com.formkiq.core.form.bean.StringConverter.java Source code

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Here is the source code for com.formkiq.core.form.bean.StringConverter.java

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/*
 * Copyright (C) 2018 FormKiQ Inc.
 *
 * 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.
 */
package com.formkiq.core.form.bean;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.beanutils.converters.AbstractConverter;

/**
 * {@link org.apache.commons.beanutils.Converter} implementation that converts
 * an incoming object into a <code>java.lang.String</code> object.
 *
 * Differs from {@link org.apache.commons.beanutils.converters.StringConverter}
 * in that handles converting {@link java.lang.String} to {@link java.util.List}
 */
public class StringConverter extends AbstractConverter {

    /**
     * default contructor.
     */
    public StringConverter() {
        super();
    }

    /**
     * Construct a <b>java.lang.String</b> <i>Converter</i> that returns
     * a default value if an error occurs.
     *
     * @param defaultValue The default value to be returned
     * if the value to be converted is missing or an error
     * occurs converting the value.
     */
    public StringConverter(final Object defaultValue) {
        super(defaultValue);
    }

    /**
     * Return the default type this <code>Converter</code> handles.
     *
     * @return The default type this <code>Converter</code> handles.
     * @since 1.8.0
     */
    @Override
    protected Class<?> getDefaultType() {
        return String.class;
    }

    /**
     * Convert the specified input object into an output object of the
     * specified type.
     *
     * @param <T> Target type of the conversion.
     * @param type Data type to which this value should be converted.
     * @param value The input value to be converted.
     * @return The converted value.
     * @throws Throwable if an error occurs converting to the specified type
     * @since 1.8.0
     */
    @SuppressWarnings("unchecked")
    @Override
    protected <T> T convertToType(final Class<T> type, final Object value) throws Throwable {
        // We have to support Object, too, because this class is sometimes
        // used for a standard to Object conversion
        if (String.class.equals(type) || Object.class.equals(type)) {
            return type.cast(value.toString());
        }

        if (type.isAssignableFrom(List.class)) {
            return (T) new ArrayList<>(Arrays.asList(value.toString().split("\n")));
        }

        throw conversionException(type, value);
    }

    @Override
    protected Object convertArray(final Object value) {

        if (value instanceof Collection) {
            Collection<?> collection = (Collection<?>) value;

            StringBuilder buffer = new StringBuilder();

            for (Iterator<?> iter = collection.iterator(); iter.hasNext();) {
                buffer.append(iter.next());

                if (iter.hasNext()) {
                    buffer.append("\n");
                }
            }

            return buffer.toString();
        }

        return super.convertArray(value);
    }
}