Java tutorial
/* * Licensed to CRATE Technology GmbH ("Crate") under one or more contributor * license agreements. See the NOTICE file distributed with this work for * additional information regarding copyright ownership. Crate 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. * * However, if you have executed another commercial license agreement * with Crate these terms will supersede the license and you may use the * software solely pursuant to the terms of the relevant commercial agreement. */ package io.crate.operation.scalar.cast; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Function; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; import com.google.common.collect.Maps; import io.crate.analyze.symbol.Symbol; import io.crate.metadata.FunctionIdent; import io.crate.metadata.FunctionInfo; import io.crate.types.ArrayType; import io.crate.types.DataType; import io.crate.types.DataTypes; import io.crate.types.SetType; import java.util.Arrays; import java.util.Locale; import java.util.Map; public class CastFunctionResolver { public static final String TRY_CAST_PREFIX = "try_"; public static class FunctionNames { public static final String TO_STRING = "to_string"; public static final String TO_INTEGER = "to_int"; public static final String TO_LONG = "to_long"; public static final String TO_TIMESTAMP = "to_timestamp"; public static final String TO_DOUBLE = "to_double"; public static final String TO_BOOLEAN = "to_boolean"; public static final String TO_FLOAT = "to_float"; public static final String TO_BYTE = "to_byte"; public static final String TO_SHORT = "to_short"; public static final String TO_IP = "to_ip"; public static final String TO_STRING_ARRAY = "to_string_array"; public static final String TO_LONG_ARRAY = "to_long_array"; public static final String TO_INTEGER_ARRAY = "to_int_array"; public static final String TO_DOUBLE_ARRAY = "to_double_array"; public static final String TO_BOOLEAN_ARRAY = "to_boolean_array"; public static final String TO_BYTE_ARRAY = "to_byte_array"; public static final String TO_FLOAT_ARRAY = "to_float_array"; public static final String TO_SHORT_ARRAY = "to_short_array"; public static final String TO_IP_ARRAY = "to_ip_array"; public static final String TO_GEO_POINT = "to_geo_point"; public static final String TO_GEO_SHAPE = "to_geo_shape"; static final String TO_STRING_SET = "to_string_set"; static final String TO_LONG_SET = "to_long_set"; static final String TO_INTEGER_SET = "to_integer_set"; static final String TO_DOUBLE_SET = "to_double_set"; static final String TO_BOOLEAN_SET = "to_boolean_set"; static final String TO_BYTE_SET = "to_byte_set"; static final String TO_FLOAT_SET = "to_float_set"; static final String TO_SHORT_SET = "to_short_set"; static final String TO_IP_SET = "to_ip_set"; } private static final ImmutableMap<DataType, String> PRIMITIVE_FUNCTION_MAP = new ImmutableMap.Builder<DataType, String>() .put(DataTypes.STRING, FunctionNames.TO_STRING).put(DataTypes.INTEGER, FunctionNames.TO_INTEGER) .put(DataTypes.LONG, FunctionNames.TO_LONG).put(DataTypes.TIMESTAMP, FunctionNames.TO_TIMESTAMP) .put(DataTypes.DOUBLE, FunctionNames.TO_DOUBLE).put(DataTypes.BOOLEAN, FunctionNames.TO_BOOLEAN) .put(DataTypes.FLOAT, FunctionNames.TO_FLOAT).put(DataTypes.BYTE, FunctionNames.TO_BYTE) .put(DataTypes.SHORT, FunctionNames.TO_SHORT).put(DataTypes.IP, FunctionNames.TO_IP).build(); private