com.pushinginertia.wicket.core.model.ConcatResourceModel.java Source code

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Here is the source code for com.pushinginertia.wicket.core.model.ConcatResourceModel.java

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/* Copyright (c) 2011-2015 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.model;

import com.pushinginertia.commons.core.validation.ValidateAs;
import com.pushinginertia.commons.ui.i18n.IResourceLookupKey;
import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.ResourceModel;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/**
 * A resource model that concatenates the output of its contained models.
 */
public class ConcatResourceModel extends AbstractReadOnlyModel<String> {
    private static final long serialVersionUID = 1L;

    public static class Builder {
        private final String separator;
        private final ArrayList<IModel<String>> modelList = new ArrayList<>();

        public Builder(final String separator) {
            ValidateAs.notNull(separator, "separator");
            this.separator = separator;
        }

        public Builder add(final IModel<String> model) {
            modelList.add(model);
            return this;
        }

        /**
         * Null-safe convenience method to append a {@link org.apache.wicket.model.ResourceModel} to the model list if
         * the given resolver is not null. When it's null, nothing changes.
         * @param resolver Something that provides a resource lookup key for the purpose of constructing a model.
         * @return This instance for method chaining.
         */
        public Builder add(final IResourceLookupKey resolver) {
            if (resolver != null) {
                return add(new ResourceModel(resolver.getResourceLookupKey()));
            }
            return this;
        }

        public ConcatResourceModel build() {
            return new ConcatResourceModel(separator, modelList);
        }
    }

    private final String separator;
    private final ArrayList<IModel<String>> modelList;

    private ConcatResourceModel(final String separator, final ArrayList<IModel<String>> modelList) {
        this.separator = separator;
        this.modelList = modelList;
    }

    /**
     * Instantiates a new model from a serializable list.
     * @param separator Separator string to insert between each concatenated model.
     * @param modelList List of models to concatenate.
     * @param <T> A serializable list.
     * @return New instance.
     */
    public static <T extends Serializable & List<IModel<String>>> ConcatResourceModel forList(
            final String separator, final T modelList) {
        return new ConcatResourceModel(separator, new ArrayList<>(modelList));
    }

    @Override
    public String getObject() {
        final StringBuilder sb = new StringBuilder();
        for (final IModel<String> model : modelList) {
            if (sb.length() > 0 && separator != null) {
                sb.append(separator);
            }
            sb.append(model.getObject());
        }
        return sb.toString();
    }

    @Override
    public void detach() {
        super.detach();
        for (final IModel<String> model : modelList) {
            model.detach();
        }
    }
}