com.ibm.jaql.lang.expr.system.LsFn.java Source code

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Here is the source code for com.ibm.jaql.lang.expr.system.LsFn.java

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/*
 * Copyright (C) IBM Corp. 2010.
 * 
 * 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 com.ibm.jaql.lang.expr.system;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import com.ibm.jaql.json.type.BufferedJsonRecord;
import com.ibm.jaql.json.type.JsonEnum;
import com.ibm.jaql.json.type.JsonString;
import com.ibm.jaql.json.type.JsonUtil;
import com.ibm.jaql.json.type.JsonValue;
import com.ibm.jaql.json.type.MutableJsonDate;
import com.ibm.jaql.json.type.MutableJsonLong;
import com.ibm.jaql.json.type.MutableJsonString;
import com.ibm.jaql.json.util.JsonIterator;
import com.ibm.jaql.lang.core.Context;
import com.ibm.jaql.lang.expr.core.Expr;
import com.ibm.jaql.lang.expr.core.IterExpr;
import com.ibm.jaql.lang.expr.function.DefaultBuiltInFunctionDescriptor;
import com.ibm.jaql.util.Bool3;
import com.ibm.jaql.util.hadoop.HadoopShim;

/**
 * ls(glob) 
 * 
 */
public class LsFn extends IterExpr {
    public static class Descriptor extends DefaultBuiltInFunctionDescriptor.Par11 {
        public Descriptor() {
            super("ls", LsFn.class); // TODO: add options, like recursive, etc to define filter
        }
    }

    public static enum LsField implements JsonEnum {
        ACCESS_TIME("accessTime"), MODIFY_TIME("modifyTime"), LENGTH("length"), BLOCK_SIZE(
                "blockSize"), REPLICATION(
                        "replication"), PATH("path"), OWNER("owner"), GROUP("group"), PERMISSION("permission");

        public static final JsonString[] names = JsonUtil.jsonStrings(LsField.values());

        protected final JsonString name;

        private LsField(String name) {
            this.name = new JsonString(name);
        }

        @Override
        public JsonString jsonString() {
            return name;
        }
    }

    public LsFn(Expr... exprs) {
        super(exprs);
    }

    @Override
    public Bool3 evaluatesChildOnce(int i) {
        return Bool3.TRUE;
    }

    @Override
    public boolean isMappable(int i) {
        return i == 0;
    }

    @Override
    public JsonIterator iter(final Context context) throws Exception {
        JsonString glob = (JsonString) exprs[0].eval(context);
        // Configuration conf = context.getConfiguration();
        Configuration conf = new Configuration(); // TODO: get from context, incl options
        //URI uri;
        //FileSystem fs = FileSystem.get(uri, conf);
        Path inpath = new Path(glob.toString());
        FileSystem fs = inpath.getFileSystem(conf);
        //final FileStatus[] stats = fs.listStatus(path, filter);
        final FileStatus[] stats = fs.globStatus(inpath);

        if (stats == null || stats.length == 0) {
            return JsonIterator.EMPTY;
        }

        final MutableJsonDate accessTime = new MutableJsonDate();
        final MutableJsonDate modifyTime = new MutableJsonDate();
        final MutableJsonLong length = new MutableJsonLong();
        final MutableJsonLong blockSize = new MutableJsonLong();
        final MutableJsonLong replication = new MutableJsonLong();
        final MutableJsonString path = new MutableJsonString();
        final MutableJsonString owner = new MutableJsonString();
        final MutableJsonString group = new MutableJsonString();
        final MutableJsonString permission = new MutableJsonString();
        final JsonValue[] values = new JsonValue[] { accessTime, modifyTime, length, blockSize, replication, path,
                owner, group, permission };
        final BufferedJsonRecord rec = new BufferedJsonRecord();
        rec.set(LsField.names, values, values.length, false);

        return new JsonIterator(rec) {
            int i = 0;

            @Override
            public boolean moveNext() throws Exception {
                if (i >= stats.length) {
                    return false;
                }

                FileStatus stat = stats[i++];
                // fs.getUri().toString();
                long x = HadoopShim.getAccessTime(stat);
                if (x <= 0) {
                    values[LsField.ACCESS_TIME.ordinal()] = null;
                } else {
                    accessTime.set(x);
                    values[LsField.ACCESS_TIME.ordinal()] = accessTime;
                }
                modifyTime.set(stat.getModificationTime());
                length.set(stat.getLen());
                blockSize.set(stat.getBlockSize());
                replication.set(stat.getReplication());
                path.setCopy(stat.getPath().toString());
                owner.setCopy(stat.getOwner());
                group.setCopy(stat.getGroup());
                permission.setCopy(stat.getPermission().toString());
                return true;
            }
        };
    }

}