source: java/main/src/main/java/com/framsticks/core/Path.java @ 96

package com.framsticks.core;

import com.framsticks.params.AccessInterface;
import com.framsticks.params.CompositeParam;
import com.framsticks.params.Param;
import com.framsticks.util.FramsticksException;
import com.framsticks.util.dispatching.Dispatching;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;

import org.apache.commons.collections.ListUtils;

/**
 * @author Piotr Sniegowski
 */
@Immutable
public final class Path {
        // private final static Logger log = Logger.getLogger(Path.class.getName());

        final Instance instance;
        final String textual;
        final LinkedList<Node> nodes;

        protected static Object getKnownChild(Instance instance, AccessInterface access, CompositeParam param) {
                Object child = access.get(param, Object.class);
                if (child == null) {
                        return null;
                }
                try {
                        instance.prepareAccess(param);
                        return child;
                } catch (FramsticksException e) {
                }
                return null;
        }

        /**
         * @param instance
         * @param textual
         * @param nodes
         */
        Path(Instance instance, String textual, LinkedList<Node> nodes) {
                this.instance = instance;
                this.textual = textual;
                this.nodes = nodes;
        }

        public Path appendNode(Node node) {
                assert isResolved();
                return new PathBuilder().instance(instance).textual(textual + ((size() == 1) ? "" : "/") + node.getParam().getId()).add(nodes).add(node).finish();
        }

        public Path appendParam(CompositeParam param) {
                assert isResolved();
                return appendNode(new Node(param, null));
        }

        public static class PathBuilder {

                Instance instance;
                String textual;
                final LinkedList<Node> nodes = new LinkedList<Node>();

                public Path finish() {
                        assert instance != null;
                        assert textual != null;
                        return new Path(instance, textual, nodes);
                }

                public PathBuilder()
                {
                }

                public PathBuilder instance(Instance instance) {
                        this.instance = instance;
                        return this;
                }

                public PathBuilder textual(String textual) {
                        this.textual = textual;
                        return this;
                }

                public PathBuilder add(List<Node> nodes) {
                        this.nodes.addAll(nodes);
                        return this;
                }

                public PathBuilder add(Node node) {
                        this.nodes.add(node);
                        return this;
                }

                public PathBuilder setLast(Object object) {
                        Node n = nodes.pollLast();
                        nodes.add(new Node(n.getParam(), object));
                        return this;
                }

                public PathBuilder buildUpTo(List<Node> nodes, Node node) {
                        StringBuilder b = new StringBuilder();
                        boolean add = false;
                        for (Node n : nodes) {
                                this.nodes.add(n);
                                if (add) {
                                        b.append("/").append(n.getParam().getId());
                                }
                                add = true;
                                if (n == node) {
                                        break;
                                }
                        }
                        this.textual = (nodes.size() == 1) ? "/" : b.toString();
                        return this;
                }

                public static Iterator<String> splitPath(String path) {
                        List<String> list = new LinkedList<String>();
                        for (String s : path.split("/")) {
                                if (!s.isEmpty()) {
                                        list.add(s);
                                }
                        }
                        return list.iterator();
                }

                public PathBuilder resolve(@Nonnull Instance instance, String textual) {

                        assert nodes.isEmpty();
                        assert instance.isActive();
                        this.instance = instance;

                        nodes.add(instance.getRoot());
                        Node current = instance.getRoot();

                        StringBuilder b = new StringBuilder();
                        Iterator<String> i = splitPath(textual);
                        while (i.hasNext() && current.getObject() != null) {
                                AccessInterface access = instance.prepareAccess(current.getParam());
                                if (access == null) {
                                        break;
                                }
                                String e = i.next();
                                Param p = access.getParam(e);
                                if (!(p instanceof CompositeParam)) {
                                        //entries.add(new Entry());
                                        break;
                                }
                                CompositeParam c = (CompositeParam)p;
                                b.append("/").append(e);
                                access.select(current.getObject());
                                current = new Node(c, getKnownChild(instance, access, c));
                                nodes.add(current);
                        }
                        this.textual = (nodes.size() == 1) ? "/" : b.toString();

                        return this;
                }
        }

        public static PathBuilder build() {
                return new PathBuilder();
        }

        public Path appendResolution(Object object) {
                assert !isResolved();
                Path result = new PathBuilder().textual(textual).instance(instance).add(nodes).setLast(object).finish();
                assert size() == result.size();
                return result;
        }

        public final Object getTopObject() {
                return getTop().getObject();
        }

        public final Node getTop() {
                return nodes.getLast();
        }

        public final Node getUnder() {
                assert nodes.size() >= 2;
                return nodes.get(nodes.size() - 2);
        }

        public final String getTextual() {
                return textual;
        }

        public String toString() {
                return instance + textual + (!isResolved() ? "!" : "");
        }

        public final int size() {
                assert Dispatching.isThreadSafe();
                return nodes.size();
        }

        public final boolean isResolved() {
                assert Dispatching.isThreadSafe();
                return getTop().getObject() != null;
        }

        public final boolean isResolved(String textual) {
                assert Dispatching.isThreadSafe();
                return isTheSame(textual) && isResolved();
        }

        public final boolean isTheSame(String textual) {
                assert Dispatching.isThreadSafe();
                return this.textual.equals(textual);
        }

        public final @Nonnull Instance getInstance() {
                assert Dispatching.isThreadSafe();
                return instance;
        }

        public Path tryResolveIfNeeded() {
                if (isResolved()) {
                        return this;
                }
                return tryFindResolution();
        }

        /** Attach resolution at end, if available.
         *
         * @return Modified path, if resolution was available, this otherwise.
         */
        public Path tryFindResolution() {
                assert instance.isActive();
                assert !isResolved();
                if (size() == 1) {
                        return Path.build().resolve(instance, "/").finish();//appendResolution(instance.root.object);
                }
                Object child = getKnownChild(instance, InstanceUtils.bindAccess(instance, getUnder()), getTop().getParam());
                if (child == null) {
                        return this;
                }
                return appendResolution(child);
        }

        public boolean matches(Path p) {
                assert Dispatching.isThreadSafe();
                assert instance == p.instance;
                Iterator<Node> a = nodes.iterator();
                Iterator<Node> b = p.nodes.iterator();
                while (a.hasNext() && b.hasNext()) {
                        Node an = a.next();
                        Node bn = b.next();
                        if (an.object != bn.object) {
                                return false;
                        }
                }
                return a.hasNext() == b.hasNext();
        }

        public String getLastElement() {
                return getTop().getParam().getId();
        }

        public final boolean isOwner(Instance instance) {
                return this.instance == instance;
        }

        // public void setInstance(Instance instance) {
        //      this.instance = instance;
        // }

        @SuppressWarnings("unchecked")
        public
        List<Node> getNodes() {
                return ListUtils.unmodifiableList(nodes);
        }

        public void assureResolved() {
                if (!isResolved()) {
                        throw new FramsticksException().msg("path is not resolved").arg("path", this);
                }
        }

        public static Path to(@Nonnull Instance instance, String textual) {
                return Path.build().resolve(instance, textual).finish();
        }
}