SimpleDB/StringField.java at master · SeanLachhander/SimpleDB · GitHub

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packagesimpledb;

importjava.io.*;

/**
 * Instance of Field that stores a single String of a fixed length.
 */
publicclassStringFieldimplementsField {
privateStringvalue;
privateintmaxSize;

publicStringgetValue() {
returnvalue;
 }

/**
 * Constructor.
 *
 * @param s The value of this field.
 * @param maxSize The maximum size of this string

 */
publicStringField(Strings, intmaxSize) {
this.maxSize = maxSize;

if (s.length() > maxSize)
value = s.substring(0,maxSize);
else
value = s;
 }

publicStringtoString() {
returnvalue;
 }

publicinthashCode() {
returnvalue.hashCode();
 }

publicbooleanequals(Objectfield) {
return ((StringField) field).value.equals(value);
 }

/** Write this string to dos. Always writes maxSize + 4 bytes to the
 passed in dos. First four bytes are string length, next bytes are
 string, with remainder padded with 0 to maxSize.
 @param dos Where the string is written
 */
publicvoidserialize(DataOutputStreamdos) throwsIOException {
Strings = value;
intoverflow = maxSize - s.length();
if (overflow < 0) {
Stringnews = s.substring(0,maxSize);
s = news;
 }
dos.writeInt(s.length());
dos.writeBytes(s);
while (overflow-- > 0)
dos.write((byte)0);
 }

/**
 * Compare the specified field to the value of this Field.
 * Return semantics are as specified by Field.compare
 *
 * @throws IllegalCastException if val is not a StringField
 * @see Field#compare
 */
publicbooleancompare(Predicate.Opop, Fieldval) {

StringFieldiVal = (StringField) val;
intcmpVal = value.compareTo(iVal.value);

switch (op) {
caseEQUALS:
returncmpVal == 0;

caseNOT_EQUALS:
returncmpVal != 0;

caseGREATER_THAN:
returncmpVal > 0;

caseGREATER_THAN_OR_EQ:
returncmpVal >= 0;

caseLESS_THAN:
returncmpVal < 0;

caseLESS_THAN_OR_EQ:
returncmpVal <= 0;

caseLIKE:
returnvalue.indexOf(iVal.value) >= 0;
 }

returnfalse;
 }
/**
 * @return the Type for this Field
 */
publicTypegetType() {

returnType.STRING_TYPE;
	}
}