com.pushinginertia.wicket.core.util.PageParametersUtils.java Source code

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Here is the source code for com.pushinginertia.wicket.core.util.PageParametersUtils.java

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/* Copyright (c) 2011-2013 Pushing Inertia
 * All rights reserved.  http://pushinginertia.com
 *
 * 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.pushinginertia.wicket.core.util;

import com.pushinginertia.commons.core.validation.ValidateAs;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.util.string.StringValue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;
import java.util.Set;

/**
 * Some common logic when working with page parameters.
 */
public final class PageParametersUtils {
    public static final Logger LOG = LoggerFactory.getLogger(PageParametersUtils.class);

    /**
     * Copies a {@link PageParameters} instance, pruning the key-value pairs for keys not given as parameters. In other
     * words, the copy will contain only key-value pairs where the key is specified as input to this method and the
     * key exists in the instance to copy.
     * @param pp instance to copy
     * @param keys list of keys to copy
     * @return a new instance containing a subset of the key-value pairs in the instance to copy
     */
    public static PageParameters copySubset(final PageParameters pp, final String... keys) {
        ValidateAs.notNull(pp, "pp");

        final PageParameters ppCopy = new PageParameters();
        final Set<String> ppKeys = pp.getNamedKeys();
        for (final String key : keys) {
            if (ppKeys.contains(key)) {
                final List<StringValue> valueList = pp.getValues(key);
                for (final StringValue value : valueList) {
                    ppCopy.add(key, value.toString());
                }
            }
        }
        return ppCopy;
    }

    /**
     * Retrieves an integer value from given page parameters, returning a default value if the name doesn't exist in the
     * parameters or the value cannot be parsed into an integer.
     * @param pp parameters to load the value from
     * @param name name to look up
     * @param defaultValue default value if one cannot be parsed
     * @return parsed value
     */
    public static int getInt(final PageParameters pp, final String name, final int defaultValue) {
        ValidateAs.notEmpty(name, "name");

        final StringValue value = pp.get(name);
        if (value.isEmpty()) {
            return defaultValue;
        }
        try {
            return Integer.parseInt(value.toString());
        } catch (final NumberFormatException e) {
            LOG.info("Page parameter value [{}] from name [{}] could not be parsed into an integer.", value, name);
            return defaultValue;
        }
    }

    /**
     * Retrieves a string value from given page parameters and identifies the matching enum value for that string. All
     * enumerations must be uppercased and the input is uppercased for the comparison operation. A default value is
     * returned if no value is given or it doesn't match any of the enumerations.
     * @param pp parameters to load the value from
     * @param name name to look up
     * @param enumClass enum type
     * @param defaultValue default value if one cannot be parsed
     * @param <E> enum type
     * @return parsed value
     */
    public static <E extends Enum> E getEnum(final PageParameters pp, final String name, final Class<E> enumClass,
            final E defaultValue) {
        ValidateAs.notEmpty(name, "name");

        final StringValue value = pp.get(name);
        if (value.isEmpty()) {
            return defaultValue;
        }

        final String upperValue = value.toString().toUpperCase();

        for (final E enumValue : enumClass.getEnumConstants()) {
            if (enumValue.name().equals(upperValue)) {
                return enumValue;
            }
        }

        return defaultValue;
    }

    private PageParametersUtils() {
    }
}