static final ImmutableMap<DataType, String> GEO_FUNCTION_MAP = new ImmutableMap.Builder<DataType, String>() .put(DataTypes.GEO_POINT, FunctionNames.TO_GEO_POINT) .put(DataTypes.GEO_SHAPE, FunctionNames.TO_GEO_SHAPE).build(); private static final ImmutableMap<DataType, String> ARRAY_FUNCTION_MAP = new ImmutableMap.Builder<DataType, String>() .put(new ArrayType(DataTypes.STRING), FunctionNames.TO_STRING_ARRAY) .put(new ArrayType(DataTypes.LONG), FunctionNames.TO_LONG_ARRAY) .put(new ArrayType(DataTypes.INTEGER), FunctionNames.TO_INTEGER_ARRAY) .put(new ArrayType(DataTypes.DOUBLE), FunctionNames.TO_DOUBLE_ARRAY) .put(new ArrayType(DataTypes.BOOLEAN), FunctionNames.TO_BOOLEAN_ARRAY) .put(new ArrayType(DataTypes.BYTE), FunctionNames.TO_BYTE_ARRAY) .put(new ArrayType(DataTypes.FLOAT), FunctionNames.TO_FLOAT_ARRAY) .put(new ArrayType(DataTypes.SHORT), FunctionNames.TO_SHORT_ARRAY) .put(new ArrayType(DataTypes.IP), FunctionNames.TO_IP_ARRAY).build(); private static final ImmutableMap<DataType, String> SET_FUNCTION_MAP = new ImmutableMap.Builder<DataType, String>() .put(new SetType(DataTypes.STRING), FunctionNames.TO_STRING_SET) .put(new SetType(DataTypes.LONG), FunctionNames.TO_LONG_SET) .put(new SetType(DataTypes.INTEGER), FunctionNames.TO_INTEGER_SET) .put(new SetType(DataTypes.DOUBLE), FunctionNames.TO_DOUBLE_SET) .put(new SetType(DataTypes.BOOLEAN), FunctionNames.TO_BOOLEAN_SET) .put(new SetType(DataTypes.BYTE), FunctionNames.TO_BYTE_SET) .put(new SetType(DataTypes.FLOAT), FunctionNames.TO_FLOAT_SET) .put(new SetType(DataTypes.SHORT), FunctionNames.TO_SHORT_SET) .put(new SetType(DataTypes.IP), FunctionNames.TO_IP_SET).build(); static final ImmutableMap<DataType, String> FUNCTION_MAP = new ImmutableMap.Builder<DataType, String>() .putAll(PRIMITIVE_FUNCTION_MAP).putAll(GEO_FUNCTION_MAP).putAll(ARRAY_FUNCTION_MAP) .putAll(SET_FUNCTION_MAP).build(); public static Symbol generateCastFunction(Symbol sourceSymbol, DataType targetType, boolean tryCast) { DataType sourceType = sourceSymbol.valueType(); FunctionInfo functionInfo = functionInfo(sourceType, targetType, tryCast); //noinspection ArraysAsListWithZeroOrOneArgument # arguments of Function must be mutable return new io.crate.analyze.symbol.Function(functionInfo, Arrays.asList(sourceSymbol)); } /** * resolve the needed conversion function info based on the wanted return data type */ @VisibleForTesting static FunctionInfo functionInfo(DataType dataType, DataType returnType, boolean tryCast) { String functionName = FUNCTION_MAP.get(returnType); if (functionName == null) { throw new IllegalArgumentException(String.format(Locale.ENGLISH, "No cast function found for return type %s", returnType.getName())); } functionName = tryCast ? TRY_CAST_PREFIX + functionName : functionName; return new FunctionInfo(new FunctionIdent(functionName, ImmutableList.of(dataType)), returnType); } public static boolean supportsExplicitConversion(DataType returnType) { return FUNCTION_MAP.get(returnType) != null; } private static Function<String, String> TO_TRY_CAST_MAP = new Function<String, String>() { @Override public String apply(String functionName) { return TRY_CAST_PREFIX + functionName; } }; public static Map<DataType, String> tryFunctionsMap() { return Maps.transformValues(FUNCTION_MAP, TO_TRY_CAST_MAP); } }