org.commonjava.cartographer.graph.spi.jung.model.JungGraphPath.java Source code

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Here is the source code for org.commonjava.cartographer.graph.spi.jung.model.JungGraphPath.java

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/**
 * Copyright (C) 2012 Red Hat, Inc. (jdcasey@commonjava.org)
 *
 * 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.commonjava.cartographer.graph.spi.jung.model;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang.StringUtils;
import org.commonjava.cartographer.graph.model.GraphPath;
import org.commonjava.maven.atlas.graph.rel.ProjectRelationship;
import org.commonjava.maven.atlas.ident.ref.ProjectVersionRef;

public class JungGraphPath implements GraphPath<ProjectRelationship<?, ?>> {

    private final ProjectRelationship<?, ?>[] rels;

    private final ProjectVersionRef root;

    public JungGraphPath(final ProjectVersionRef root) {
        this.root = root;
        this.rels = new ProjectRelationship<?, ?>[] {};
    }

    public JungGraphPath(final ProjectRelationship<?, ?>... rels) {
        this.root = null;
        this.rels = rels;
    }

    public JungGraphPath(final JungGraphPath parent, final ProjectRelationship<?, ?> child) {
        this.root = null;
        if (parent == null) {
            rels = new ProjectRelationship<?, ?>[] { child };
        } else {
            final int parentLen = parent.rels.length;
            this.rels = new ProjectRelationship<?, ?>[parentLen + 1];
            System.arraycopy(parent.rels, 0, this.rels, 0, parentLen);
            this.rels[parentLen] = child;
        }
    }

    public JungGraphPath(final List<ProjectRelationship<?, ?>> path) {
        this.root = null;
        this.rels = path.toArray(new ProjectRelationship<?, ?>[path.size()]);
    }

    public ProjectVersionRef getTargetGAV() {
        if (root != null) {
            return root;
        } else if (rels.length > 0) {
            return rels[rels.length - 1].getTarget().asProjectVersionRef();
        }

        return null;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + Arrays.hashCode(rels);
        return result;
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final JungGraphPath other = (JungGraphPath) obj;
        return Arrays.equals(rels, other.rels);
    }

    @Override
    public Iterator<ProjectRelationship<?, ?>> iterator() {
        return new Iterator<ProjectRelationship<?, ?>>() {
            private int next = 0;

            @Override
            public boolean hasNext() {
                return rels.length > next;
            }

            @Override
            public ProjectRelationship<?, ?> next() {
                return rels[next++];
            }

            @Override
            public void remove() {
                throw new UnsupportedOperationException("Immutable array of GAV's. Remove not supported.");
            }
        };
    }

    public List<ProjectRelationship<?, ?>> getPathElements() {
        return rels.length == 0 ? Collections.<ProjectRelationship<?, ?>>emptyList() : Arrays.asList(rels);
    }

    public boolean hasCycle() {
        if (rels.length < 1) {
            return false;
        }

        final Set<ProjectVersionRef> declared = new HashSet<ProjectVersionRef>(rels.length);
        for (final ProjectRelationship<?, ?> item : rels) {
            // NOTE: order is important here, in case it's a terminal parent relationship.
            if (declared.contains(item.getTarget().asProjectVersionRef()) || !declared.add(item.getDeclaring())) {
                return true;
            }
        }

        return false;
    }

    @Override
    public String getKey() {
        return DigestUtils.shaHex(StringUtils.join(rels, ","));
    }

}