com.isotrol.impe3.api.PathSegmentsTransformers.java Source code

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Here is the source code for com.isotrol.impe3.api.PathSegmentsTransformers.java

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/**
 * This file is part of Port@l
 * Port@l 3.0 - Portal Engine and Management System
 * Copyright (C) 2010  Isotrol, SA.  http://www.isotrol.com
 *
 * Port@l is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Port@l is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Port@l.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.isotrol.impe3.api;

import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

/**
 * Transformer functions for PathSegments.
 * @author Andres Rodriguez.
 */
public final class PathSegmentsTransformers {
    /** Not instantiable. */
    private PathSegmentsTransformers() {
        throw new AssertionError();
    }

    /**
     * Returns a new transformer that inserts segments at the beginning of the provided path.
     * @param segments Segments to add.
     * @return The requested transformer.
     */
    public static Function<PathSegments, PathSegments> insert(final PathSegments segments) {
        if (segments == null || segments.isEmpty()) {
            return Functions.identity();
        }
        return new Function<PathSegments, PathSegments>() {
            public PathSegments apply(PathSegments input) {
                if (input == null || input.isEmpty()) {
                    return segments;
                }
                return segments.add(input);
            }

            public String toString() {
                return String.format("Insert transformer: %s", segments);
            };
        };
    }

    /**
     * Returns a new transformer that appends segments to the provided path.
     * @param segments Segments to append.
     * @return The requested transformer.
     */
    public static Function<PathSegments, PathSegments> append(final PathSegments segments) {
        if (segments == null || segments.isEmpty()) {
            return Functions.identity();
        }
        return new Function<PathSegments, PathSegments>() {
            public PathSegments apply(PathSegments input) {
                if (input == null || input.isEmpty()) {
                    return segments;
                }
                return input.add(segments);
            }

            public String toString() {
                return String.format("Append transformer: %s", segments);
            };
        };
    }

    /**
     * Returns a new transformer that appends an extension to the last segment of the provided path.
     * @param extension Extension to append.
     * @return The requested transformer.
     */
    public static Function<PathSegments, PathSegments> extension(final String extension) {
        if (extension == null || extension.length() == 0) {
            return Functions.identity();
        }
        return new Function<PathSegments, PathSegments>() {
            public PathSegments apply(PathSegments input) {
                if (input == null || input.isEmpty()) {
                    return input;
                }
                String last = input.last();
                if (last == null || last.length() == 0) {
                    return input;
                }
                last = new StringBuilder(last).append('.').append(extension).toString();
                return PathSegments.of(false, Iterables.concat(input.consumeLast(), ImmutableList.of(last)));
            }

            public String toString() {
                return String.format("Extension transformer: %s", extension);
            };
        };
    }
}