Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 gobblin.configuration; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.util.List; import java.util.Map; import java.util.Properties; import java.util.Set; import com.google.common.base.Joiner; import com.google.common.base.Preconditions; import com.google.common.base.Splitter; import com.google.common.collect.ImmutableSet; import com.google.common.collect.ImmutableSortedSet; import com.google.common.collect.Iterables; import com.google.common.collect.Maps; import com.google.common.collect.Sets; import com.google.gson.JsonArray; import com.google.gson.JsonElement; import com.google.gson.JsonParser; import lombok.EqualsAndHashCode; import lombok.Getter; import gobblin.compat.hadoop.TextSerializer; import gobblin.compat.hadoop.WritableShim; /** * A serializable wrapper class that can be persisted for {@link Properties}. * * @author kgoodhop */ @EqualsAndHashCode(exclude = { "jsonParser" }) public class State implements WritableShim { private static final Joiner LIST_JOINER = Joiner.on(","); private static final Splitter LIST_SPLITTER = Splitter.on(",").trimResults().omitEmptyStrings(); private String id; // State contains two parts: commonProperties and specProperties (specProperties overrides commonProperties). @Getter private Properties commonProperties; @Getter private Properties specProperties; private final JsonParser jsonParser = new JsonParser(); public State() { this.specProperties = new Properties(); this.commonProperties = new Properties(); } public State(Properties properties) { this.specProperties = properties; this.commonProperties = new Properties(); } public State(State otherState) { this.commonProperties = otherState.getCommonProperties(); this.specProperties = new Properties(); this.specProperties.putAll(otherState.getProperties()); for (Object key : this.commonProperties.keySet()) { if (this.specProperties.containsKey(key) && this.commonProperties.get(key).equals(this.specProperties.get(key))) { this.specProperties.remove(key); } } } /** * Return a copy of the underlying {@link Properties} object. * * @return A copy of the underlying {@link Properties} object. */ public Properties getProperties() { // a.putAll(b) iterates over the entries of b. Synchronizing on b prevents concurrent modification on b. synchronized (this.specProperties) { Properties props = new Properties(); if (this.commonProperties != null) { props.putAll(this.commonProperties); } props.putAll(this.specProperties); return props; } } /** * Populates this instance with properties of the other instance. * * @param otherState the other {@link State} instance */ public void addAll(State otherState) { Properties diffCommonProps = new Properties(); diffCommonProps .putAll(Maps.difference(this.commonProperties, otherState.commonProperties).entriesOnlyOnRight()); addAll(diffCommonProps); addAll(otherState.specProperties); } /** * Populates this instance with values of a {@link Properties} instance. * * @param properties a {@link Properties} instance */ public void addAll(Properties properties) { this.specProperties.putAll(properties); } /** * Add properties in a {@link State} instance that are not in the current instance. * * @param otherState a {@link State} instance */ public void addAllIfNotExist(State otherState) { addAllIfNotExist(otherState.commonProperties); addAllIfNotExist(otherState.specProperties); } /** * Add properties in a {@link Properties} instance that are not in the current instance. * * @param properties a {@link Properties} instance */ public void addAllIfNotExist(Properties properties) { for (String key : properties.stringPropertyNames()) { if (!this.specProperties.containsKey(key) && !this.commonProperties.containsKey(key)) { this.specProperties.setProperty(key, properties.getProperty(key)); } } } /** * Add properties in a {@link State} instance that are in the current instance. * * @param otherState a {@link State} instance */ public void overrideWith(State otherState) { overrideWith(otherState.commonProperties); overrideWith(otherState.specProperties); } /** * Add properties in a {@link Properties} instance that are in the current instance. * * @param properties a {@link Properties} instance */ public void overrideWith(Properties properties) { for (String key : properties.stringPropertyNames()) { if (this.specProperties.containsKey(key) || this.commonProperties.containsKey(key)) { this.specProperties.setProperty(key, properties.getProperty(key)); } } } /** * Set the id used for state persistence and logging. * * @param id id of this instance */ public void setId(String id) { this.id = id; } /** * Get the id of this instance. * * @return id of this instance */ public String getId() { return this.id; } /** * Set a property. * * <p> * Both key and value are stored as strings. * </p> * * @param key property key * @param value property value */ public void setProp(String key, Object value) { this.specProperties.put(key, value.toString()); } /** * Override existing {@link #commonProperties} and {@link #specProperties}. * @param commonProperties * @param specProperties */ public void setProps(Properties commonProperties, Properties specProperties) { this.commonProperties = commonProperties; this.specProperties = specProperties; } /** * Appends the input value to a list property that can be