
- default:
- throw new RuntimeException(
- "Invalid compressor type provided! Please provide valid
compressor type");
+ for (SupportedCompressor supportedCompressor :
SupportedCompressor.values()) {
+ compressors.put(supportedCompressor.getName(), supportedCompressor);
}
}
public static CompressorFactory getInstance() {
return COMPRESSOR_FACTORY;
}
+ /**
+ * get the default compressor.
+ * This method can only be called in data load procedure to compress
column page.
+ * In query procedure, we should read the compressor information from
the metadata
+ * in datafiles when we want to decompress the content.
+ */
public Compressor getCompressor() {
- return getCompressor(CarbonCommonConstants.DEFAULT_COMPRESSOR);
+ String compressorType = CarbonProperties.getInstance()
+ .getProperty(CarbonCommonConstants.COMPRESSOR,
CarbonCommonConstants.DEFAULT_COMPRESSOR);
+ if (!compressors.keySet().contains(compressorType)) {
--- End diff --
use compressors.containsKey directly
---
