Transforms the given value to an instance of the given type. - Java Reflection

Java examples for Reflection:Object

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Description

Transforms the given value to an instance of the given type.

Demo Code

/*//from   ww  w.j  a v a2 s  . c  om
 * #%L
 * Wisdom-Framework
 * %%
 * Copyright (C) 2013 - 2014 Wisdom Framework
 * %%
 * Licensed 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.
 * #L%
 */
//package com.java2s;

import java.sql.SQLException;

public class Main {


    /**
     * Transforms the given value to an instance of the given type.
     * @param value the value
     * @param type the type
     * @return an instance of the type having the wrapped value
     * @throws SQLException if the conversion is not possible.
     */
    public static Object toBasicType(String value, String type)
            throws SQLException {

        // Early return from first "if" condition that evaluates to true

        if (value == null) {
            return null;
        }

        if (type == null || type.equals(String.class.getName())) {
            return value;
        }

        if (type.equals(Integer.class.getName())
                || type.equals(int.class.getName())) {
            try {
                return Integer.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Integer", value);
            }
        }

        if (type.equals(Float.class.getName())
                || type.equals(float.class.getName())) {
            try {
                return Float.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Float", value);
            }
        }

        if (type.equals(Long.class.getName())
                || type.equals(long.class.getName())) {
            try {
                return Long.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Long", value);
            }
        }

        if (type.equals(Double.class.getName())
                || type.equals(double.class.getName())) {
            try {
                return Double.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Double", value);
            }
        }

        if (type.equals(Character.class.getName())
                || type.equals(char.class.getName())) {
            if (value.length() != 1) {
                throw new SQLException("Invalid Character value: " + value);
            }
            return value.charAt(0);
        }

        if (type.equals(Byte.class.getName())
                || type.equals(byte.class.getName())) {
            try {
                return Byte.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Byte", value);
            }
        }

        if (type.equals(Short.class.getName())
                || type.equals(short.class.getName())) {
            try {
                return Short.valueOf(value);
            } catch (NumberFormatException e) {
                throwSQLException(e, "Short", value);
            }
        }

        // Will be "false" if not in correct format...
        if (type.equals(Boolean.class.getName())
                || type.equals(boolean.class.getName())) {
            return Boolean.valueOf(value);
        }

        throw new SQLException("Unrecognized property type: " + type);
    }

    /**
     * An helper method to build and throw a SQL Exception when a property cannot be set.
     * @param cause the cause
     * @param theType the type of the property
     * @param value the value of the property
     * @throws SQLException the SQL Exception
     */
    public static void throwSQLException(Exception cause, String theType,
            String value) throws SQLException {
        throw new SQLException("Invalid " + theType + " value: " + value,
                cause);
    }
}

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