leveld-api:(6)Options

leveldb/Options.java at master · dain/leveldb · GitHub

判断Argment是否为null：

static void checkArgNotNull(Object value, String name)
    {
        if (value == null) {
            throw new IllegalArgumentException("The " + name + " argument cannot be null");
        }
    }

createIfMissing：数据库打开时，若数据库丢失则重新创建一份

public boolean createIfMissing()
    {
        return createIfMissing;
    }

    public Options createIfMissing(boolean createIfMissing)
    {
        this.createIfMissing = createIfMissing;
        return this;
    }

errorIfexists:数据库打开时如果是true则报错

public boolean errorIfExists()
    {
        return errorIfExists;
    }

    public Options errorIfExists(boolean errorIfExists)
    {
        this.errorIfExists = errorIfExists;
        return this;
    }

writeBufferSize:memetable的大小超过writebuffersize时，转为immemtable

public int writeBufferSize()
    {
        return writeBufferSize;
    }

    public Options writeBufferSize(int writeBufferSize)
    {
        this.writeBufferSize = writeBufferSize;
        return this;
    }

maxOpenFile:DB可打开的最大文件数

public int maxOpenFiles()
    {
        return maxOpenFiles;
    }

    public Options maxOpenFiles(int maxOpenFiles)
    {
        this.maxOpenFiles = maxOpenFiles;
        return this;
    }

blockRestartInterval: block重启点之间的key的个数

public int blockRestartInterval()
    {
        return blockRestartInterval;
    }

    public Options blockRestartInterval(int blockRestartInterval)
    {
        this.blockRestartInterval = blockRestartInterval;
        return this;
    }

blockSize:每一个block大小，指压缩数据大小

    public int blockSize()
    {
        return blockSize;
    }

    public Options blockSize(int blockSize)
    {
        this.blockSize = blockSize;
        return this;
    }

CompressionType:压缩block的方式

public CompressionType compressionType()
    {
        return compressionType;
    }

    public Options compressionType(CompressionType compressionType)
    {
        checkArgNotNull(compressionType, "compressionType");
        this.compressionType = compressionType;
        return this;
    }

verifChecksums:所有读取数据都会校验

public boolean verifyChecksums()
    {
        return verifyChecksums;
    }

    public Options verifyChecksums(boolean verifyChecksums)
    {
        this.verifyChecksums = verifyChecksums;
        return this;
    }

cacheSize:缓存大小

public long cacheSize()
    {
        return cacheSize;
    }

    public Options cacheSize(long cacheSize)
    {
        this.cacheSize = cacheSize;
        return this;
    }

DBcomparator:

public DBComparator comparator()
    {
        return comparator;
    }

    public Options comparator(DBComparator comparator)
    {
        this.comparator = comparator;
        return this;
    }

logger:db产生的处理和错误日志写入指定文件，若为空，则在同一个目录中创建一个文件写入db

public Logger logger()
    {
        return logger;
    }

    public Options logger(Logger logger)
    {
        this.logger = logger;
        return this;
    }

paranoidchecks:如果为true，数据处理过程会严格检查数据，检查到任何数据都会提前停止

 public boolean paranoidChecks()
    {
        return paranoidChecks;
    }

    public Options paranoidChecks(boolean paranoidChecks)
    {
        this.paranoidChecks = paranoidChecks;
        return this;
    }