ParsedQuickSilver.java

/*******************************************************************************
 *
 * Copyright (c) 2004-2009 Oracle Corporation.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * 
 *    Kohsuke Kawaguchi
 *
 *
 *******************************************************************************/ 

package hudson.search;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.HashMap;
import java.beans.Introspector;

/**
 * Parsed {@link QuickSilver}s so that {@link SearchIndex} can be easily
 * created. One instance per one class.
 *
 * @author Kohsuke Kawaguchi
 */
final class ParsedQuickSilver {

    private static final Map<Class, ParsedQuickSilver> TABLE = new HashMap<Class, ParsedQuickSilver>();

    synchronized static ParsedQuickSilver get(Class<? extends SearchableModelObject> clazz) {
        ParsedQuickSilver pqs = TABLE.get(clazz);
        if (pqs == null) {
            TABLE.put(clazz, pqs = new ParsedQuickSilver(clazz));
        }
        return pqs;
    }
    private final List<Getter> getters = new ArrayList<Getter>();

    private ParsedQuickSilver(Class<? extends SearchableModelObject> clazz) {
        QuickSilver qs;

        for (Method m : clazz.getMethods()) {
            qs = m.getAnnotation(QuickSilver.class);
            if (qs != null) {
                String url = stripGetPrefix(m);
                if (qs.value().length == 0) {
                    getters.add(new MethodGetter(url, splitName(url), m));
                } else {
                    for (String name : qs.value()) {
                        getters.add(new MethodGetter(url, name, m));
                    }
                }
            }
        }
        for (Field f : clazz.getFields()) {
            qs = f.getAnnotation(QuickSilver.class);
            if (qs != null) {
                if (qs.value().length == 0) {
                    getters.add(new FieldGetter(f.getName(), splitName(f.getName()), f));
                } else {
                    for (String name : qs.value()) {
                        getters.add(new FieldGetter(f.getName(), name, f));
                    }
                }
            }
        }
    }

    /**
     * Convert names like "abcDefGhi" to "abc def ghi".
     */
    private String splitName(String url) {
        StringBuilder buf = new StringBuilder(url.length() + 5);
        for (String token : url.split("(?<=[a-z])(?=[A-Z])")) {
            if (buf.length() > 0) {
                buf.append(' ');
            }
            buf.append(Introspector.decapitalize(token));
        }
        return buf.toString();
    }

    private String stripGetPrefix(Method m) {
        String n = m.getName();
        if (n.startsWith("get")) {
            n = Introspector.decapitalize(n.substring(3));
        }
        return n;
    }

    static abstract class Getter {

        final String url;
        final String searchName;

        protected Getter(String url, String searchName) {
            this.url = url;
            this.searchName = searchName;
        }

        abstract Object get(Object obj);
    }

    static final class MethodGetter extends Getter {

        private final Method method;

        public MethodGetter(String url, String searchName, Method method) {
            super(url, searchName);
            this.method = method;
        }

        Object get(Object obj) {
            try {
                return method.invoke(obj);
            } catch (IllegalAccessException e) {
                throw toError(e);
            } catch (InvocationTargetException e) {
                Throwable x = e.getTargetException();
                if (x instanceof Error) {
                    throw (Error) x;
                }
                if (x instanceof RuntimeException) {
                    throw (RuntimeException) x;
                }
                throw new Error(e);
            }
        }
    }

    static final class FieldGetter extends Getter {

        private final Field field;

        public FieldGetter(String url, String searchName, Field field) {
            super(url, searchName);
            this.field = field;
        }

        Object get(Object obj) {
            try {
                return field.get(obj);
            } catch (IllegalAccessException e) {
                throw toError(e);
            }
        }
    }

    private static IllegalAccessError toError(IllegalAccessException e) {
        IllegalAccessError iae = new IllegalAccessError();
        iae.initCause(e);
        return iae;
    }

    public void addTo(SearchIndexBuilder builder, final Object instance) {
        for (final Getter getter : getters) {
            builder.add(new SearchItem() {
                public String getSearchName() {
                    return getter.searchName;
                }

                public String getSearchUrl() {
                    return getter.url;
                }

                public SearchIndex getSearchIndex() {
                    Object child = getter.get(instance);
                    if (child == null) {
                        return SearchIndex.EMPTY;
                    }
                    return ((SearchableModelObject) child).getSearchIndex();
                }
            });
        }
    }
}