eu.larkc.iris.storage.FactsTap.java Source code

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Here is the source code for eu.larkc.iris.storage.FactsTap.java

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/*
 * Copyright 2010 Softgress - http://www.softgress.com/
 * 
 * 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 eu.larkc.iris.storage;

import java.io.IOException;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.deri.iris.api.basics.IAtom;
import org.deri.iris.api.basics.IPredicate;

import cascading.tap.Tap;
import cascading.tap.hadoop.TapCollector;
import cascading.tap.hadoop.TapIterator;
import cascading.tuple.Fields;
import cascading.tuple.TupleEntryCollector;
import cascading.tuple.TupleEntryIterator;

/**
 * Cascading tap for accesing/writing iris style atoms from different datasources
 * 
 * @history
 * @author valer
 *
 */
public class FactsTap extends Tap {

    /**
     * serialVersionUID
     */
    private static final long serialVersionUID = -5174403815272616996L;

    private String factsConfigurationClass = null;
    private IPredicate[] predicates = null;
    private IAtom atom = null;
    private String storageId;

    private FactsTap(FactsScheme scheme) {
        super(scheme);
    }

    FactsTap(String factsConfigurationClass, Fields fields, String storageId, IPredicate... predicates) {
        this(new FactsScheme(fields, storageId, predicates));
        this.factsConfigurationClass = factsConfigurationClass;
        this.predicates = predicates;
        this.storageId = storageId;
    }

    FactsTap(String factsConfigurationClass, Fields fields, String storageId, IAtom atom) {
        this(new FactsScheme(fields, storageId, atom));
        this.factsConfigurationClass = factsConfigurationClass;
        this.atom = atom;
        this.storageId = storageId;
    }

    FactsTap(String factsConfigurationClass, Fields fields, String storageId) {
        this(new FactsScheme(fields, storageId));
        this.factsConfigurationClass = factsConfigurationClass;
        this.storageId = storageId;
    }

    @Override
    public Path getPath() {
        if (atom != null) {
            return new Path(storageId + "/" + atom.getPredicate().getPredicateSymbol());
        } else if (predicates != null && predicates.length > 0) {
            StringBuilder sb = new StringBuilder();
            for (IPredicate predicate : predicates) {
                if (sb.length() > 0) {
                    sb.append(";");
                }
                sb.append(storageId + "/" + predicate.getPredicateSymbol());
            }
            return new Path(sb.toString());
        } else {
            return new Path(storageId);
        }
    }

    @Override
    public TupleEntryIterator openForRead(JobConf conf) throws IOException {
        return new TupleEntryIterator(getSourceFields(), new TapIterator(this, conf));
    }

    @Override
    public TupleEntryCollector openForWrite(JobConf conf) throws IOException {
        return new TapCollector(this, conf);
    }

    @Override
    public boolean makeDirs(JobConf conf) throws IOException {
        return false;
    }

    @Override
    public boolean deletePath(JobConf conf) throws IOException {
        return false;
    }

    @Override
    public boolean pathExists(JobConf conf) throws IOException {
        return true;
    }

    @Override
    public long getPathModified(JobConf conf) throws IOException {
        return 0;
    }

    @Override
    public boolean isSink() {
        return atom == null && predicates == null;
    }

    @Override
    public boolean isSource() {
        return true;
    }

    @Override
    public void sourceInit(JobConf jobConf) throws IOException {
        // a hack for MultiInputFormat to see that there is a child format
        FileInputFormat.setInputPaths(jobConf, getPath());

        jobConf.set(IFactsConfiguration.FACTS_CONFIGURATION_CLASS, factsConfigurationClass);
        if (isSource()) {
            StringBuilder sb = new StringBuilder();
            if (atom != null) {
                sb.append(atom.getPredicate().getPredicateSymbol());
            }
            if (predicates != null && predicates.length > 0) {
                for (IPredicate predicate : predicates) {
                    if (sb.length() > 0) {
                        sb.append(",");
                    }
                    sb.append(predicate.getPredicateSymbol());
                }
            }
            jobConf.set(IFactsConfiguration.PREDICATE_FILTER, sb.toString());
        }

        IFactsConfiguration factsConfiguration = FactsConfigurationFactory.getFactsConfiguration(jobConf);
        factsConfiguration.setSourceStorageId(storageId);

        //RdfFactsConfiguration.configure(conf, rdf2GoImpl, serverURL, repositoryID);

        super.sourceInit(jobConf);
    }

    @Override
    public void sinkInit(JobConf jobConf) throws IOException {
        if (!isSink())
            return;

        jobConf.set(IFactsConfiguration.FACTS_CONFIGURATION_CLASS, factsConfigurationClass);

        IFactsConfiguration factsConfiguration = FactsConfigurationFactory.getFactsConfiguration(jobConf);
        factsConfiguration.setSinkStorageId(storageId);

        //RdfFactsConfiguration.configure(conf, rdf2GoImpl, serverURL, repositoryID);

        super.sinkInit(jobConf);
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("facts[");
        sb.append((storageId == null ? "" : ("store:" + storageId)));
        if (atom != null) {
            sb.append(", " + "predicate:" + atom.getPredicate().getPredicateSymbol());
        }
        if (predicates != null && predicates.length > 0) {
            //sb.append(", " + "predicate:" + predicates[0].getPredicateSymbol());
            for (IPredicate predicate : predicates) {
                sb.append(", " + "predicate:" + predicate.getPredicateSymbol());
            }
        }
        sb.append("]");
        return sb.toString();
    }

    public boolean hasNewInferences() {
        if (!isSink()) {
            return false;
        }
        return false;
    }

}