org.callimachusproject.rewrite.RedirectAdviceFactory.java Source code

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Here is the source code for org.callimachusproject.rewrite.RedirectAdviceFactory.java

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/*
 * Copyright (c) 2013 3 Round Stones Inc., Some Rights Reserved
 *
 * 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 org.callimachusproject.rewrite;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

import org.apache.http.HttpVersion;
import org.apache.http.StatusLine;
import org.apache.http.message.BasicStatusLine;
import org.callimachusproject.annotations.alternate;
import org.callimachusproject.annotations.canonical;
import org.callimachusproject.annotations.describedby;
import org.callimachusproject.annotations.moved;
import org.callimachusproject.annotations.resides;
import org.callimachusproject.annotations.type;
import org.callimachusproject.fluid.FluidType;
import org.openrdf.annotations.Iri;
import org.openrdf.repository.object.advice.Advice;
import org.openrdf.repository.object.advice.AdviceFactory;
import org.openrdf.repository.object.advice.AdviceProvider;

public class RedirectAdviceFactory implements AdviceProvider, AdviceFactory {

    @Override
    public AdviceFactory getAdviserFactory(Class<?> annotationType) {
        if (canonical.class.equals(annotationType))
            return this;
        if (alternate.class.equals(annotationType))
            return this;
        if (describedby.class.equals(annotationType))
            return this;
        if (resides.class.equals(annotationType))
            return this;
        if (moved.class.equals(annotationType))
            return this;
        return null;
    }

    @Override
    public Advice createAdvice(Method method) {
        Substitution[] replacers = createSubstitution(getCommands(method));
        String[] bindingNames = getBindingNames(method, replacers);
        FluidType[] bindingTypes = getBindingTypes(method, bindingNames);
        StatusLine status = getStatusLine(method);
        return new RedirectAdvice(bindingNames, bindingTypes, replacers, status, method);
    }

    String[] getBindingNames(Method method, Substitution[] substitutions) {
        Annotation[][] anns = method.getParameterAnnotations();
        String[] bindingNames = new String[anns.length];
        for (int i = 0; i < bindingNames.length; i++) {
            for (Annotation ann : anns[i]) {
                if (Iri.class.equals(ann.annotationType())) {
                    String local = local(((Iri) ann).value());
                    for (Substitution substitution : substitutions) {
                        if (substitution.containsVariableName(local)) {
                            bindingNames[i] = local;
                        }
                    }
                }
            }
        }
        return bindingNames;
    }

    FluidType[] getBindingTypes(Method method, String[] bindingNames) {
        Type[] types = method.getGenericParameterTypes();
        Annotation[][] anns = method.getParameterAnnotations();
        FluidType[] bindingTypes = new FluidType[anns.length];
        loop: for (int i = 0; i < bindingTypes.length; i++) {
            if (bindingNames[i] == null)
                continue;
            for (Annotation ann : anns[i]) {
                if (type.class.equals(ann.annotationType())) {
                    bindingTypes[i] = new FluidType(types[i], ((type) ann).value());
                    continue loop;
                }
            }
            bindingTypes[i] = new FluidType(types[i]);
        }
        return bindingTypes;
    }

    Substitution[] createSubstitution(String[] commands) {
        if (commands == null)
            return null;
        Substitution[] result = new Substitution[commands.length];
        for (int i = 0; i < result.length; i++) {
            result[i] = Substitution.compile(commands[i]);
        }
        return result;
    }

    String local(String iri) {
        String string = iri;
        if (string.lastIndexOf('#') >= 0) {
            string = string.substring(string.lastIndexOf('#') + 1);
        }
        if (string.lastIndexOf('?') >= 0) {
            string = string.substring(string.lastIndexOf('?') + 1);
        }
        if (string.lastIndexOf('/') >= 0) {
            string = string.substring(string.lastIndexOf('/') + 1);
        }
        if (string.lastIndexOf(':') >= 0) {
            string = string.substring(string.lastIndexOf(':') + 1);
        }
        return string;
    }

    private String[] getCommands(Method method) {
        if (method.isAnnotationPresent(canonical.class))
            return method.getAnnotation(canonical.class).value();
        if (method.isAnnotationPresent(alternate.class))
            return method.getAnnotation(alternate.class).value();
        if (method.isAnnotationPresent(describedby.class))
            return method.getAnnotation(describedby.class).value();
        if (method.isAnnotationPresent(resides.class))
            return method.getAnnotation(resides.class).value();
        if (method.isAnnotationPresent(moved.class))
            return method.getAnnotation(moved.class).value();
        return null;
    }

    private StatusLine getStatusLine(Method method) {
        if (method.isAnnotationPresent(alternate.class))
            return new BasicStatusLine(HttpVersion.HTTP_1_1, 302, "Alternate");
        if (method.isAnnotationPresent(describedby.class))
            return new BasicStatusLine(HttpVersion.HTTP_1_1, 303, "Described By");
        if (method.isAnnotationPresent(resides.class))
            return new BasicStatusLine(HttpVersion.HTTP_1_1, 307, "Resides");
        if (method.isAnnotationPresent(moved.class))
            return new BasicStatusLine(HttpVersion.HTTP_1_1, 308, "Moved");
        throw new AssertionError();
    }

}