Merge pull request #8 from alexfu/feature/composition-builder

Improve statement string builder

src/main/java/com/alexfu/sqlitequerybuilder/SQLiteQueryBuilder.java

@@ -1,13 +1,15 @@
 package com.alexfu.sqlitequerybuilder;
 
-import com.alexfu.sqlitequerybuilder.impl.SelectImpl;
+import com.alexfu.sqlitequerybuilder.builder.SelectBuilder;
+import com.alexfu.sqlitequerybuilder.builder.SelectFieldBuilder;
+import com.alexfu.sqlitequerybuilder.builder.SelectTypeBuilder;
 
 public class SQLiteQueryBuilder {
-  public static Select select(String... fields) {
-    return new SelectImpl(fields);
+  public static SelectBuilder select(String... fields) {
+    return new SelectFieldBuilder(fields);
   }
 
-  public static Select select() {
-    return new SelectImpl();
+  public static SelectBuilder select(SelectType type) {
+    return new SelectTypeBuilder(type);
   }
 }

src/main/java/com/alexfu/sqlitequerybuilder/SegmentBuilder.java

@@ -0,0 +1,5 @@
+package com.alexfu.sqlitequerybuilder;
+
+public interface SegmentBuilder {
+  public String build();
+}

src/main/java/com/alexfu/sqlitequerybuilder/SelectType.java

@@ -1,5 +1,31 @@
 package com.alexfu.sqlitequerybuilder;
 
-public interface SelectType {
-  public SelectFrom from(String table);
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectType implements SegmentBuilder {
+
+  private enum Type {
+    DISTINCT, ALL
+  }
+
+  private Type type;
+  private String[] fields;
+
+  private SelectType(Type type, String...fields) {
+    this.type = type;
+    this.fields = fields;
+  }
+
+  public static SelectType DISTINCT(String... fields) {
+    return new SelectType(Type.DISTINCT, fields);
+  }
+
+  public static SelectType ALL(String... fields) {
+    return new SelectType(Type.ALL, fields);
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", type.toString(), StringUtils.join(",", fields));
+  }
 }

src/main/java/com/alexfu/sqlitequerybuilder/builder/JoinOnBuilder.java

@@ -0,0 +1,28 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class JoinOnBuilder implements SegmentBuilder {
+
+  private SelectJoinBuilder prefix;
+  private String condition;
+
+  public JoinOnBuilder(SelectJoinBuilder prefix, String condition) {
+    this.prefix = prefix;
+    this.condition = condition;
+  }
+
+  public SelectWhereBuilder where(String condition) {
+    return new SelectWhereBuilder(this, condition);
+  }
+
+  public SelectJoinBuilder join(String table) {
+    return new SelectJoinBuilder(this, table);
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", prefix.build(), "ON", condition);
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectAndBuilder.java

@@ -0,0 +1,20 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectAndBuilder implements SegmentBuilder {
+
+  private SelectWhereBuilder prefix;
+  private String condition;
+
+  public SelectAndBuilder(SelectWhereBuilder prefix, String condition) {
+    this.prefix = prefix;
+    this.condition = condition;
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", prefix.build(), "AND", condition);
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectBuilder.java

@@ -0,0 +1,9 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+
+public abstract class SelectBuilder implements SegmentBuilder {
+  public SelectFromBuilder from(String table) {
+    return new SelectFromBuilder(this, table);
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectFieldBuilder.java

@@ -0,0 +1,17 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectFieldBuilder extends SelectBuilder {
+
+  private String[] fields;
+
+  public SelectFieldBuilder(String...fields) {
+    this.fields = fields;
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", "SELECT", StringUtils.join(",", fields));
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectFromBuilder.java

@@ -0,0 +1,36 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectFromBuilder implements SegmentBuilder {
+
+  private SelectBuilder prefix;
+  private String[] tables;
+
+  public SelectFromBuilder(SelectBuilder prefix, String...tables) {
+    this.prefix = prefix;
+    this.tables = tables;
+  }
+
+  public SelectWhereBuilder where(String condition) {
+    return new SelectWhereBuilder(this, condition);
+  }
+
+  public SelectJoinBuilder join(String table) {
+    return new SelectJoinBuilder(this, table);
+  }
+
+  public SelectOrderByBuilder orderBy(String column) {
+    return new SelectOrderByBuilder(this, column);
+  }
+
+  public SelectGroupByBuilder groupBy(String column) {
+    return new SelectGroupByBuilder(this, column);
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", prefix.build(), "FROM", StringUtils.join(",", tables));
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectGroupByBuilder.java

@@ -0,0 +1,20 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectGroupByBuilder implements SegmentBuilder {
+
+  private SelectFromBuilder prefix;
+  private String column;
+
+  public SelectGroupByBuilder(SelectFromBuilder prefix, String column) {
+    this.prefix = prefix;
+    this.column = column;
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", prefix.build(), "GROUP BY", column);
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectJoinBuilder.java

@@ -0,0 +1,25 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+
+import static com.alexfu.sqlitequerybuilder.utils.StringUtils.join;
+
+public class SelectJoinBuilder implements SegmentBuilder {
+
+  private SegmentBuilder prefix;
+  private String table;
+
+  public SelectJoinBuilder(SegmentBuilder prefix, String table) {
+    this.prefix = prefix;
+    this.table = table;
+  }
+
+  public JoinOnBuilder on(String condition) {
+    return new JoinOnBuilder(this, condition);
+  }
+
+  @Override
+  public String build() {
+    return join(" ", prefix.build(), "JOIN", table);
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectLimitBuilder.java

@@ -0,0 +1,35 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectLimitBuilder implements SegmentBuilder {
+
+  private SegmentBuilder prefix;
+  private int limit = -1;
+  private int offset = -1;
+
+  public SelectLimitBuilder(SegmentBuilder prefix, int limit) {
+    this.prefix = prefix;
+    this.limit = limit;
+  }
+
+  public SelectLimitBuilder offset(int offset) {
+    this.offset = offset;
+    return this;
+  }
+
+  @Override
+  public String build() {
+    String offsetString = null;
+    if (offset != -1) {
+      offsetString = StringUtils.join(" ", "OFFSET", String.valueOf(offset));
+    }
+
+    String result = StringUtils.join(" ", prefix.build(), "LIMIT", String.valueOf(limit));
+    if (offsetString != null) {
+      result = StringUtils.join(" ", result, offsetString);
+    }
+    return result;
+  }
+}

src/main/java/com/alexfu/sqlitequerybuilder/builder/SelectOrderByBuilder.java

@@ -0,0 +1,28 @@
+package com.alexfu.sqlitequerybuilder.builder;
+
+import com.alexfu.sqlitequerybuilder.SegmentBuilder;
+import com.alexfu.sqlitequerybuilder.utils.StringUtils;
+
+public class SelectOrderByBuilder implements SegmentBuilder {
+
+  private SegmentBuilder prefix;
+  private String column;
+
+  public SelectOrderByBuilder(SegmentBuilder prefix, String column) {
+    this.prefix = prefix;
+    this.column = column;
+  }
+
+  public SelectOrderTermBuilder asc() {
+    return new SelectOrderTermBuilder(this, SelectOrderTermBuilder.Term.ASC);
+  }
+
+  public SelectOrderTermBuilder desc() {
+    return new SelectOrderTermBuilder(this, SelectOrderTermBuilder.Term.DESC);
+  }
+
+  @Override
+  public String build() {
+    return StringUtils.join(" ", prefix.build(), "ORDER BY", column);
+  }
+}