com.datastax.oss.driver.internal.core.type.codec.extras.array.AbstractListToArrayCodec Maven / Gradle / Ivy
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* 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 com.datastax.oss.driver.internal.core.type.codec.extras.array;
import com.datastax.oss.driver.api.core.type.DataType;
import com.datastax.oss.driver.api.core.type.ListType;
import com.datastax.oss.driver.api.core.type.codec.TypeCodec;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import com.datastax.oss.driver.internal.core.type.codec.ParseUtils;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.lang.reflect.Array;
import java.util.Objects;
/**
* Base class for all codecs dealing with Java arrays. This class aims to reduce the amount of code
* required to create such codecs.
*
* @param The Java array type this codec handles
*/
public abstract class AbstractListToArrayCodec implements TypeCodec {
@NonNull protected final ListType cqlType;
@NonNull protected final GenericType javaType;
/**
* @param cqlType The CQL type. Must be a list type.
* @param arrayType The Java type. Must be an array class.
*/
protected AbstractListToArrayCodec(
@NonNull ListType cqlType, @NonNull GenericType arrayType) {
this.cqlType = Objects.requireNonNull(cqlType, "cqlType cannot be null");
this.javaType = Objects.requireNonNull(arrayType, "arrayType cannot be null");
if (!arrayType.isArray()) {
throw new IllegalArgumentException("Expecting Java array class, got " + arrayType);
}
}
@NonNull
@Override
public GenericType getJavaType() {
return javaType;
}
@NonNull
@Override
public DataType getCqlType() {
return cqlType;
}
@NonNull
@Override
public String format(@Nullable ArrayT array) {
if (array == null) {
return "NULL";
}
int length = Array.getLength(array);
StringBuilder sb = new StringBuilder();
sb.append('[');
for (int i = 0; i < length; i++) {
if (i != 0) {
sb.append(",");
}
formatElement(sb, array, i);
}
sb.append(']');
return sb.toString();
}
@Nullable
@Override
public ArrayT parse(@Nullable String value) {
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL")) {
return null;
}
int idx = skipSpaces(value, 0);
idx = skipOpeningBracket(value, idx);
idx = skipSpaces(value, idx);
if (value.charAt(idx) == ']') {
return newInstance(0);
}
// first pass: determine array length
int length = getArrayLength(value, idx);
// second pass: parse elements
ArrayT array = newInstance(length);
int i = 0;
for (; idx < value.length(); i++) {
int n = skipLiteral(value, idx);
parseElement(value.substring(idx, n), array, i);
idx = skipSpaces(value, n);
if (value.charAt(idx) == ']') {
return array;
}
idx = skipComma(value, idx);
idx = skipSpaces(value, idx);
}
throw new IllegalArgumentException(
String.format("Malformed list value \"%s\", missing closing ']'", value));
}
/**
* Creates a new array instance with the given size.
*
* @param size The size of the array to instantiate.
* @return a new array instance with the given size.
*/
@NonNull
protected abstract ArrayT newInstance(int size);
/**
* Formats the {@code index}th element of {@code array} to {@code output}.
*
* @param output The StringBuilder to write to.
* @param array The array to read from.
* @param index The element index.
*/
protected abstract void formatElement(
@NonNull StringBuilder output, @NonNull ArrayT array, int index);
/**
* Parses the {@code index}th element of {@code array} from {@code input}.
*
* @param input The String to read from.
* @param array The array to write to.
* @param index The element index.
*/
protected abstract void parseElement(@NonNull String input, @NonNull ArrayT array, int index);
private int getArrayLength(String value, int idx) {
int length = 1;
for (; idx < value.length(); length++) {
idx = skipLiteral(value, idx);
idx = skipSpaces(value, idx);
if (value.charAt(idx) == ']') {
break;
}
idx = skipComma(value, idx);
idx = skipSpaces(value, idx);
}
return length;
}
private int skipComma(String value, int idx) {
if (value.charAt(idx) != ',') {
throw new IllegalArgumentException(
String.format(
"Cannot parse list value from \"%s\", at character %d expecting ',' but got '%c'",
value, idx, value.charAt(idx)));
}
return idx + 1;
}
private int skipOpeningBracket(String value, int idx) {
if (value.charAt(idx) != '[') {
throw new IllegalArgumentException(
String.format(
"cannot parse list value from \"%s\", at character %d expecting '[' but got '%c'",
value, idx, value.charAt(idx)));
}
return idx + 1;
}
private int skipSpaces(String value, int idx) {
try {
return ParseUtils.skipSpaces(value, idx);
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException(
String.format(
"Cannot parse list value from \"%s\", at character %d expecting space but got '%c'",
value, idx, value.charAt(idx)),
e);
}
}
private int skipLiteral(String value, int idx) {
try {
return ParseUtils.skipCQLValue(value, idx);
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException(
String.format(
"Cannot parse list value from \"%s\", invalid CQL value at character %d", value, idx),
e);
}
}
}