001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
002 *
003 * Copyright © 2017 MicroBean.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
014 * implied.  See the License for the specific language governing
015 * permissions and limitations under the License.
016 */
017package org.microbean.helm.chart;
018
019import java.io.ByteArrayInputStream;
020import java.io.ByteArrayOutputStream;
021import java.io.IOException;
022import java.io.InputStream;
023
024import java.util.AbstractMap.SimpleImmutableEntry;
025import java.util.Iterator;
026import java.util.Map.Entry;
027import java.util.NoSuchElementException;
028
029import java.util.zip.ZipEntry;
030import java.util.zip.ZipInputStream;
031
032import hapi.chart.ChartOuterClass.Chart; // for javadoc only
033
034/**
035 * A {@link StreamOrientedChartLoader
036 * StreamOrientedChartLoader<ZipInputStream>} that creates
037 * {@link Chart} instances from {@link ZipInputStream} instances.
038 *
039 * @author <a href="https://about.me/lairdnelson"
040 * target="_parent">Laird Nelson</a>
041 *
042 * @see #toNamedInputStreamEntries(ZipInputStream)
043 *
044 * @see StreamOrientedChartLoader
045 */
046public class ZipInputStreamChartLoader extends StreamOrientedChartLoader<ZipInputStream> {
047
048  
049  /*
050   * Constructors.
051   */
052
053  
054  /**
055   * Creates a new {@link ZipInputStreamChartLoader}.
056   */
057  public ZipInputStreamChartLoader() {
058    super();
059  }
060
061
062  /*
063   * Instance methods.
064   */
065
066
067  /**
068   * Converts the supplied {@link ZipInputStream} into an {@link
069   * Iterable} of {@link Entry} instances, each of which consists of
070   * an {@link InputStream} representing an entry within the archive
071   * together with its name.
072   *
073   * <p>This method never returns {@code null}.</p>
074   *
075   * <p>Overrides of this method are not permitted to return {@code
076   * null}.
077   *
078   * @param stream the {@link ZipInputStream} to read; must be
079   * non-{@code null} or an effectively empty {@link Iterable} will be
080   * returned
081   *
082   * @return a non-{@code null} {@link Iterable} of {@link Entry}
083   * instances representing named {@link InputStream}s
084   *
085   * @exception IOException if there is a problem reading from the
086   * supplied {@link ZipInputStream}
087   */
088  @Override
089  protected Iterable<? extends Entry<? extends String, ? extends InputStream>> toNamedInputStreamEntries(final ZipInputStream stream) throws IOException {
090    if (stream == null) {
091      return new EmptyIterable();
092    } else {
093      return new Iterable<Entry<String, InputStream>>() {
094        @Override
095        public Iterator<Entry<String, InputStream>> iterator() {
096          return new Iterator<Entry<String, InputStream>>() {
097            private ZipEntry currentEntry;
098            
099            {
100              try {
101                this.currentEntry = stream.getNextEntry();
102              } catch (final IOException ignore) {
103                this.currentEntry = null;
104              }
105            }
106            
107            @Override
108            public boolean hasNext() {
109              return this.currentEntry != null;
110            }
111            
112            @Override
113            public Entry<String, InputStream> next() {
114              if (this.currentEntry == null) {
115                throw new NoSuchElementException();
116              }
117              ByteArrayInputStream bais = null;
118              try (final ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
119                int bytesRead = 0;
120                final byte bytes[] = new byte[4096];
121                while((bytesRead = stream.read(bytes)) >= 0) {
122                  baos.write(bytes, 0, bytesRead);
123                }
124                baos.flush();
125                bais = new ByteArrayInputStream(baos.toByteArray());
126              } catch (final IOException wrapMe) {
127                throw (NoSuchElementException)new NoSuchElementException(wrapMe.getMessage()).initCause(wrapMe);
128              }
129              final Entry<String, InputStream> returnValue = new SimpleImmutableEntry<>(this.currentEntry.getName(), bais);
130              try {
131                this.currentEntry = stream.getNextEntry();
132              } catch (final IOException ignore) {
133                this.currentEntry = null;
134              }
135              return returnValue;
136            }
137          };
138        }
139      };
140    }
141  }
142
143  /**
144   * Does nothing on purpose.
145   *
146   * @exception IOException if a subclass has overridden this method
147   * and an error occurs
148   */
149  @Override
150  public void close() throws IOException {
151
152  }
153
154  
155}