retrieved with {@link #getPropAsList}. * * <p> * List properties are internally stored as comma separated strings. Adding a value that contains commas (for * example "a,b,c") will essentially add multiple values to the property ("a", "b", and "c"). This is * similar to the way that {@link org.apache.hadoop.conf.Configuration} works. * </p> * * @param key property key * @param value property value (if it includes commas, it will be split by the commas). */ public synchronized void appendToListProp(String key, String value) { if (contains(key)) { setProp(key, LIST_JOINER.join(getProp(key), value)); } else { setProp(key, value); } } /** * Appends the input value to a set property that can be retrieved with {@link #getPropAsSet}. * * <p> * Set properties are internally stored as comma separated strings. Adding a value that contains commas (for * example "a,b,c") will essentially add multiple values to the property ("a", "b", and "c"). This is * similar to the way that {@link org.apache.hadoop.conf.Configuration} works. * </p> * * @param key property key * @param value property value (if it includes commas, it will be split by the commas). */ public synchronized void appendToSetProp(String key, String value) { Set<String> set = value == null ? Sets.<String>newHashSet() : Sets.newHashSet(LIST_SPLITTER.splitToList(value)); if (contains(key)) { set.addAll(getPropAsSet(key)); } setProp(key, LIST_JOINER.join(set)); } /** * Get the value of a property. * * @param key property key * @return value associated with the key as a string or <code>null</code> if the property is not set */ public String getProp(String key) { if (this.specProperties.containsKey(key)) { return this.specProperties.getProperty(key); } return this.commonProperties.getProperty(key); } /** * Get the value of a property, using the given default value if the property is not set. * * @param key property key * @param def default value * @return value associated with the key or the default value if the property is not set */ public String getProp(String key, String def) { if (this.specProperties.containsKey(key)) { return this.specProperties.getProperty(key); } return this.commonProperties.getProperty(key, def); } /** * Get the value of a comma separated property as a {@link List} of strings. * * @param key property key * @return value associated with the key as a {@link List} of strings */ public List<String> getPropAsList(String key) { return LIST_SPLITTER.splitToList(getProp(key)); } /** * Get the value of a property as a list of strings, using the given default value if the property is not set. * * @param key property key * @param def default value * @return value (the default value if the property is not set) associated with the key as a list of strings */ public List<String> getPropAsList(String key, String def) { return LIST_SPLITTER.splitToList(getProp(key, def)); } /** * Get the value of a comma separated property as a {@link Set} of strings. * * @param key property key * @return value associated with the key as a {@link Set} of strings */ public Set<String> getPropAsSet(String key) { return ImmutableSet.copyOf(LIST_SPLITTER.splitToList(getProp(key))); } /** * Get the value of a comma separated property as a {@link Set} of strings. * * @param key property key * @param def default value * @return value (the default value if the property is not set) associated with the key as a {@link Set} of strings */ public Set<String> getPropAsSet(String key, String def) { return ImmutableSet.copyOf(LIST_SPLITTER.splitToList(getProp(key, def))); } /** * Get the value of a property as a case insensitive {@link Set} of strings. * * @param key property key * @return value associated with the key as a case insensitive {@link Set} of strings */ public Set<String> getPropAsCaseInsensitiveSet(String key) { return ImmutableSortedSet.copyOf(String.CASE_INSENSITIVE_ORDER, LIST_SPLITTER.split(getProp(key))); } /** * Get the value of a property as a case insensitive {@link Set} of strings, using the given default value if the property is not set. * * @param key property key * @param def default value * @return value associated with the key as a case insensitive {@link Set} of strings */ public Set<String> getPropAsCaseInsensitiveSet(String key, String def) { return ImmutableSortedSet.copyOf(String.CASE_INSENSITIVE_ORDER, LIST_SPLITTER.split(getProp(key, def))); } /** * Get the value of a property as a long integer. * * @param key property key * @return long integer value associated with the key */ public long getPropAsLong(String key) { return Long.parseLong(getProp(key)); } /** * Get the value of a property as a long integer, using the given default value if the property is not set. * * @param key property key * @param def default value * @return long integer value associated with the key or the default value if the property is not set */ public long getPropAsLong(String key, long def) { return Long.parseLong(getProp(key, String.valueOf(def))); } /** * Get the value of a property as an integer. * * @param key property key * @return integer value associated with the key */ public int getPropAsInt(String key) { return Integer.parseInt(getProp(key)); } /** * Get the value of a property as an integer, using the given default value if the property is not set. * * @param key property key * @param def default value * @return integer value associated with the key or the default value if the property is not set */ public int getPropAsInt(String key, int def) { return Integer.parseInt(getProp(key, String.valueOf(def))); } /** * Get the value of a property as a short. * * @param key property key * @return short value associated with the key */ public short getPropAsShort(String key) { return Short.parseShort(getProp(key)); } /** * Get the value of a property as a short. * * @param key property key * @param radix radix used to parse the value * @return short value associated with the key */ public short getPropAsShortWithRadix(String key, int radix) { return Short.parseShort(getProp(key), radix); } /** * Get the value of a property as an short, using the given default value if the property is not set. * * @param key property key * @param def default value * @return short value associated with the key or the default value if the property is not set */ public short getPropAsShort(String key, short def) { return Short.parseShort(getProp(key, String.valueOf(def))); } /** * Get the value of a property as an short, using the given default value if the property is not set. * * @param key property key * @param def default value * @param radix radix used to parse the value * @return short value associated with the key or the default value if the property is not set */ public short getPropAsShortWithRadix(String key, short def, int radix) { return contains(key) ? Short.parseShort(getProp(key), radix) : def; } /** * Get the value of a property as a double. * * @param key property key * @return double value associated with the key */ public double getPropAsDouble(String key) { return Double.parseDouble(getProp(key)); } /** * Get the value of a property as a double, using the given default value if the property is not set. * * @param key property key * @param def default value * @return double value associated with the key or the default value if the property is not set */ public double getPropAsDouble(String key, double def) { return Double.parseDouble(getProp(key, String.valueOf(def))); } /** * Get the value of a property as a boolean. * * @param key property key * @return boolean value associated with the key */ public boolean getPropAsBoolean(String key) { return Boolean.parseBoolean(getProp(key)); } /** * Get the value of a property as a boolean, using the given default value if the property is not set. * * @param key property key * @param def default value * @return boolean value associated with the key or the default value if the property is not set */ public boolean getPropAsBoolean(String key, boolean def) { return Boolean.parseBoolean(getProp(key, String.valueOf(def))); } /** * Get the value of a property as a {@link JsonArray}. * * @param key property key * @return {@link JsonArray} value associated with the key */ public JsonArray getPropAsJsonArray(String key) { JsonElement jsonElement = this.jsonParser.parse(getProp(key)); Preconditions.checkArgument(jsonElement.isJsonArray(), "Value for key " + key + " is malformed, it must be a JsonArray: " + jsonElement); return jsonElement.getAsJsonArray(); } /** * Remove a property if it exists. * * @param key property key */ public void removeProp(String key) { this.specProperties.remove(key); if (this.commonProperties.containsKey(key)) { // This case should not happen. Properties commonPropsCopy = new Properties(); commonPropsCopy.putAll(this.commonProperties); commonPropsCopy.remove(key); this.commonProperties = commonPropsCopy; } } /** * @deprecated Use {@link #getProp(String)} */ @Deprecated protected String getProperty(String key) { return getProp(key); } /** * @deprecated Use {@link #getProp(String, String)} */ @Deprecated protected String getProperty(String key, String def) { return getProp(key, def); } /** * Get the names of all the properties set in a {@link Set}. * * @return names of all the properties set in a {@link Set} */ public Set<String> getPropertyNames() { return Sets.newHashSet(Iterables.concat(this.commonProperties.stringPropertyNames(), this.specProperties.stringPropertyNames())); } /** * Check if a property is set. * * @param key property key * @return <code>true</code> if the property is set or <code>false</code> otherwise */ public boolean contains(String key) { return this.specProperties.containsKey(key) || this.commonProperties.containsKey(key); } @Override public void readFields(DataInput in) throws IOException { int numEntries = in.readInt(); while (numEntries-- > 0) { String key = TextSerializer.readTextAsString(in).intern(); String value = TextSerializer.readTextAsString(in).intern(); this.specProperties.put(key, value); } } @Override public void write(DataOutput out) throws IOException { out.writeInt(this.commonProperties.size() + this.specProperties.size()); for (Object key : this.commonProperties.keySet()) { TextSerializer.writeStringAsText(out, (String) key); TextSerializer.writeStringAsText(out, this.commonProperties.getProperty((String) key)); } for (Object key : this.specProperties.keySet()) { TextSerializer.writeStringAsText(out, (String) key); TextSerializer.writeStringAsText(out, this.specProperties.getProperty((String) key)); } } @Override public String toString() { return "Common:" + this.commonProperties.toString() + "\n Specific: " + this.specProperties.toString(); } }